Articles

Case Presentation

A 65-year-old man with severe chronic obstructive disease (COPD; forced expiratory volume in 1 second/forced vital capacity ratio [FEV₁/FVC], 27; FEV₁ 25% of predicted; residual volume 170% of predicted for his age and height) was seen in the pulmonary clinic. His medications include a long-acting beta agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination that he uses twice daily as advised. He uses his rescue albuterol inhaler roughly once a week. The patient complains of severe disabling shortness of breath with exertion and severe limitation of his quality of life because of his inability to lead a normal active life. He is on 2 L/min of oxygen at all times. He has received pulmonary rehabilitation in hopes of improving his quality of life but can only climb a flight of stairs before he must stop to rest. He asks about options but does not want to consider lung transplantation today. His most recent chest computed tomography (CT) scan demonstrates upper lobe predominant emphysematous changes with no masses or nodules.

What are the patient's options at this time?

Lung volume reduction surgery (LVRS) attempts to reduce space-occupying severely diseased, hyperexpanded lung, thus allowing the relatively normal adjoining lung parenchyma to expand into the vacated space and function effectively.¹ Hence, such therapies are suitable for patients with emphysematous lungs and not those with bronchitic-predominant COPD. LVRS offers a greater chance of improvement in exercise capacity, lung function, quality of life, and dyspnea in the correctly chosen patient population, as compared with pharmacologic management alone.² However, the procedure is associated with risks, including higher short-term morbidity and mortality.² Patients with predominantly upper-lobe emphysema and a low maximal workload after rehabilitation were noted to have lower mortality, a greater probability of improvement in exercise capacity, and a greater probability of improvement in symptoms if they underwent surgery compared to medical therapy alone.² On the contrary, patients with predominantly non–upper-lobe emphysema and a high maximal workload after rehabilitation had higher mortality if they underwent surgery compared to receiving medical therapy alone.² Thus, a subgroup of patients with homogeneous emphysema symmetrically affecting the upper and lower lobes are considered to be unlikely to benefit from this surgery.^2,3

Valves and other methods of lung volume reduction such as coils, sealants, intrapulmonary vents, and thermal vapor in the bronchi or subsegmental airways have emerged as new techniques for nonsurgical lung volume reduction.^4-9 Endobronchial-valve therapy is associated with improvement in lung function and with clinical benefits that are greatest in the presence of heterogeneous lung involvement. This works by the same principle as LVRS, by reduction of the most severely diseased lung units, expansion of the more viable, less emphysematous lung results in substantial improvements in lung mechanics.^10,11 The most important complications of this procedure include pneumonia, pneumothorax, hemoptysis, and increased frequency of COPD exacerbation in the following 30 days. The fact that a high-heterogeneity subgroup had greater improvements in both the FEV₁ and distance on the 6-minute walk test than did patients with lower heterogeneity supports the use of quantitative high-resolution computed tomography (HRCT) in selecting patients for endobronchial-valve therapy.¹² The HRCT scans also help in identifying those with complete fissures, a marker of lack of collateral ventilation (CV+) between different lobes. Presence of CV+ state predicts failure of endobronchial valve and all forms of endoscopic LVRS.¹³ Bronchoscopic thermal vapor ablation (BTVA) therapy can potentially work on a subsegmental level and be successful for treatment of emphysema with lack of intact fissures on CT scans. Other methods that have the potential to be effective in those with collateral ventilation would be endoscopic coil therapy and polymeric lung volume reduction.^11,14 Unfortunately, there are no randomized controlled trial data demonstrating clinically meaningful improvement following coil therapy or polymeric lung volume reduction in this CV+ patient population. Vapor therapy is perhaps the only technique that has been found to be effective in upper lobe predominant emphysema even with CV+ status.¹³

Our patient has evidence of air trapping and emphysema based on a high residual volume. A CT scan of the chest can determine the nature of the emphysema (heterogeneous versus homogenous) and based on these findings, further determination of the best strategy for lung volume reduction can be made.

Is there a role for long-term oxygen therapy?

Long-term oxygen therapy (LTOT) used for more than 15 hours a day is thought to reduce mortality among patients with COPD and severe resting hypoxemia.^15-18 More recent studies have failed to show similar beneficial effects of LTOT. A recent study examined the effects of LTOT in randomized fashion and determined that supplemental oxygen for patients with stable COPD and resting or exercise-induced moderate desaturation did not affect the time to death or first hospitalization, time to first COPD exacerbation, time to first hospitalization for a COPD exacerbation, the rate of all hospitalizations, the rate of all COPD exacerbations, or changes in measures of quality of life, depression, anxiety, or functional status.¹⁹

Our patient is currently on long-term oxygen therapy and in spite of some uncertainty as to its benefit, it is prudent to order oxygen therapy until further clarification is available.

What is the role of pulmonary rehabilitation?

Pulmonary rehabilitation is an established treatment for patients with chronic lung disease.²⁰ Benefits include improvement in exercise tolerance, symptoms, and quality of life, with a reduction in the use of health care resources.²¹ A Spanish population-based cohort study that looked at the influence of regular physical activity on COPD showed that patients who reported low, moderate, or high physical activity had a lower risk of COPD admissions and all-cause mortality than patients with very low physical activity after adjusting for all confounders.²²

As previously mentioned, patients in GOLD categories B, C, and D should be offered pulmonary rehabilitation as part of their treatment.²³ The ideal patient is one who is not too sick to undergo rehabilitation and is motivated to improve his or her quality of life.

What is the current scope of lung transplantation in the management of severe COPD?

There is an indisputable role for lung transplantation in end-stage COPD. However, lung transplantation does not benefit all COPD patients. There is a subset of patients for whom the treatment provides a survival benefit. It has been reported that 79% of patients with an FEV₁ < 16% predicted will survive at least 1 additional year after transplant, but only 11% of patients with an FEV₁ > 25% will do so.²⁴ The pre-transplant BODE (body mass index, airflow obstruction/FEV₁, dyspnea, and exercise capacity) index score is used to identify patients who will benefit from lung transplantation.^25,26 International guidelines for the selection of lung transplant candidates identify the following patient characteristics:²⁷

• The disease is progressive, despite maximal treatment including medication, pulmonary rehabilitation, and oxygen therapy;
• The patient is not a candidate for endoscopic or surgical LVRS;
• BODE index is 5 to 6;
• The PCO₂ is greater than 50 mm Hg (6.6 kPa) and/or PO₂ is less than 60 mm Hg (8 kPa);
• FEV₁ is 25% predicted.

The perioperative mortality of lung transplantation surgery has been reduced to less than 10%. Risk of complications from surgery in the perioperative period, such as bronchial dehiscence, infectious complications, and acute rejection, have also been reduced but do occur. Chronic allograft dysfunction and the risk of lung cancer in cases of single lung transplant should be discussed with the patient before surgery.²⁸

How can we incorporate palliative care into the management plan for patients with COPD?

Among patients with end-stage COPD on home oxygen therapy who have required mechanical ventilation for an exacerbation, only 55% are alive at 1 year.²⁹ COPD patients at high risk of death within the next year of life as well as patients with refractory symptoms and unmet needs are candidates for early palliative care. Palliative care and palliative care specialists can aid in reducing symptom burden and improving quality of life among these patients and their family members, and palliative care is recommended by multiple international societies for patients with advanced COPD.^30,31 In spite of these recommendations, the utilization of palliative care resources has been dismally low.^32,33 Improving physician-patient communication regarding palliative services and patients’ unmet care needs will help ensure that COPD patients receive adequate palliative care services at the appropriate time.

Conclusion

COPD is a leading cause of morbidity and mortality in the United States and represents a significant economic burden for both individuals and society. The goals in COPD management are to provide symptom relief, improve the quality of life, preserve lung function, and reduce the frequency of exacerbations and mortality. COPD management is guided by disease severity that is measured using the GOLD multimodal staging system and requires a multidisciplinary approach. Several classes of medication are available for treatment, and a step-wise approach should be applied in building an effective pharmacologic regimen. In addition to pharmacologic therapies, nonpharmacologic therapies, including smoking cessation, vaccinations, proper nutrition, and maintaining physical activity, are an important part of long-term management. Those who continue to be symptomatic despite appropriate maximal therapy may be candidates for lung volume reduction. Palliative care services for COPD patients, which can aid in reducing symptom burden and improving quality of life, should not be overlooked.

Case Presentation

A 65-year-old man with severe chronic obstructive disease (COPD; forced expiratory volume in 1 second/forced vital capacity ratio [FEV₁/FVC], 27; FEV₁ 25% of predicted; residual volume 170% of predicted for his age and height) was seen in the pulmonary clinic. His medications include a long-acting beta agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination that he uses twice daily as advised. He uses his rescue albuterol inhaler roughly once a week. The patient complains of severe disabling shortness of breath with exertion and severe limitation of his quality of life because of his inability to lead a normal active life. He is on 2 L/min of oxygen at all times. He has received pulmonary rehabilitation in hopes of improving his quality of life but can only climb a flight of stairs before he must stop to rest. He asks about options but does not want to consider lung transplantation today. His most recent chest computed tomography (CT) scan demonstrates upper lobe predominant emphysematous changes with no masses or nodules.

What are the patient's options at this time?

Lung volume reduction surgery (LVRS) attempts to reduce space-occupying severely diseased, hyperexpanded lung, thus allowing the relatively normal adjoining lung parenchyma to expand into the vacated space and function effectively.¹ Hence, such therapies are suitable for patients with emphysematous lungs and not those with bronchitic-predominant COPD. LVRS offers a greater chance of improvement in exercise capacity, lung function, quality of life, and dyspnea in the correctly chosen patient population, as compared with pharmacologic management alone.² However, the procedure is associated with risks, including higher short-term morbidity and mortality.² Patients with predominantly upper-lobe emphysema and a low maximal workload after rehabilitation were noted to have lower mortality, a greater probability of improvement in exercise capacity, and a greater probability of improvement in symptoms if they underwent surgery compared to medical therapy alone.² On the contrary, patients with predominantly non–upper-lobe emphysema and a high maximal workload after rehabilitation had higher mortality if they underwent surgery compared to receiving medical therapy alone.² Thus, a subgroup of patients with homogeneous emphysema symmetrically affecting the upper and lower lobes are considered to be unlikely to benefit from this surgery.^2,3

Valves and other methods of lung volume reduction such as coils, sealants, intrapulmonary vents, and thermal vapor in the bronchi or subsegmental airways have emerged as new techniques for nonsurgical lung volume reduction.^4-9 Endobronchial-valve therapy is associated with improvement in lung function and with clinical benefits that are greatest in the presence of heterogeneous lung involvement. This works by the same principle as LVRS, by reduction of the most severely diseased lung units, expansion of the more viable, less emphysematous lung results in substantial improvements in lung mechanics.^10,11 The most important complications of this procedure include pneumonia, pneumothorax, hemoptysis, and increased frequency of COPD exacerbation in the following 30 days. The fact that a high-heterogeneity subgroup had greater improvements in both the FEV₁ and distance on the 6-minute walk test than did patients with lower heterogeneity supports the use of quantitative high-resolution computed tomography (HRCT) in selecting patients for endobronchial-valve therapy.¹² The HRCT scans also help in identifying those with complete fissures, a marker of lack of collateral ventilation (CV+) between different lobes. Presence of CV+ state predicts failure of endobronchial valve and all forms of endoscopic LVRS.¹³ Bronchoscopic thermal vapor ablation (BTVA) therapy can potentially work on a subsegmental level and be successful for treatment of emphysema with lack of intact fissures on CT scans. Other methods that have the potential to be effective in those with collateral ventilation would be endoscopic coil therapy and polymeric lung volume reduction.^11,14 Unfortunately, there are no randomized controlled trial data demonstrating clinically meaningful improvement following coil therapy or polymeric lung volume reduction in this CV+ patient population. Vapor therapy is perhaps the only technique that has been found to be effective in upper lobe predominant emphysema even with CV+ status.¹³

Our patient has evidence of air trapping and emphysema based on a high residual volume. A CT scan of the chest can determine the nature of the emphysema (heterogeneous versus homogenous) and based on these findings, further determination of the best strategy for lung volume reduction can be made.

Is there a role for long-term oxygen therapy?

Long-term oxygen therapy (LTOT) used for more than 15 hours a day is thought to reduce mortality among patients with COPD and severe resting hypoxemia.^15-18 More recent studies have failed to show similar beneficial effects of LTOT. A recent study examined the effects of LTOT in randomized fashion and determined that supplemental oxygen for patients with stable COPD and resting or exercise-induced moderate desaturation did not affect the time to death or first hospitalization, time to first COPD exacerbation, time to first hospitalization for a COPD exacerbation, the rate of all hospitalizations, the rate of all COPD exacerbations, or changes in measures of quality of life, depression, anxiety, or functional status.¹⁹

Our patient is currently on long-term oxygen therapy and in spite of some uncertainty as to its benefit, it is prudent to order oxygen therapy until further clarification is available.

What is the role of pulmonary rehabilitation?

Pulmonary rehabilitation is an established treatment for patients with chronic lung disease.²⁰ Benefits include improvement in exercise tolerance, symptoms, and quality of life, with a reduction in the use of health care resources.²¹ A Spanish population-based cohort study that looked at the influence of regular physical activity on COPD showed that patients who reported low, moderate, or high physical activity had a lower risk of COPD admissions and all-cause mortality than patients with very low physical activity after adjusting for all confounders.²²

As previously mentioned, patients in GOLD categories B, C, and D should be offered pulmonary rehabilitation as part of their treatment.²³ The ideal patient is one who is not too sick to undergo rehabilitation and is motivated to improve his or her quality of life.

What is the current scope of lung transplantation in the management of severe COPD?

There is an indisputable role for lung transplantation in end-stage COPD. However, lung transplantation does not benefit all COPD patients. There is a subset of patients for whom the treatment provides a survival benefit. It has been reported that 79% of patients with an FEV₁ < 16% predicted will survive at least 1 additional year after transplant, but only 11% of patients with an FEV₁ > 25% will do so.²⁴ The pre-transplant BODE (body mass index, airflow obstruction/FEV₁, dyspnea, and exercise capacity) index score is used to identify patients who will benefit from lung transplantation.^25,26 International guidelines for the selection of lung transplant candidates identify the following patient characteristics:²⁷

• The disease is progressive, despite maximal treatment including medication, pulmonary rehabilitation, and oxygen therapy;
• The patient is not a candidate for endoscopic or surgical LVRS;
• BODE index is 5 to 6;
• The PCO₂ is greater than 50 mm Hg (6.6 kPa) and/or PO₂ is less than 60 mm Hg (8 kPa);
• FEV₁ is 25% predicted.

The perioperative mortality of lung transplantation surgery has been reduced to less than 10%. Risk of complications from surgery in the perioperative period, such as bronchial dehiscence, infectious complications, and acute rejection, have also been reduced but do occur. Chronic allograft dysfunction and the risk of lung cancer in cases of single lung transplant should be discussed with the patient before surgery.²⁸

How can we incorporate palliative care into the management plan for patients with COPD?

Among patients with end-stage COPD on home oxygen therapy who have required mechanical ventilation for an exacerbation, only 55% are alive at 1 year.²⁹ COPD patients at high risk of death within the next year of life as well as patients with refractory symptoms and unmet needs are candidates for early palliative care. Palliative care and palliative care specialists can aid in reducing symptom burden and improving quality of life among these patients and their family members, and palliative care is recommended by multiple international societies for patients with advanced COPD.^30,31 In spite of these recommendations, the utilization of palliative care resources has been dismally low.^32,33 Improving physician-patient communication regarding palliative services and patients’ unmet care needs will help ensure that COPD patients receive adequate palliative care services at the appropriate time.

Conclusion

COPD is a leading cause of morbidity and mortality in the United States and represents a significant economic burden for both individuals and society. The goals in COPD management are to provide symptom relief, improve the quality of life, preserve lung function, and reduce the frequency of exacerbations and mortality. COPD management is guided by disease severity that is measured using the GOLD multimodal staging system and requires a multidisciplinary approach. Several classes of medication are available for treatment, and a step-wise approach should be applied in building an effective pharmacologic regimen. In addition to pharmacologic therapies, nonpharmacologic therapies, including smoking cessation, vaccinations, proper nutrition, and maintaining physical activity, are an important part of long-term management. Those who continue to be symptomatic despite appropriate maximal therapy may be candidates for lung volume reduction. Palliative care services for COPD patients, which can aid in reducing symptom burden and improving quality of life, should not be overlooked.

Case Presentation

A 65-year-old man with severe chronic obstructive disease (COPD; forced expiratory volume in 1 second/forced vital capacity ratio [FEV₁/FVC], 27; FEV₁ 25% of predicted; residual volume 170% of predicted for his age and height) was seen in the pulmonary clinic. His medications include a long-acting beta agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination that he uses twice daily as advised. He uses his rescue albuterol inhaler roughly once a week. The patient complains of severe disabling shortness of breath with exertion and severe limitation of his quality of life because of his inability to lead a normal active life. He is on 2 L/min of oxygen at all times. He has received pulmonary rehabilitation in hopes of improving his quality of life but can only climb a flight of stairs before he must stop to rest. He asks about options but does not want to consider lung transplantation today. His most recent chest computed tomography (CT) scan demonstrates upper lobe predominant emphysematous changes with no masses or nodules.

What are the patient's options at this time?

Lung volume reduction surgery (LVRS) attempts to reduce space-occupying severely diseased, hyperexpanded lung, thus allowing the relatively normal adjoining lung parenchyma to expand into the vacated space and function effectively.¹ Hence, such therapies are suitable for patients with emphysematous lungs and not those with bronchitic-predominant COPD. LVRS offers a greater chance of improvement in exercise capacity, lung function, quality of life, and dyspnea in the correctly chosen patient population, as compared with pharmacologic management alone.² However, the procedure is associated with risks, including higher short-term morbidity and mortality.² Patients with predominantly upper-lobe emphysema and a low maximal workload after rehabilitation were noted to have lower mortality, a greater probability of improvement in exercise capacity, and a greater probability of improvement in symptoms if they underwent surgery compared to medical therapy alone.² On the contrary, patients with predominantly non–upper-lobe emphysema and a high maximal workload after rehabilitation had higher mortality if they underwent surgery compared to receiving medical therapy alone.² Thus, a subgroup of patients with homogeneous emphysema symmetrically affecting the upper and lower lobes are considered to be unlikely to benefit from this surgery.^2,3

Valves and other methods of lung volume reduction such as coils, sealants, intrapulmonary vents, and thermal vapor in the bronchi or subsegmental airways have emerged as new techniques for nonsurgical lung volume reduction.^4-9 Endobronchial-valve therapy is associated with improvement in lung function and with clinical benefits that are greatest in the presence of heterogeneous lung involvement. This works by the same principle as LVRS, by reduction of the most severely diseased lung units, expansion of the more viable, less emphysematous lung results in substantial improvements in lung mechanics.^10,11 The most important complications of this procedure include pneumonia, pneumothorax, hemoptysis, and increased frequency of COPD exacerbation in the following 30 days. The fact that a high-heterogeneity subgroup had greater improvements in both the FEV₁ and distance on the 6-minute walk test than did patients with lower heterogeneity supports the use of quantitative high-resolution computed tomography (HRCT) in selecting patients for endobronchial-valve therapy.¹² The HRCT scans also help in identifying those with complete fissures, a marker of lack of collateral ventilation (CV+) between different lobes. Presence of CV+ state predicts failure of endobronchial valve and all forms of endoscopic LVRS.¹³ Bronchoscopic thermal vapor ablation (BTVA) therapy can potentially work on a subsegmental level and be successful for treatment of emphysema with lack of intact fissures on CT scans. Other methods that have the potential to be effective in those with collateral ventilation would be endoscopic coil therapy and polymeric lung volume reduction.^11,14 Unfortunately, there are no randomized controlled trial data demonstrating clinically meaningful improvement following coil therapy or polymeric lung volume reduction in this CV+ patient population. Vapor therapy is perhaps the only technique that has been found to be effective in upper lobe predominant emphysema even with CV+ status.¹³

Our patient has evidence of air trapping and emphysema based on a high residual volume. A CT scan of the chest can determine the nature of the emphysema (heterogeneous versus homogenous) and based on these findings, further determination of the best strategy for lung volume reduction can be made.

Is there a role for long-term oxygen therapy?

Long-term oxygen therapy (LTOT) used for more than 15 hours a day is thought to reduce mortality among patients with COPD and severe resting hypoxemia.^15-18 More recent studies have failed to show similar beneficial effects of LTOT. A recent study examined the effects of LTOT in randomized fashion and determined that supplemental oxygen for patients with stable COPD and resting or exercise-induced moderate desaturation did not affect the time to death or first hospitalization, time to first COPD exacerbation, time to first hospitalization for a COPD exacerbation, the rate of all hospitalizations, the rate of all COPD exacerbations, or changes in measures of quality of life, depression, anxiety, or functional status.¹⁹

Our patient is currently on long-term oxygen therapy and in spite of some uncertainty as to its benefit, it is prudent to order oxygen therapy until further clarification is available.

What is the role of pulmonary rehabilitation?

Pulmonary rehabilitation is an established treatment for patients with chronic lung disease.²⁰ Benefits include improvement in exercise tolerance, symptoms, and quality of life, with a reduction in the use of health care resources.²¹ A Spanish population-based cohort study that looked at the influence of regular physical activity on COPD showed that patients who reported low, moderate, or high physical activity had a lower risk of COPD admissions and all-cause mortality than patients with very low physical activity after adjusting for all confounders.²²

As previously mentioned, patients in GOLD categories B, C, and D should be offered pulmonary rehabilitation as part of their treatment.²³ The ideal patient is one who is not too sick to undergo rehabilitation and is motivated to improve his or her quality of life.

What is the current scope of lung transplantation in the management of severe COPD?

There is an indisputable role for lung transplantation in end-stage COPD. However, lung transplantation does not benefit all COPD patients. There is a subset of patients for whom the treatment provides a survival benefit. It has been reported that 79% of patients with an FEV₁ < 16% predicted will survive at least 1 additional year after transplant, but only 11% of patients with an FEV₁ > 25% will do so.²⁴ The pre-transplant BODE (body mass index, airflow obstruction/FEV₁, dyspnea, and exercise capacity) index score is used to identify patients who will benefit from lung transplantation.^25,26 International guidelines for the selection of lung transplant candidates identify the following patient characteristics:²⁷

• The disease is progressive, despite maximal treatment including medication, pulmonary rehabilitation, and oxygen therapy;
• The patient is not a candidate for endoscopic or surgical LVRS;
• BODE index is 5 to 6;
• The PCO₂ is greater than 50 mm Hg (6.6 kPa) and/or PO₂ is less than 60 mm Hg (8 kPa);
• FEV₁ is 25% predicted.

The perioperative mortality of lung transplantation surgery has been reduced to less than 10%. Risk of complications from surgery in the perioperative period, such as bronchial dehiscence, infectious complications, and acute rejection, have also been reduced but do occur. Chronic allograft dysfunction and the risk of lung cancer in cases of single lung transplant should be discussed with the patient before surgery.²⁸

How can we incorporate palliative care into the management plan for patients with COPD?

Among patients with end-stage COPD on home oxygen therapy who have required mechanical ventilation for an exacerbation, only 55% are alive at 1 year.²⁹ COPD patients at high risk of death within the next year of life as well as patients with refractory symptoms and unmet needs are candidates for early palliative care. Palliative care and palliative care specialists can aid in reducing symptom burden and improving quality of life among these patients and their family members, and palliative care is recommended by multiple international societies for patients with advanced COPD.^30,31 In spite of these recommendations, the utilization of palliative care resources has been dismally low.^32,33 Improving physician-patient communication regarding palliative services and patients’ unmet care needs will help ensure that COPD patients receive adequate palliative care services at the appropriate time.

Conclusion

COPD is a leading cause of morbidity and mortality in the United States and represents a significant economic burden for both individuals and society. The goals in COPD management are to provide symptom relief, improve the quality of life, preserve lung function, and reduce the frequency of exacerbations and mortality. COPD management is guided by disease severity that is measured using the GOLD multimodal staging system and requires a multidisciplinary approach. Several classes of medication are available for treatment, and a step-wise approach should be applied in building an effective pharmacologic regimen. In addition to pharmacologic therapies, nonpharmacologic therapies, including smoking cessation, vaccinations, proper nutrition, and maintaining physical activity, are an important part of long-term management. Those who continue to be symptomatic despite appropriate maximal therapy may be candidates for lung volume reduction. Palliative care services for COPD patients, which can aid in reducing symptom burden and improving quality of life, should not be overlooked.

ILLUSTRATIVE CASE

Penny E is a 48-year-old woman with a history of asthma who presents with wheezing and respiratory distress. There are no clinical signs of deep vein thrombosis or hemoptysis. Pulmonary embolism (PE) is not your most likely diagnosis, but it is included in the differential, so you order a D-dimer concentration and it returns at 700 ng/mL. Should you order computed tomography pulmonary angiography (CTPA) to evaluate for PE?

PE is the third most common type of cardiovascular disease after coronary artery disease and stroke, with an estimated incidence in the United States of 1-2 people/1000 population and a 30-day mortality rate between 10% and 30%.² Improved adherence to a clinical decision support system has been shown to significantly decrease the number of diagnostic tests performed and the number of diagnostic failures.³

The use of a diagnostic algorithm that includes the Wells’ criteria and a D-dimer concentration can exclude PE without CTPA in 20% to 30% of patients.⁴ However, due to the complexity of the algorithm and insufficient time in busy emergency departments, adherence to recommended diagnostic strategies is variable.⁵

Further, it is common for a D-dimer test to be obtained before clinical assessment by a provider.⁶ A fixed cutoff D-dimer concentration of 500 ng/mL is commonly used despite an absolute reduction of 11.6% (95% confidence interval [CI], 10.5-12.9) in the need for CTPA using an age-adjusted D-dimer concentration threshold (age × 10 ng/mL for patients > 50 years).⁷

Three items of the original Wells’ criteria—clinical signs of deep vein thrombosis, hemoptysis, and whether PE is the most likely diagnosis—are the most predictive for PE.⁸ The development of a more efficient algorithm based on these 3 items that uses differential D-dimer concentration thresholds could retain sensitivity and decrease unnecessary CTPAs. Decreasing CTPAs would avoid contrast-induced nephropathy and decrease cancers associated with radiation exposure.^9-11 Significant cost savings could also be achieved, as the estimated cost of one CTPA is $648, while a D-dimer concentration is estimated to cost $14.¹²

STUDY SUMMARY

Simplified algorithm diagnoses PE with fewer CTPAs

The YEARS study was a prospective cohort study conducted in 12 hospitals in the Netherlands that included 3616 patients with clinically suspected PE.¹ After excluding 151 patients who met exclusion criteria (life expectancy < 3 months, ongoing anticoagulation treatment, pregnancy, and contraindication to CTPA), investigators managed 3465 study patients according to the YEARS algorithm. This algorithm called for obtaining a D-dimer concentration in all patients and assessment using the YEARS clinical decision rule, consisting of 3 items assessed by an attending physician: clinical signs of deep vein thrombosis, hemoptysis, and whether PE was the most likely diagnosis. PE was considered excluded if a patient had no positive YEARS items and a D-dimer concentration < 1000 ng/mL or if the patient had one or more YEARS items and a D-dimer concentration < 500 ng/mL. The primary outcome was venous thromboembolism (VTE) events at 3 months’ follow-up once PE was excluded. The secondary outcome was the number of required CTPAs using the YEARS decision rule compared with the number that would have been required if the Wells’ diagnostic algorithm had been implemented.

Of the 1743 patients who had none of the 3 YEARS items, 1320 had a D-dimer concentration below the 1000 ng/mL threshold. Fifty-five of the 423 who had a D-dimer ≥ 1000 ng/mL had confirmed PE by CTPA. In the 1722 patients who had at least 1 YEARS item, 1391 had a D-dimer concentration ≥ 500 ng/mL threshold; 401 of those 1391 had PE confirmed by CTPA.

Continue to: Eighteen of the 2964 patients...

Eighteen of the 2964 patients who had PE ruled out by the YEARS algorithm at baseline were found to have symptomatic VTE during the follow-up period (0.61%; 95% CI, 0.36-0.96), with 6 patients (0.20%; 95% CI, 0.07-0.44) sustaining a fatal PE. The 3-month incidence of VTE in patients who did not have CTPA was 0.43% (95% CI, 0.17-0.88), which is similar to the 0.34% (0.036-0.96) reported in a previous meta-analysis of the Wells’ rule algorithm.¹³ Overall, fatal PE occurred in 0.3% (95% CI, 0.12-0.78) of patients in the YEARS cohort vs 0.6% (0.4-1.1) in a meta-analysis of studies using standard algorithms.¹⁴

The new diagnostic algorithm reduced the use of CT pulmonary angiography by 14% and produced a cost savings of $309,096.

Using an intention-to-diagnose analysis, 1611 (46%) patients did not have a CTPA indicated by the YEARS algorithm compared with 1174 (34%) using the Wells’ algorithm, for an absolute difference of 13% (95% CI, 10-15) and estimated cost savings of $283,176 in this sample. The per-protocol analysis also had a decrease of CTPA examinations in favor of the YEARS algorithm, ruling out 1651 (48%) patients—a decrease of 14% (95% CI, 12-16) and an estimated savings of $309,096.

WHAT’S NEW

High-level evidence says 14% fewer CTPAs

The YEARS study provides a high level of evidence that a new, simple diagnostic algorithm can reliably and efficiently exclude PE and decrease the need for CTPA by 14% (absolute difference; 95% CI, 12-16) when compared with using the Wells’ rule and fixed D-dimer threshold of < 500 ng/mL.

CAVEATS

No adjusting D-dimer for age

The YEARS criteria does not consider an age-adjusted D-dimer threshold, which has been shown to further decrease CTPA use.⁶ This does not preclude the use of YEARS criteria; applying age-adjusted D-dimer thresholds would have led to an absolute reduction of 8.7% (95% CI, 6.4-11) in CTPAs.⁷

CHALLENGES TO IMPLEMENTATION

None to speak of

We see no challenges to the implementation of this recommendation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

Penny E is a 48-year-old woman with a history of asthma who presents with wheezing and respiratory distress. There are no clinical signs of deep vein thrombosis or hemoptysis. Pulmonary embolism (PE) is not your most likely diagnosis, but it is included in the differential, so you order a D-dimer concentration and it returns at 700 ng/mL. Should you order computed tomography pulmonary angiography (CTPA) to evaluate for PE?

PE is the third most common type of cardiovascular disease after coronary artery disease and stroke, with an estimated incidence in the United States of 1-2 people/1000 population and a 30-day mortality rate between 10% and 30%.² Improved adherence to a clinical decision support system has been shown to significantly decrease the number of diagnostic tests performed and the number of diagnostic failures.³

The use of a diagnostic algorithm that includes the Wells’ criteria and a D-dimer concentration can exclude PE without CTPA in 20% to 30% of patients.⁴ However, due to the complexity of the algorithm and insufficient time in busy emergency departments, adherence to recommended diagnostic strategies is variable.⁵

Further, it is common for a D-dimer test to be obtained before clinical assessment by a provider.⁶ A fixed cutoff D-dimer concentration of 500 ng/mL is commonly used despite an absolute reduction of 11.6% (95% confidence interval [CI], 10.5-12.9) in the need for CTPA using an age-adjusted D-dimer concentration threshold (age × 10 ng/mL for patients > 50 years).⁷

Three items of the original Wells’ criteria—clinical signs of deep vein thrombosis, hemoptysis, and whether PE is the most likely diagnosis—are the most predictive for PE.⁸ The development of a more efficient algorithm based on these 3 items that uses differential D-dimer concentration thresholds could retain sensitivity and decrease unnecessary CTPAs. Decreasing CTPAs would avoid contrast-induced nephropathy and decrease cancers associated with radiation exposure.^9-11 Significant cost savings could also be achieved, as the estimated cost of one CTPA is $648, while a D-dimer concentration is estimated to cost $14.¹²

STUDY SUMMARY

Simplified algorithm diagnoses PE with fewer CTPAs

The YEARS study was a prospective cohort study conducted in 12 hospitals in the Netherlands that included 3616 patients with clinically suspected PE.¹ After excluding 151 patients who met exclusion criteria (life expectancy < 3 months, ongoing anticoagulation treatment, pregnancy, and contraindication to CTPA), investigators managed 3465 study patients according to the YEARS algorithm. This algorithm called for obtaining a D-dimer concentration in all patients and assessment using the YEARS clinical decision rule, consisting of 3 items assessed by an attending physician: clinical signs of deep vein thrombosis, hemoptysis, and whether PE was the most likely diagnosis. PE was considered excluded if a patient had no positive YEARS items and a D-dimer concentration < 1000 ng/mL or if the patient had one or more YEARS items and a D-dimer concentration < 500 ng/mL. The primary outcome was venous thromboembolism (VTE) events at 3 months’ follow-up once PE was excluded. The secondary outcome was the number of required CTPAs using the YEARS decision rule compared with the number that would have been required if the Wells’ diagnostic algorithm had been implemented.

Of the 1743 patients who had none of the 3 YEARS items, 1320 had a D-dimer concentration below the 1000 ng/mL threshold. Fifty-five of the 423 who had a D-dimer ≥ 1000 ng/mL had confirmed PE by CTPA. In the 1722 patients who had at least 1 YEARS item, 1391 had a D-dimer concentration ≥ 500 ng/mL threshold; 401 of those 1391 had PE confirmed by CTPA.

Continue to: Eighteen of the 2964 patients...

Eighteen of the 2964 patients who had PE ruled out by the YEARS algorithm at baseline were found to have symptomatic VTE during the follow-up period (0.61%; 95% CI, 0.36-0.96), with 6 patients (0.20%; 95% CI, 0.07-0.44) sustaining a fatal PE. The 3-month incidence of VTE in patients who did not have CTPA was 0.43% (95% CI, 0.17-0.88), which is similar to the 0.34% (0.036-0.96) reported in a previous meta-analysis of the Wells’ rule algorithm.¹³ Overall, fatal PE occurred in 0.3% (95% CI, 0.12-0.78) of patients in the YEARS cohort vs 0.6% (0.4-1.1) in a meta-analysis of studies using standard algorithms.¹⁴

The new diagnostic algorithm reduced the use of CT pulmonary angiography by 14% and produced a cost savings of $309,096.

Using an intention-to-diagnose analysis, 1611 (46%) patients did not have a CTPA indicated by the YEARS algorithm compared with 1174 (34%) using the Wells’ algorithm, for an absolute difference of 13% (95% CI, 10-15) and estimated cost savings of $283,176 in this sample. The per-protocol analysis also had a decrease of CTPA examinations in favor of the YEARS algorithm, ruling out 1651 (48%) patients—a decrease of 14% (95% CI, 12-16) and an estimated savings of $309,096.

WHAT’S NEW

High-level evidence says 14% fewer CTPAs

The YEARS study provides a high level of evidence that a new, simple diagnostic algorithm can reliably and efficiently exclude PE and decrease the need for CTPA by 14% (absolute difference; 95% CI, 12-16) when compared with using the Wells’ rule and fixed D-dimer threshold of < 500 ng/mL.

CAVEATS

No adjusting D-dimer for age

The YEARS criteria does not consider an age-adjusted D-dimer threshold, which has been shown to further decrease CTPA use.⁶ This does not preclude the use of YEARS criteria; applying age-adjusted D-dimer thresholds would have led to an absolute reduction of 8.7% (95% CI, 6.4-11) in CTPAs.⁷

CHALLENGES TO IMPLEMENTATION

None to speak of

We see no challenges to the implementation of this recommendation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

Penny E is a 48-year-old woman with a history of asthma who presents with wheezing and respiratory distress. There are no clinical signs of deep vein thrombosis or hemoptysis. Pulmonary embolism (PE) is not your most likely diagnosis, but it is included in the differential, so you order a D-dimer concentration and it returns at 700 ng/mL. Should you order computed tomography pulmonary angiography (CTPA) to evaluate for PE?

PE is the third most common type of cardiovascular disease after coronary artery disease and stroke, with an estimated incidence in the United States of 1-2 people/1000 population and a 30-day mortality rate between 10% and 30%.² Improved adherence to a clinical decision support system has been shown to significantly decrease the number of diagnostic tests performed and the number of diagnostic failures.³

The use of a diagnostic algorithm that includes the Wells’ criteria and a D-dimer concentration can exclude PE without CTPA in 20% to 30% of patients.⁴ However, due to the complexity of the algorithm and insufficient time in busy emergency departments, adherence to recommended diagnostic strategies is variable.⁵

Further, it is common for a D-dimer test to be obtained before clinical assessment by a provider.⁶ A fixed cutoff D-dimer concentration of 500 ng/mL is commonly used despite an absolute reduction of 11.6% (95% confidence interval [CI], 10.5-12.9) in the need for CTPA using an age-adjusted D-dimer concentration threshold (age × 10 ng/mL for patients > 50 years).⁷

Three items of the original Wells’ criteria—clinical signs of deep vein thrombosis, hemoptysis, and whether PE is the most likely diagnosis—are the most predictive for PE.⁸ The development of a more efficient algorithm based on these 3 items that uses differential D-dimer concentration thresholds could retain sensitivity and decrease unnecessary CTPAs. Decreasing CTPAs would avoid contrast-induced nephropathy and decrease cancers associated with radiation exposure.^9-11 Significant cost savings could also be achieved, as the estimated cost of one CTPA is $648, while a D-dimer concentration is estimated to cost $14.¹²

STUDY SUMMARY

Simplified algorithm diagnoses PE with fewer CTPAs

The YEARS study was a prospective cohort study conducted in 12 hospitals in the Netherlands that included 3616 patients with clinically suspected PE.¹ After excluding 151 patients who met exclusion criteria (life expectancy < 3 months, ongoing anticoagulation treatment, pregnancy, and contraindication to CTPA), investigators managed 3465 study patients according to the YEARS algorithm. This algorithm called for obtaining a D-dimer concentration in all patients and assessment using the YEARS clinical decision rule, consisting of 3 items assessed by an attending physician: clinical signs of deep vein thrombosis, hemoptysis, and whether PE was the most likely diagnosis. PE was considered excluded if a patient had no positive YEARS items and a D-dimer concentration < 1000 ng/mL or if the patient had one or more YEARS items and a D-dimer concentration < 500 ng/mL. The primary outcome was venous thromboembolism (VTE) events at 3 months’ follow-up once PE was excluded. The secondary outcome was the number of required CTPAs using the YEARS decision rule compared with the number that would have been required if the Wells’ diagnostic algorithm had been implemented.

Of the 1743 patients who had none of the 3 YEARS items, 1320 had a D-dimer concentration below the 1000 ng/mL threshold. Fifty-five of the 423 who had a D-dimer ≥ 1000 ng/mL had confirmed PE by CTPA. In the 1722 patients who had at least 1 YEARS item, 1391 had a D-dimer concentration ≥ 500 ng/mL threshold; 401 of those 1391 had PE confirmed by CTPA.

Continue to: Eighteen of the 2964 patients...

Eighteen of the 2964 patients who had PE ruled out by the YEARS algorithm at baseline were found to have symptomatic VTE during the follow-up period (0.61%; 95% CI, 0.36-0.96), with 6 patients (0.20%; 95% CI, 0.07-0.44) sustaining a fatal PE. The 3-month incidence of VTE in patients who did not have CTPA was 0.43% (95% CI, 0.17-0.88), which is similar to the 0.34% (0.036-0.96) reported in a previous meta-analysis of the Wells’ rule algorithm.¹³ Overall, fatal PE occurred in 0.3% (95% CI, 0.12-0.78) of patients in the YEARS cohort vs 0.6% (0.4-1.1) in a meta-analysis of studies using standard algorithms.¹⁴

The new diagnostic algorithm reduced the use of CT pulmonary angiography by 14% and produced a cost savings of $309,096.

Using an intention-to-diagnose analysis, 1611 (46%) patients did not have a CTPA indicated by the YEARS algorithm compared with 1174 (34%) using the Wells’ algorithm, for an absolute difference of 13% (95% CI, 10-15) and estimated cost savings of $283,176 in this sample. The per-protocol analysis also had a decrease of CTPA examinations in favor of the YEARS algorithm, ruling out 1651 (48%) patients—a decrease of 14% (95% CI, 12-16) and an estimated savings of $309,096.

WHAT’S NEW

High-level evidence says 14% fewer CTPAs

The YEARS study provides a high level of evidence that a new, simple diagnostic algorithm can reliably and efficiently exclude PE and decrease the need for CTPA by 14% (absolute difference; 95% CI, 12-16) when compared with using the Wells’ rule and fixed D-dimer threshold of < 500 ng/mL.

CAVEATS

No adjusting D-dimer for age

The YEARS criteria does not consider an age-adjusted D-dimer threshold, which has been shown to further decrease CTPA use.⁶ This does not preclude the use of YEARS criteria; applying age-adjusted D-dimer thresholds would have led to an absolute reduction of 8.7% (95% CI, 6.4-11) in CTPAs.⁷

CHALLENGES TO IMPLEMENTATION

None to speak of

We see no challenges to the implementation of this recommendation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

The prevalence of allergic disease in the general population is quite high; 8.3% of adults and children have asthma and 11.4% of children have skin allergies.¹ Food allergies are present in 8% of children and 5% of adults,² and up to 10% of anaphylactic reactions in the United States are due to stinging insects.³

Allergy immunotherapy has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.

Moderate-to-severe food and environmental allergies can negatively affect multiple organ systems and significantly impact morbidity and mortality.⁴ Quality of life and the financial well-being of patients with allergic diseases, as well as that of their families, can also be significantly impacted by these conditions.^4,5 High prevalence and burden of disease mandate that family physicians (FPs) stay up-to-date on the full array of treatment options for allergic diseases. What follows are 6 common questions about allergy immunotherapy (AIT) and the evidence-based answers that will help you to identify and treat appropriate candidates, as well as educate them along the way.

IMAGE: © ALICIA BUELOW

Who is a candidate for AIT?

Patients with moderate-to-severe immunoglobulin (Ig)E-mediated allergies whose symptoms are not adequately controlled by medications and allergen trigger avoidance are candidates for AIT.^6-8 Skin prick/puncture testing provides the most reliable and cost-effective confirmation of allergies that are suspected, based on patient history and clinical assessment for allergic symptoms.⁹ Life-threatening reactions to skin prick/puncture testing are rare.⁹ While in vitro (laboratory) testing for IgE levels to specific antigens may be more convenient for patients and less invasive than skin prick/puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.⁹

What constitutes AIT?

AIT is a disease-modifying treatment that, along with allergen avoidance, can provide long-term remission of allergic disease in certain circumstances.^6,7 Consistent gradual exposure to an allergen helps to dampen the inflammatory reaction driven by T cells and B cells, producing clinical tolerance or desensitization that persists after the discontinuation of AIT.⁸ While subcutaneous immunotherapy (SCIT) is the most widely known type of AIT (ie, allergy shots), there are additional ways that AIT can be administered. These include sublingual immunotherapy (SLIT), venom immunotherapy (VIT), and oral immunotherapy (OIT). The selection of the route of administration depends on the exact nature and symptoms of the allergic condition being treated (TABLE^6,8-12).

AIT involves 2 phases

The first phase is the induction or buildup phase during which patients are given gradually increasing amounts of allergen to induce a protective immunologic response.⁶ After 8 to 28 weeks, the maintenance phase begins, during which continued, consistent allergen exposure is designed to prevent relapse of, and facilitate continued remission of, allergy symptoms.⁶ The maintenance phase of AIT can last 24 to 48 months.^6,10 Certain patients may qualify for an expedited AIT regimen called cluster or rush immunotherapy.⁶

While lab testing may be more convenient for patients and less invasive than skin prick/ puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.

Conventional schedules for AIT involve increasing the dose of allergen given at each visit (1-3 doses/wk), whereas rush dosing involves multiple, increasing doses given in a single extended visit to reach therapeutic desensitization faster.⁶ AIT has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.¹⁰

Length of therapy must be individualized

Experts recommend that the length of treatment with AIT be customized for each patient based on the severity of pretreatment allergy symptoms, the benefit experienced with AIT, the inconvenience of AIT to the patient, and the anticipated impact of symptom relapse.^6,10 There are no physiologic symptoms or objective tests that predict which patients will remain in remission after discontinuing AIT; thus, a joint task force of allergy experts suggests that the decision to restart AIT in patients who have a relapse in allergic symptoms should be made based on the same factors used to determine the duration of the maintenance phase.⁶

Continue to: These allergans are appropriate for AIT

Allergens may be described in terms of mechanism and chronicity of exposure. While avoidance of offending allergens is recommended for those who are sensitized, avoidance is not always possible.^6,7,9,13 AIT has been studied as a therapeutic modality to prevent exposure-related symptoms associated with each of the following types of allergens.^6,7,9,11,14

Inhalant allergens circulate in disturbed and undisturbed air and may be seasonal (eg, pollen), perennial (eg, cat/dog allergens), and/or occupational.⁹ They can derive from the indoors (eg, cockroach, cat, dog, dust mite) or outdoors (eg, tree, grass, or weed pollen ),^6,7,9,11 and serve as triggers for many allergic diseases such as allergic rhinitis (AR), allergic rhinoconjunctivitis, allergic dermatitis, and asthma.^7,13

Food allergens. Sensitization to food allergens may produce a range of symptoms.^6,7 One person may experience nothing more than tingling of the lips when eating a peach, while another may experience throat tightness and anaphylaxis due to the aroma of shellfish cooking.

Occupational allergens. Exposure to occupational allergens varies depending on the setting. Those who work in health care or with animals can be exposed to allergens (eg, latex and animal proteins, respectively) that can cause skin or respiratory hypersensitivity reactions. Occupational allergens can also include chemicals; workers in agriculture or housekeeping may be particularly at risk.

Insect allergens. Envenomation by stinging insects of the order Hymenoptera (bees, yellow jackets, hornets, wasps, fire ants) most commonly causes a pruritic, painful local reaction, but patients sensitized to Hymenoptera venom experience systemic allergic reactions that range from mild to life-threatening.^3,6,7

Continue to: When should you use AIT?

Allergic rhinitis (AR). AR can be triggered by exposure to indoor or outdoor inhalant allergens. Research has shown AIT to be an effective treatment for AR and the conjunctivitis caused by inhaled environmental allergens.^15-17 AIT results in improved symptom control and decreased use of rescue medication (standardized mean difference [SMD] -0.32; 95% confidence interval [CI], -0.23 to -0.33, favoring AIT intervention) in patients with seasonal or perennial AR.^15-17

SCIT effectiveness has been demonstrated in sensitized patients who have symptoms associated with pollen, animal allergens, dust mites, and mold/fungi,^15,16 and SCIT may be effective for the treatment of symptoms associated with cockroach exposure.¹¹ SLIT is approved by the US Food and Drug Administration (FDA) for the treatment of several pollen allergens with efficacy rates similar to those of SCIT and with no significant difference in adverse events (AEs).^8,15,16 Direct comparison studies of SCIT and SLIT preparations for treating grass allergy, while of low quality, showed comparable reductions in allergic rhinoconjunctival symptoms.¹⁵

Asthma. AIT (SCIT and SLIT) has been shown to be effective and safe in patients with mild-to-moderate asthma associated with inhalant allergens. Asthma should be controlled prior to initiation of AIT.^6,8,10 Well-known allergic triggers for asthma exacerbation include indoor inhaled allergens (eg, house dust mite, animal dander, cockroach), outdoor inhalant allergens (plants, pollen), and occupational inhaled allergens (silkworm, weevil).^11,13

In one meta-analysis of 796 patients with asthma from 19 different randomized controlled trials, SCIT significantly decreased asthma-related symptom scores (SMD = -0.94; 95% CI, -1.58 to -0.29; P = .004), as well as asthma medication scores (SMD = -1.06; 95% CI, -1.70 to -0.42; P = .001).¹⁸ While AIT has not been shown to improve lung function, meta-analyses have shown that adults with asthma treated with AIT experience fewer/less severe exacerbations and use less rescue medication when compared with those taking placebo.^19,20 Furthermore, studies have shown that SCIT and SLIT reduce asthma symptoms and asthma medication use compared with placebo or usual care in the pediatric population.²⁰

Adults with asthma treated with allergy immunotherapy use less rescue medication when compared to those taking placebo.

As helpful as AIT can be for some patients with mild-to-moderate asthma, patients with severe asthma experience more severe adverse reactions with AIT.²¹ Therefore, most experts recommend against administering AIT to patients with severe asthma.^6,8,21

Continue to: Stinging insects

Stinging insects. VIT is used for patients with hypersensitivity to the venom from insects of the order Hymenoptera (see previous list of insects).^3,11,22 A meta-analysis concluded, based on limited evidence from low-quality studies, that VIT has the potential to substantially reduce the incidence of severe allergic reactions in patients with Hymenoptera sensitivity with 72% of patients benefitting from VIT (number needed to treat [NNT] = 1.4).²² VIT reduces the risk of a systemic reaction, as well as the size and duration of large local reactions (LLRs).^6,22 Immunotherapy for stinging insects also has been shown to improve disease-specific quality of life (risk difference = 1.41 strongly favoring VIT).^6,22

Insect allergens. Research has shown AIT to be an effective therapy for many allergens even though the potency and effectiveness for some allergens are not standardized or regulated.^6,7,11,14 For example, AIT is available for some inhaled insect allergens; however, because the extracts are not standardized, AIT produces inconsistent outcomes.^11,14 As another example, certain occupations lead to exposure to inhaled insect allergens such as silkworm and weevils. AIT is not indicated for either because available silkworm extracts are used only for allergy testing.¹¹ There are no extracts to test for or treat weevil allergy.¹¹

Food. IgE-mediated food allergy can result in oral allergy syndrome, angioedema, urticaria, and/or anaphylaxis.^2,7,8 There is some evidence that AIT raises the threshold of reactivity in children with IgE-mediated food allergies.^6,7,23-25 But the studies available for meta-analyses (some of which involved OIT) were deemed to be of low quality due to a high risk of bias and a small number of participants.^24,25 AIT for food allergies is associated with a substantially increased incidence of moderate adverse reactions, including upper respiratory, gastrointestinal, and skin symptoms, with a probability of 46% during the buildup phase and a number needed to harm (NNH) of 2.1 (95% CI, 1.8-2.5; P < .0001).^6,25 Therefore, experts consider AIT in any form for food hypersensitivity to be investigational.^6,10

Allergen immunotherapy for allergic rhinitis has proven to be effective at improving quality of life and symptom control and decreasing comorbid disease and use of rescue medication.

But preliminary data from a recent phase 3 trial of OIT for peanut allergy involving 499 children and teens are promising; 67.2% tolerated the food challenge of ≥ 600 mg of peanut protein at the completion of peanut OIT without dose-limiting symptoms (difference = 63.2 percentage points; 95% CI, 53-73.3; P < .001).²⁶ More than twice as many participants in the placebo group vs the treatment group experienced AEs that were moderate (59% vs 25%, respectively) or severe (11% vs 5%, respectively).

There are ongoing trials of SCIT, SLIT, and OIT using modified food allergens to make participants less allergic while maintaining immunogenicity.^2,27 Additional trials include adjunctive treatments like probiotics to create safer, more effective options for children with food allergies.^2,27 Keep in mind that children with food allergies often have concomitant allergies (eg, inhalant allergies) that can benefit from AIT.

Continue to: Other clinical practice strategies include...

Other clinical practice strategies include the introduction of extensively heated (baked) milk and egg products, which benefit the majority of milk- and egg-allergic children.^2,28 An American Academy of Allergy, Asthma and Immunology (AAAAI)-sponsored Task Force and the European Academy of Allergy and Clinical Immunology (EAACI) support exclusive breastfeeding for the first 4 to 6 months of life to decrease the risk of developing food allergies.^6,7

Atopic dermatitis (AD). AD is an IgE-mediated skin disease that affects children and adults. AD is associated with asthma, AR, and food allergy.¹³ Early studies showed that AIT reduced topical corticosteroid use and improved the SCORAD (SCORing Atopic Dermatitis; see www.scorad.corti.li/) score.¹⁰ However, Cochrane reviews of studies involving children and adults with AD undergoing AIT via SCIT, SLIT, or OIT routes found that AIT was not effective in treating AD when accounting for the quality and heterogeneity of the studies.^12,29 In addition, there were no significant differences in SCORAD scores.^10,12

Contact allergens. Contact allergens, including plant resins (eg, poison ivy) and metals (eg, nickel) cause local dermatitis through a cell-mediated, delayed hypersensitivity response. AIT is not indicated for contact dermatitis.^6,9

Why use AIT?

First, AIT has been shown to modify disease. Second, because of its disease-modifying properties, AIT may provide cost savings over standard drug treatment in patients with asthma and AR.^17,20,30 In fact, individual studies have demonstrated ≥ 80% cost savings of AIT over standard drug regimens, although meta-analyses have been unable to demonstrate the same.^30,31

In addition, initial studies suggested that AIT might help to prevent the development of new allergen sensitizations.³² One meta-analysis found that AIT decreased the short-term risk of developing asthma in children with AR; however, subsequent studies showed that AIT did not have efficacy in preventing new allergic disease.^31,33

Continue to: How do you administer AIT?

FPs may be asked to administer AIT to their patients. Patients will typically have weekly office visits during the induction phase of AIT and should have appointments every 6 to 12 months during the maintenance phase.^6,8

While allergy immunotherapy has not been shown to improve lung function in patients with asthma, studies have shown that patients experience fewer exacerbations.

Collaboration with an allergy specialist is wise for dosing schedules and possibly for information regarding adverse reactions during administration. It is essential that AIT be administered by clinicians who are knowledgeable about the signs and symptoms of minor allergic reactions (eg, pruritus, mild erythema, and swelling at the administration site) and severe ones (eg, angioedema, shock, anaphylaxis), as well as who have immediate access to emergency medications and resuscitation, should it be needed.^6-8,34

Most (86%) adverse reactions will occur within 30 minutes of administration of AIT; hence, the recommendation is to observe patients for 30 minutes following AIT administration.^6,7,34 Continual training and “mock” severe reaction responses are beneficial for staff administering AIT to ensure appropriate equipment is available and that appropriate procedures are followed. Late-phase reactions can occur and usually present within 6 to 12 hours of administration; thus, it is essential for patients to be educated on the signs and symptoms of adverse reactions and on symptomatic and emergent treatment.^9,34

Experts consider allergy immunotherapy in any form for food hypersensitivity to be investigational.

Rush immunotherapy regimens for inhalant allergens are associated with increased AEs; therefore, pretreatment with antihistamines, leukotriene antagonists, the monoclonal antibody omalizumab, corticosteroids, or combinations of these agents is often used.^6,34 In contrast to inhaled allergens, rush VIT has not been associated with an increased risk of adverse reactions in meta-analyses.^6,22,34 Most experts recommend that AIT be discontinued if anaphylaxis occurs.^8,34

Is AIT safe?

AIT is a proven safe and effective disease-modifying treatment option.^6-8,31,35 Even when AIT is initiated within the season of increased allergen exposure, meta-analyses reveal no increase in adverse events in patients undergoing AIT.³⁵ Given the lack of high-quality evidence confirming the safety of AIT in the following specific situations, both the AAAAI and EAACI have concluded that these conditions/situations are absolute contraindications for AIT due to the risk of severe reactions by activation of underlying disease^8,21,36:

• severe asthma;
• acquired immune deficiency syndrome (AIDS); and
• initiation of AIT during pregnancy.

Continue to: Patients with a history of transplantation...

Patients with a history of transplantation, cancer in remission, human immunodeficiency virus (HIV) without AIDS, and cardiovascular disease have been safely treated with AIT with a < 1.5% incidence of serious adverse events.^6,21,36 It is possible to give patients taking beta-blockers and/or angiotensin converting enzyme inhibitors (ACEIs) AIT with appropriate consideration. Both classes of drugs can interfere with emergency treatment, so one should consider substitution with an agent from another class if possible during AIT.^6,8,20,34 Patients taking ACEIs receiving VIT had substantially increased adverse reactions compared with other forms of AIT; thus, individual risks and benefits must be weighed carefully before initiating VIT.^6,34

Looking ahead

Studies evaluating the indications for AIT in oral allergy syndrome, food allergy, latex allergy, AD, and venom allergy are ongoing.^2,7,10,26 Although the incidence of severe adverse allergy reactions during AIT is rare, there are investigations of using various immune-modifying agents to improve the safety and efficacy of AIT.³⁷ Application of allergen preparation using skin patches, intralymphatic injections, and chemically modified allergens to make them less immunologically reactive are being researched to further improve safety profiles and make AIT less time consuming.³⁸ In Europe and the United States, there is a call for more rigid studies using standardized SLIT preparations. This will allow for an increased number of AIT studies with decreased heterogeneity.

CORRESPONDENCE
Dellyse Bright, MD, Carolinas Medical Center Family Medicine Residency Program, Atrium Health, 2001 Vail Avenue, Suite 400B, Charlotte, NC 28207; [email protected].

The prevalence of allergic disease in the general population is quite high; 8.3% of adults and children have asthma and 11.4% of children have skin allergies.¹ Food allergies are present in 8% of children and 5% of adults,² and up to 10% of anaphylactic reactions in the United States are due to stinging insects.³

Allergy immunotherapy has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.

Moderate-to-severe food and environmental allergies can negatively affect multiple organ systems and significantly impact morbidity and mortality.⁴ Quality of life and the financial well-being of patients with allergic diseases, as well as that of their families, can also be significantly impacted by these conditions.^4,5 High prevalence and burden of disease mandate that family physicians (FPs) stay up-to-date on the full array of treatment options for allergic diseases. What follows are 6 common questions about allergy immunotherapy (AIT) and the evidence-based answers that will help you to identify and treat appropriate candidates, as well as educate them along the way.

IMAGE: © ALICIA BUELOW

Who is a candidate for AIT?

Patients with moderate-to-severe immunoglobulin (Ig)E-mediated allergies whose symptoms are not adequately controlled by medications and allergen trigger avoidance are candidates for AIT.^6-8 Skin prick/puncture testing provides the most reliable and cost-effective confirmation of allergies that are suspected, based on patient history and clinical assessment for allergic symptoms.⁹ Life-threatening reactions to skin prick/puncture testing are rare.⁹ While in vitro (laboratory) testing for IgE levels to specific antigens may be more convenient for patients and less invasive than skin prick/puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.⁹

What constitutes AIT?

AIT is a disease-modifying treatment that, along with allergen avoidance, can provide long-term remission of allergic disease in certain circumstances.^6,7 Consistent gradual exposure to an allergen helps to dampen the inflammatory reaction driven by T cells and B cells, producing clinical tolerance or desensitization that persists after the discontinuation of AIT.⁸ While subcutaneous immunotherapy (SCIT) is the most widely known type of AIT (ie, allergy shots), there are additional ways that AIT can be administered. These include sublingual immunotherapy (SLIT), venom immunotherapy (VIT), and oral immunotherapy (OIT). The selection of the route of administration depends on the exact nature and symptoms of the allergic condition being treated (TABLE^6,8-12).

AIT involves 2 phases

The first phase is the induction or buildup phase during which patients are given gradually increasing amounts of allergen to induce a protective immunologic response.⁶ After 8 to 28 weeks, the maintenance phase begins, during which continued, consistent allergen exposure is designed to prevent relapse of, and facilitate continued remission of, allergy symptoms.⁶ The maintenance phase of AIT can last 24 to 48 months.^6,10 Certain patients may qualify for an expedited AIT regimen called cluster or rush immunotherapy.⁶

While lab testing may be more convenient for patients and less invasive than skin prick/ puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.

Conventional schedules for AIT involve increasing the dose of allergen given at each visit (1-3 doses/wk), whereas rush dosing involves multiple, increasing doses given in a single extended visit to reach therapeutic desensitization faster.⁶ AIT has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.¹⁰

Length of therapy must be individualized

Experts recommend that the length of treatment with AIT be customized for each patient based on the severity of pretreatment allergy symptoms, the benefit experienced with AIT, the inconvenience of AIT to the patient, and the anticipated impact of symptom relapse.^6,10 There are no physiologic symptoms or objective tests that predict which patients will remain in remission after discontinuing AIT; thus, a joint task force of allergy experts suggests that the decision to restart AIT in patients who have a relapse in allergic symptoms should be made based on the same factors used to determine the duration of the maintenance phase.⁶

Continue to: These allergans are appropriate for AIT

Allergens may be described in terms of mechanism and chronicity of exposure. While avoidance of offending allergens is recommended for those who are sensitized, avoidance is not always possible.^6,7,9,13 AIT has been studied as a therapeutic modality to prevent exposure-related symptoms associated with each of the following types of allergens.^6,7,9,11,14

Inhalant allergens circulate in disturbed and undisturbed air and may be seasonal (eg, pollen), perennial (eg, cat/dog allergens), and/or occupational.⁹ They can derive from the indoors (eg, cockroach, cat, dog, dust mite) or outdoors (eg, tree, grass, or weed pollen ),^6,7,9,11 and serve as triggers for many allergic diseases such as allergic rhinitis (AR), allergic rhinoconjunctivitis, allergic dermatitis, and asthma.^7,13

Food allergens. Sensitization to food allergens may produce a range of symptoms.^6,7 One person may experience nothing more than tingling of the lips when eating a peach, while another may experience throat tightness and anaphylaxis due to the aroma of shellfish cooking.

Occupational allergens. Exposure to occupational allergens varies depending on the setting. Those who work in health care or with animals can be exposed to allergens (eg, latex and animal proteins, respectively) that can cause skin or respiratory hypersensitivity reactions. Occupational allergens can also include chemicals; workers in agriculture or housekeeping may be particularly at risk.

Insect allergens. Envenomation by stinging insects of the order Hymenoptera (bees, yellow jackets, hornets, wasps, fire ants) most commonly causes a pruritic, painful local reaction, but patients sensitized to Hymenoptera venom experience systemic allergic reactions that range from mild to life-threatening.^3,6,7

Continue to: When should you use AIT?

Allergic rhinitis (AR). AR can be triggered by exposure to indoor or outdoor inhalant allergens. Research has shown AIT to be an effective treatment for AR and the conjunctivitis caused by inhaled environmental allergens.^15-17 AIT results in improved symptom control and decreased use of rescue medication (standardized mean difference [SMD] -0.32; 95% confidence interval [CI], -0.23 to -0.33, favoring AIT intervention) in patients with seasonal or perennial AR.^15-17

SCIT effectiveness has been demonstrated in sensitized patients who have symptoms associated with pollen, animal allergens, dust mites, and mold/fungi,^15,16 and SCIT may be effective for the treatment of symptoms associated with cockroach exposure.¹¹ SLIT is approved by the US Food and Drug Administration (FDA) for the treatment of several pollen allergens with efficacy rates similar to those of SCIT and with no significant difference in adverse events (AEs).^8,15,16 Direct comparison studies of SCIT and SLIT preparations for treating grass allergy, while of low quality, showed comparable reductions in allergic rhinoconjunctival symptoms.¹⁵

Asthma. AIT (SCIT and SLIT) has been shown to be effective and safe in patients with mild-to-moderate asthma associated with inhalant allergens. Asthma should be controlled prior to initiation of AIT.^6,8,10 Well-known allergic triggers for asthma exacerbation include indoor inhaled allergens (eg, house dust mite, animal dander, cockroach), outdoor inhalant allergens (plants, pollen), and occupational inhaled allergens (silkworm, weevil).^11,13

In one meta-analysis of 796 patients with asthma from 19 different randomized controlled trials, SCIT significantly decreased asthma-related symptom scores (SMD = -0.94; 95% CI, -1.58 to -0.29; P = .004), as well as asthma medication scores (SMD = -1.06; 95% CI, -1.70 to -0.42; P = .001).¹⁸ While AIT has not been shown to improve lung function, meta-analyses have shown that adults with asthma treated with AIT experience fewer/less severe exacerbations and use less rescue medication when compared with those taking placebo.^19,20 Furthermore, studies have shown that SCIT and SLIT reduce asthma symptoms and asthma medication use compared with placebo or usual care in the pediatric population.²⁰

Adults with asthma treated with allergy immunotherapy use less rescue medication when compared to those taking placebo.

As helpful as AIT can be for some patients with mild-to-moderate asthma, patients with severe asthma experience more severe adverse reactions with AIT.²¹ Therefore, most experts recommend against administering AIT to patients with severe asthma.^6,8,21

Continue to: Stinging insects

Stinging insects. VIT is used for patients with hypersensitivity to the venom from insects of the order Hymenoptera (see previous list of insects).^3,11,22 A meta-analysis concluded, based on limited evidence from low-quality studies, that VIT has the potential to substantially reduce the incidence of severe allergic reactions in patients with Hymenoptera sensitivity with 72% of patients benefitting from VIT (number needed to treat [NNT] = 1.4).²² VIT reduces the risk of a systemic reaction, as well as the size and duration of large local reactions (LLRs).^6,22 Immunotherapy for stinging insects also has been shown to improve disease-specific quality of life (risk difference = 1.41 strongly favoring VIT).^6,22

Insect allergens. Research has shown AIT to be an effective therapy for many allergens even though the potency and effectiveness for some allergens are not standardized or regulated.^6,7,11,14 For example, AIT is available for some inhaled insect allergens; however, because the extracts are not standardized, AIT produces inconsistent outcomes.^11,14 As another example, certain occupations lead to exposure to inhaled insect allergens such as silkworm and weevils. AIT is not indicated for either because available silkworm extracts are used only for allergy testing.¹¹ There are no extracts to test for or treat weevil allergy.¹¹

Food. IgE-mediated food allergy can result in oral allergy syndrome, angioedema, urticaria, and/or anaphylaxis.^2,7,8 There is some evidence that AIT raises the threshold of reactivity in children with IgE-mediated food allergies.^6,7,23-25 But the studies available for meta-analyses (some of which involved OIT) were deemed to be of low quality due to a high risk of bias and a small number of participants.^24,25 AIT for food allergies is associated with a substantially increased incidence of moderate adverse reactions, including upper respiratory, gastrointestinal, and skin symptoms, with a probability of 46% during the buildup phase and a number needed to harm (NNH) of 2.1 (95% CI, 1.8-2.5; P < .0001).^6,25 Therefore, experts consider AIT in any form for food hypersensitivity to be investigational.^6,10

Allergen immunotherapy for allergic rhinitis has proven to be effective at improving quality of life and symptom control and decreasing comorbid disease and use of rescue medication.

But preliminary data from a recent phase 3 trial of OIT for peanut allergy involving 499 children and teens are promising; 67.2% tolerated the food challenge of ≥ 600 mg of peanut protein at the completion of peanut OIT without dose-limiting symptoms (difference = 63.2 percentage points; 95% CI, 53-73.3; P < .001).²⁶ More than twice as many participants in the placebo group vs the treatment group experienced AEs that were moderate (59% vs 25%, respectively) or severe (11% vs 5%, respectively).

There are ongoing trials of SCIT, SLIT, and OIT using modified food allergens to make participants less allergic while maintaining immunogenicity.^2,27 Additional trials include adjunctive treatments like probiotics to create safer, more effective options for children with food allergies.^2,27 Keep in mind that children with food allergies often have concomitant allergies (eg, inhalant allergies) that can benefit from AIT.

Continue to: Other clinical practice strategies include...

Other clinical practice strategies include the introduction of extensively heated (baked) milk and egg products, which benefit the majority of milk- and egg-allergic children.^2,28 An American Academy of Allergy, Asthma and Immunology (AAAAI)-sponsored Task Force and the European Academy of Allergy and Clinical Immunology (EAACI) support exclusive breastfeeding for the first 4 to 6 months of life to decrease the risk of developing food allergies.^6,7

Atopic dermatitis (AD). AD is an IgE-mediated skin disease that affects children and adults. AD is associated with asthma, AR, and food allergy.¹³ Early studies showed that AIT reduced topical corticosteroid use and improved the SCORAD (SCORing Atopic Dermatitis; see www.scorad.corti.li/) score.¹⁰ However, Cochrane reviews of studies involving children and adults with AD undergoing AIT via SCIT, SLIT, or OIT routes found that AIT was not effective in treating AD when accounting for the quality and heterogeneity of the studies.^12,29 In addition, there were no significant differences in SCORAD scores.^10,12

Contact allergens. Contact allergens, including plant resins (eg, poison ivy) and metals (eg, nickel) cause local dermatitis through a cell-mediated, delayed hypersensitivity response. AIT is not indicated for contact dermatitis.^6,9

Why use AIT?

First, AIT has been shown to modify disease. Second, because of its disease-modifying properties, AIT may provide cost savings over standard drug treatment in patients with asthma and AR.^17,20,30 In fact, individual studies have demonstrated ≥ 80% cost savings of AIT over standard drug regimens, although meta-analyses have been unable to demonstrate the same.^30,31

In addition, initial studies suggested that AIT might help to prevent the development of new allergen sensitizations.³² One meta-analysis found that AIT decreased the short-term risk of developing asthma in children with AR; however, subsequent studies showed that AIT did not have efficacy in preventing new allergic disease.^31,33

Continue to: How do you administer AIT?

FPs may be asked to administer AIT to their patients. Patients will typically have weekly office visits during the induction phase of AIT and should have appointments every 6 to 12 months during the maintenance phase.^6,8

While allergy immunotherapy has not been shown to improve lung function in patients with asthma, studies have shown that patients experience fewer exacerbations.

Collaboration with an allergy specialist is wise for dosing schedules and possibly for information regarding adverse reactions during administration. It is essential that AIT be administered by clinicians who are knowledgeable about the signs and symptoms of minor allergic reactions (eg, pruritus, mild erythema, and swelling at the administration site) and severe ones (eg, angioedema, shock, anaphylaxis), as well as who have immediate access to emergency medications and resuscitation, should it be needed.^6-8,34

Most (86%) adverse reactions will occur within 30 minutes of administration of AIT; hence, the recommendation is to observe patients for 30 minutes following AIT administration.^6,7,34 Continual training and “mock” severe reaction responses are beneficial for staff administering AIT to ensure appropriate equipment is available and that appropriate procedures are followed. Late-phase reactions can occur and usually present within 6 to 12 hours of administration; thus, it is essential for patients to be educated on the signs and symptoms of adverse reactions and on symptomatic and emergent treatment.^9,34

Experts consider allergy immunotherapy in any form for food hypersensitivity to be investigational.

Rush immunotherapy regimens for inhalant allergens are associated with increased AEs; therefore, pretreatment with antihistamines, leukotriene antagonists, the monoclonal antibody omalizumab, corticosteroids, or combinations of these agents is often used.^6,34 In contrast to inhaled allergens, rush VIT has not been associated with an increased risk of adverse reactions in meta-analyses.^6,22,34 Most experts recommend that AIT be discontinued if anaphylaxis occurs.^8,34

Is AIT safe?

AIT is a proven safe and effective disease-modifying treatment option.^6-8,31,35 Even when AIT is initiated within the season of increased allergen exposure, meta-analyses reveal no increase in adverse events in patients undergoing AIT.³⁵ Given the lack of high-quality evidence confirming the safety of AIT in the following specific situations, both the AAAAI and EAACI have concluded that these conditions/situations are absolute contraindications for AIT due to the risk of severe reactions by activation of underlying disease^8,21,36:

• severe asthma;
• acquired immune deficiency syndrome (AIDS); and
• initiation of AIT during pregnancy.

Continue to: Patients with a history of transplantation...

Patients with a history of transplantation, cancer in remission, human immunodeficiency virus (HIV) without AIDS, and cardiovascular disease have been safely treated with AIT with a < 1.5% incidence of serious adverse events.^6,21,36 It is possible to give patients taking beta-blockers and/or angiotensin converting enzyme inhibitors (ACEIs) AIT with appropriate consideration. Both classes of drugs can interfere with emergency treatment, so one should consider substitution with an agent from another class if possible during AIT.^6,8,20,34 Patients taking ACEIs receiving VIT had substantially increased adverse reactions compared with other forms of AIT; thus, individual risks and benefits must be weighed carefully before initiating VIT.^6,34

Looking ahead

Studies evaluating the indications for AIT in oral allergy syndrome, food allergy, latex allergy, AD, and venom allergy are ongoing.^2,7,10,26 Although the incidence of severe adverse allergy reactions during AIT is rare, there are investigations of using various immune-modifying agents to improve the safety and efficacy of AIT.³⁷ Application of allergen preparation using skin patches, intralymphatic injections, and chemically modified allergens to make them less immunologically reactive are being researched to further improve safety profiles and make AIT less time consuming.³⁸ In Europe and the United States, there is a call for more rigid studies using standardized SLIT preparations. This will allow for an increased number of AIT studies with decreased heterogeneity.

CORRESPONDENCE
Dellyse Bright, MD, Carolinas Medical Center Family Medicine Residency Program, Atrium Health, 2001 Vail Avenue, Suite 400B, Charlotte, NC 28207; [email protected].

The prevalence of allergic disease in the general population is quite high; 8.3% of adults and children have asthma and 11.4% of children have skin allergies.¹ Food allergies are present in 8% of children and 5% of adults,² and up to 10% of anaphylactic reactions in the United States are due to stinging insects.³

Allergy immunotherapy has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.

Moderate-to-severe food and environmental allergies can negatively affect multiple organ systems and significantly impact morbidity and mortality.⁴ Quality of life and the financial well-being of patients with allergic diseases, as well as that of their families, can also be significantly impacted by these conditions.^4,5 High prevalence and burden of disease mandate that family physicians (FPs) stay up-to-date on the full array of treatment options for allergic diseases. What follows are 6 common questions about allergy immunotherapy (AIT) and the evidence-based answers that will help you to identify and treat appropriate candidates, as well as educate them along the way.

IMAGE: © ALICIA BUELOW

Who is a candidate for AIT?

Patients with moderate-to-severe immunoglobulin (Ig)E-mediated allergies whose symptoms are not adequately controlled by medications and allergen trigger avoidance are candidates for AIT.^6-8 Skin prick/puncture testing provides the most reliable and cost-effective confirmation of allergies that are suspected, based on patient history and clinical assessment for allergic symptoms.⁹ Life-threatening reactions to skin prick/puncture testing are rare.⁹ While in vitro (laboratory) testing for IgE levels to specific antigens may be more convenient for patients and less invasive than skin prick/puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.⁹

What constitutes AIT?

AIT is a disease-modifying treatment that, along with allergen avoidance, can provide long-term remission of allergic disease in certain circumstances.^6,7 Consistent gradual exposure to an allergen helps to dampen the inflammatory reaction driven by T cells and B cells, producing clinical tolerance or desensitization that persists after the discontinuation of AIT.⁸ While subcutaneous immunotherapy (SCIT) is the most widely known type of AIT (ie, allergy shots), there are additional ways that AIT can be administered. These include sublingual immunotherapy (SLIT), venom immunotherapy (VIT), and oral immunotherapy (OIT). The selection of the route of administration depends on the exact nature and symptoms of the allergic condition being treated (TABLE^6,8-12).

AIT involves 2 phases

The first phase is the induction or buildup phase during which patients are given gradually increasing amounts of allergen to induce a protective immunologic response.⁶ After 8 to 28 weeks, the maintenance phase begins, during which continued, consistent allergen exposure is designed to prevent relapse of, and facilitate continued remission of, allergy symptoms.⁶ The maintenance phase of AIT can last 24 to 48 months.^6,10 Certain patients may qualify for an expedited AIT regimen called cluster or rush immunotherapy.⁶

While lab testing may be more convenient for patients and less invasive than skin prick/ puncture testing, it is also less sensitive and less reliable at quantifying the severity of sensitization.

Conventional schedules for AIT involve increasing the dose of allergen given at each visit (1-3 doses/wk), whereas rush dosing involves multiple, increasing doses given in a single extended visit to reach therapeutic desensitization faster.⁶ AIT has been shown to produce a 2.7- to 13.7-fold overall improvement in hypersensitivity reactions.¹⁰

Length of therapy must be individualized

Experts recommend that the length of treatment with AIT be customized for each patient based on the severity of pretreatment allergy symptoms, the benefit experienced with AIT, the inconvenience of AIT to the patient, and the anticipated impact of symptom relapse.^6,10 There are no physiologic symptoms or objective tests that predict which patients will remain in remission after discontinuing AIT; thus, a joint task force of allergy experts suggests that the decision to restart AIT in patients who have a relapse in allergic symptoms should be made based on the same factors used to determine the duration of the maintenance phase.⁶

Continue to: These allergans are appropriate for AIT

Allergens may be described in terms of mechanism and chronicity of exposure. While avoidance of offending allergens is recommended for those who are sensitized, avoidance is not always possible.^6,7,9,13 AIT has been studied as a therapeutic modality to prevent exposure-related symptoms associated with each of the following types of allergens.^6,7,9,11,14

Inhalant allergens circulate in disturbed and undisturbed air and may be seasonal (eg, pollen), perennial (eg, cat/dog allergens), and/or occupational.⁹ They can derive from the indoors (eg, cockroach, cat, dog, dust mite) or outdoors (eg, tree, grass, or weed pollen ),^6,7,9,11 and serve as triggers for many allergic diseases such as allergic rhinitis (AR), allergic rhinoconjunctivitis, allergic dermatitis, and asthma.^7,13

Food allergens. Sensitization to food allergens may produce a range of symptoms.^6,7 One person may experience nothing more than tingling of the lips when eating a peach, while another may experience throat tightness and anaphylaxis due to the aroma of shellfish cooking.

Occupational allergens. Exposure to occupational allergens varies depending on the setting. Those who work in health care or with animals can be exposed to allergens (eg, latex and animal proteins, respectively) that can cause skin or respiratory hypersensitivity reactions. Occupational allergens can also include chemicals; workers in agriculture or housekeeping may be particularly at risk.

Insect allergens. Envenomation by stinging insects of the order Hymenoptera (bees, yellow jackets, hornets, wasps, fire ants) most commonly causes a pruritic, painful local reaction, but patients sensitized to Hymenoptera venom experience systemic allergic reactions that range from mild to life-threatening.^3,6,7

Continue to: When should you use AIT?

Allergic rhinitis (AR). AR can be triggered by exposure to indoor or outdoor inhalant allergens. Research has shown AIT to be an effective treatment for AR and the conjunctivitis caused by inhaled environmental allergens.^15-17 AIT results in improved symptom control and decreased use of rescue medication (standardized mean difference [SMD] -0.32; 95% confidence interval [CI], -0.23 to -0.33, favoring AIT intervention) in patients with seasonal or perennial AR.^15-17

SCIT effectiveness has been demonstrated in sensitized patients who have symptoms associated with pollen, animal allergens, dust mites, and mold/fungi,^15,16 and SCIT may be effective for the treatment of symptoms associated with cockroach exposure.¹¹ SLIT is approved by the US Food and Drug Administration (FDA) for the treatment of several pollen allergens with efficacy rates similar to those of SCIT and with no significant difference in adverse events (AEs).^8,15,16 Direct comparison studies of SCIT and SLIT preparations for treating grass allergy, while of low quality, showed comparable reductions in allergic rhinoconjunctival symptoms.¹⁵

Asthma. AIT (SCIT and SLIT) has been shown to be effective and safe in patients with mild-to-moderate asthma associated with inhalant allergens. Asthma should be controlled prior to initiation of AIT.^6,8,10 Well-known allergic triggers for asthma exacerbation include indoor inhaled allergens (eg, house dust mite, animal dander, cockroach), outdoor inhalant allergens (plants, pollen), and occupational inhaled allergens (silkworm, weevil).^11,13

In one meta-analysis of 796 patients with asthma from 19 different randomized controlled trials, SCIT significantly decreased asthma-related symptom scores (SMD = -0.94; 95% CI, -1.58 to -0.29; P = .004), as well as asthma medication scores (SMD = -1.06; 95% CI, -1.70 to -0.42; P = .001).¹⁸ While AIT has not been shown to improve lung function, meta-analyses have shown that adults with asthma treated with AIT experience fewer/less severe exacerbations and use less rescue medication when compared with those taking placebo.^19,20 Furthermore, studies have shown that SCIT and SLIT reduce asthma symptoms and asthma medication use compared with placebo or usual care in the pediatric population.²⁰

Adults with asthma treated with allergy immunotherapy use less rescue medication when compared to those taking placebo.

As helpful as AIT can be for some patients with mild-to-moderate asthma, patients with severe asthma experience more severe adverse reactions with AIT.²¹ Therefore, most experts recommend against administering AIT to patients with severe asthma.^6,8,21

Continue to: Stinging insects

Stinging insects. VIT is used for patients with hypersensitivity to the venom from insects of the order Hymenoptera (see previous list of insects).^3,11,22 A meta-analysis concluded, based on limited evidence from low-quality studies, that VIT has the potential to substantially reduce the incidence of severe allergic reactions in patients with Hymenoptera sensitivity with 72% of patients benefitting from VIT (number needed to treat [NNT] = 1.4).²² VIT reduces the risk of a systemic reaction, as well as the size and duration of large local reactions (LLRs).^6,22 Immunotherapy for stinging insects also has been shown to improve disease-specific quality of life (risk difference = 1.41 strongly favoring VIT).^6,22

Insect allergens. Research has shown AIT to be an effective therapy for many allergens even though the potency and effectiveness for some allergens are not standardized or regulated.^6,7,11,14 For example, AIT is available for some inhaled insect allergens; however, because the extracts are not standardized, AIT produces inconsistent outcomes.^11,14 As another example, certain occupations lead to exposure to inhaled insect allergens such as silkworm and weevils. AIT is not indicated for either because available silkworm extracts are used only for allergy testing.¹¹ There are no extracts to test for or treat weevil allergy.¹¹

Food. IgE-mediated food allergy can result in oral allergy syndrome, angioedema, urticaria, and/or anaphylaxis.^2,7,8 There is some evidence that AIT raises the threshold of reactivity in children with IgE-mediated food allergies.^6,7,23-25 But the studies available for meta-analyses (some of which involved OIT) were deemed to be of low quality due to a high risk of bias and a small number of participants.^24,25 AIT for food allergies is associated with a substantially increased incidence of moderate adverse reactions, including upper respiratory, gastrointestinal, and skin symptoms, with a probability of 46% during the buildup phase and a number needed to harm (NNH) of 2.1 (95% CI, 1.8-2.5; P < .0001).^6,25 Therefore, experts consider AIT in any form for food hypersensitivity to be investigational.^6,10

Allergen immunotherapy for allergic rhinitis has proven to be effective at improving quality of life and symptom control and decreasing comorbid disease and use of rescue medication.

But preliminary data from a recent phase 3 trial of OIT for peanut allergy involving 499 children and teens are promising; 67.2% tolerated the food challenge of ≥ 600 mg of peanut protein at the completion of peanut OIT without dose-limiting symptoms (difference = 63.2 percentage points; 95% CI, 53-73.3; P < .001).²⁶ More than twice as many participants in the placebo group vs the treatment group experienced AEs that were moderate (59% vs 25%, respectively) or severe (11% vs 5%, respectively).

There are ongoing trials of SCIT, SLIT, and OIT using modified food allergens to make participants less allergic while maintaining immunogenicity.^2,27 Additional trials include adjunctive treatments like probiotics to create safer, more effective options for children with food allergies.^2,27 Keep in mind that children with food allergies often have concomitant allergies (eg, inhalant allergies) that can benefit from AIT.

Continue to: Other clinical practice strategies include...

Other clinical practice strategies include the introduction of extensively heated (baked) milk and egg products, which benefit the majority of milk- and egg-allergic children.^2,28 An American Academy of Allergy, Asthma and Immunology (AAAAI)-sponsored Task Force and the European Academy of Allergy and Clinical Immunology (EAACI) support exclusive breastfeeding for the first 4 to 6 months of life to decrease the risk of developing food allergies.^6,7

Atopic dermatitis (AD). AD is an IgE-mediated skin disease that affects children and adults. AD is associated with asthma, AR, and food allergy.¹³ Early studies showed that AIT reduced topical corticosteroid use and improved the SCORAD (SCORing Atopic Dermatitis; see www.scorad.corti.li/) score.¹⁰ However, Cochrane reviews of studies involving children and adults with AD undergoing AIT via SCIT, SLIT, or OIT routes found that AIT was not effective in treating AD when accounting for the quality and heterogeneity of the studies.^12,29 In addition, there were no significant differences in SCORAD scores.^10,12

Contact allergens. Contact allergens, including plant resins (eg, poison ivy) and metals (eg, nickel) cause local dermatitis through a cell-mediated, delayed hypersensitivity response. AIT is not indicated for contact dermatitis.^6,9

Why use AIT?

First, AIT has been shown to modify disease. Second, because of its disease-modifying properties, AIT may provide cost savings over standard drug treatment in patients with asthma and AR.^17,20,30 In fact, individual studies have demonstrated ≥ 80% cost savings of AIT over standard drug regimens, although meta-analyses have been unable to demonstrate the same.^30,31

In addition, initial studies suggested that AIT might help to prevent the development of new allergen sensitizations.³² One meta-analysis found that AIT decreased the short-term risk of developing asthma in children with AR; however, subsequent studies showed that AIT did not have efficacy in preventing new allergic disease.^31,33

Continue to: How do you administer AIT?

FPs may be asked to administer AIT to their patients. Patients will typically have weekly office visits during the induction phase of AIT and should have appointments every 6 to 12 months during the maintenance phase.^6,8

While allergy immunotherapy has not been shown to improve lung function in patients with asthma, studies have shown that patients experience fewer exacerbations.

Collaboration with an allergy specialist is wise for dosing schedules and possibly for information regarding adverse reactions during administration. It is essential that AIT be administered by clinicians who are knowledgeable about the signs and symptoms of minor allergic reactions (eg, pruritus, mild erythema, and swelling at the administration site) and severe ones (eg, angioedema, shock, anaphylaxis), as well as who have immediate access to emergency medications and resuscitation, should it be needed.^6-8,34

Most (86%) adverse reactions will occur within 30 minutes of administration of AIT; hence, the recommendation is to observe patients for 30 minutes following AIT administration.^6,7,34 Continual training and “mock” severe reaction responses are beneficial for staff administering AIT to ensure appropriate equipment is available and that appropriate procedures are followed. Late-phase reactions can occur and usually present within 6 to 12 hours of administration; thus, it is essential for patients to be educated on the signs and symptoms of adverse reactions and on symptomatic and emergent treatment.^9,34

Experts consider allergy immunotherapy in any form for food hypersensitivity to be investigational.

Rush immunotherapy regimens for inhalant allergens are associated with increased AEs; therefore, pretreatment with antihistamines, leukotriene antagonists, the monoclonal antibody omalizumab, corticosteroids, or combinations of these agents is often used.^6,34 In contrast to inhaled allergens, rush VIT has not been associated with an increased risk of adverse reactions in meta-analyses.^6,22,34 Most experts recommend that AIT be discontinued if anaphylaxis occurs.^8,34

Is AIT safe?

AIT is a proven safe and effective disease-modifying treatment option.^6-8,31,35 Even when AIT is initiated within the season of increased allergen exposure, meta-analyses reveal no increase in adverse events in patients undergoing AIT.³⁵ Given the lack of high-quality evidence confirming the safety of AIT in the following specific situations, both the AAAAI and EAACI have concluded that these conditions/situations are absolute contraindications for AIT due to the risk of severe reactions by activation of underlying disease^8,21,36:

• severe asthma;
• acquired immune deficiency syndrome (AIDS); and
• initiation of AIT during pregnancy.

Continue to: Patients with a history of transplantation...

Patients with a history of transplantation, cancer in remission, human immunodeficiency virus (HIV) without AIDS, and cardiovascular disease have been safely treated with AIT with a < 1.5% incidence of serious adverse events.^6,21,36 It is possible to give patients taking beta-blockers and/or angiotensin converting enzyme inhibitors (ACEIs) AIT with appropriate consideration. Both classes of drugs can interfere with emergency treatment, so one should consider substitution with an agent from another class if possible during AIT.^6,8,20,34 Patients taking ACEIs receiving VIT had substantially increased adverse reactions compared with other forms of AIT; thus, individual risks and benefits must be weighed carefully before initiating VIT.^6,34

Looking ahead

Studies evaluating the indications for AIT in oral allergy syndrome, food allergy, latex allergy, AD, and venom allergy are ongoing.^2,7,10,26 Although the incidence of severe adverse allergy reactions during AIT is rare, there are investigations of using various immune-modifying agents to improve the safety and efficacy of AIT.³⁷ Application of allergen preparation using skin patches, intralymphatic injections, and chemically modified allergens to make them less immunologically reactive are being researched to further improve safety profiles and make AIT less time consuming.³⁸ In Europe and the United States, there is a call for more rigid studies using standardized SLIT preparations. This will allow for an increased number of AIT studies with decreased heterogeneity.

CORRESPONDENCE
Dellyse Bright, MD, Carolinas Medical Center Family Medicine Residency Program, Atrium Health, 2001 Vail Avenue, Suite 400B, Charlotte, NC 28207; [email protected].

From Tufts Medical Center, Boston, MA.

Abstract

• Objective: Audits at our academic medical center revealed near 100% compliance with protocols for perioperative venous thromboembolism (VTE) prophylaxis, but recent National Surgical Quality Improvement Program data demonstrated a higher than expected incidence of VTE (observed/expected = 1.32). The objective of this study was to identify potential causes of this discrepancy.
• Design: Retrospective case-control study.
• Setting: Urban academic medical center with high case-mix indices (Medicare approximately 2.4, non-Medicare approximately 2.0).
• Participants: 102 surgical inpatients with VTE (September 2012 to October 2015) matched with controls for age, gender, and type of procedure.
• Measurements: Prevalence of common VTE risk factors, length of stay, number of procedures, index operation times, and postoperative bed rest > 12 hours were assessed. Utilization of and compliance with our VTE risk assessment tool was also investigated.
• Results: Cases underwent more procedures and had longer lengths of stay and index procedures than controls. In addition, cases were more likely to have had > 12 hours of postoperative bed rest and central venous access than controls. Cases had more infections and were more likely to have severe lung disease, thrombophilia, and a history of prior VTE than controls. No differences in body mass index, tobacco use, current or previous malignancy, or VTE risk assessment form use were observed. Overall, care complexity and risk factors were equally important in determining VTE incidence. Our analyses also revealed lack of strict adherence to our VTE risk stratification protocol and frequent use of suboptimal prophylactic regimens.
• Conclusion: Well-accepted risk factors and overall care complexity determine VTE risk. Preventing VTE in high-risk patients requires assiduous attention to detail in VTE risk assessment and in delivery of optimal prophylaxis. Patients at especially high risk may require customized prophylactic regimens.

Keywords: hospital-acquired venous thromboembolic disease; VTE prophylaxis, surgical patients.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are well-recognized causes of morbidity and mortality in surgical patients. Between 350,000 and 600,000 cases of venous thromboembolism (VTE) occur each year in the United States, and it is responsible for approximately 10% of preventable in-hospital fatalities.^1-3 Given VTE’s impact on patients and the healthcare system and the fact that it is preventable, intense effort has been focused on developing more effective prophylactic measures to decrease its incidence.^2-4 In 2008, the surgeon general issued a “call to action” for increased efforts to prevent VTE.⁵

The American College of Chest Physicians (ACCP) guidelines subcategorize patients based on type of surgery. In addition, the ACCP guidelines support the use of a Caprini-based scoring system to aid in risk stratification and improve clinical decision-making (Table 1).^4,6-9 In general, scores ≥ 5 qualify individuals as high risk. Based on their risk category, patients receive mechanical prophylaxis, chemical prophylaxis, or a combination of the 2. Lower-risk patients who are ambulatory typically receive only mechanical prophylaxis while in bed, whereas higher-risk patients receive a combination of mechanical prophylaxis and chemoprophylaxis measures.⁷ In general, low-molecular-weight heparin (40 mg daily) and low-dose unfractionated heparin (5000 units 3 times daily) have been the standard evidence-based options for chemoprophylaxis in surgical patients. Absolute contraindications for prophylaxis include active bleeding and known increased risk of bleeding based on patient- or procedure-specific factors.

Our hospital, a 350-bed academic medical center in downtown Boston, MA, serving a diverse population with a very high case-mix index (2.4 Medicare and 2.0 non-Medicare), has strict protocols for VTE prophylaxis consistent with the ACCP guidelines and based on the Surgical Care Improvement Project (SCIP) measures published in 2006.¹⁰ The SCIP mandates allow for considerable surgeon discretion in the use of chemoprophylaxis for neurosurgical cases and general and orthopedic surgery cases deemed to be at high risk for bleeding. In addition, SCIP requires only that prophylaxis be initiated within 24 hours of surgical end time. Although recent audits revealed nearly 100% compliance with SCIP-mandated protocols, National Surgical Quality Improvement Program (NSQIP) data showed that the incidence of VTE events at our institution was higher than expected (observed/expected [O/E] = 1.32).

In order to determine the reasons for this mismatch between process and outcome performance, we investigated whether there were characteristics of our patient population that contributed to the higher than expected rates of VTE, and we scrutinized our VTE prophylaxis protocol to determine if there were aspects of our process that were also contributory.

Methods

Study Sample

This is a retrospective case-control study of surgical inpatients at our hospital during the period September 2012 to October 2015. Cases were identified as patients diagnosed with a VTE (DVT or PE). Controls were identified from a pool of surgical patients whose courses were not complicated by VTE during the same time frame as the cases and who were matched as closely as possible by procedure code, age, and gender.

Patient and hospital course variables that were analyzed included demographics, comorbidities, length of stay, number of procedures, index operation times, duration of postoperative bed rest, use of mechanical prophylaxis, and type of chemoprophylaxis and time frame within which it was initiated. Data were collected via chart review using International Classification of Diseases-9 and -10 codes to identify surgical cases within the allotted time period who were diagnosed with VTE. Demographic variables included age, sex, and ethnicity. Comorbidities included hypertension, diabetes, coronary artery disease, serious lung disease, previous or current malignancy, documented hypercoagulable state, and previous history of VTE. Body mass index (BMI) was also recorded. The aforementioned disease-specific variables were not matched between the case and control groups, as this data was obtained retrospectively during data collection.

Analysis

Associations between case and matched control were analyzed using the paired t-test for continuous variables and McNemar’s test for categorical variables. P values < 0.05 were considered statistically significant. SAS Enterprise Guide 7.15 (Cary, NC) was used for all statistical analyses.

The requirement for informed consent was waived by our Institutional Review Board, as the study was initially deemed to be a quality improvement project, and all data used for this report were de-identified.

Results

Our retrospective case-control analysis included a sample of 102 surgical patients whose courses were complicated by VTE between September 2012 and October 2015. The cases were distributed among 6 different surgical categories (Figure 1): trauma (20%), cancer (10%), cardiovascular (21%), noncancer neurosurgery (28%), elective orthopedics (11%), and miscellaneous general surgery (10%).

Comparisons between cases and controls in terms of patient demographics and risk factors are shown in Table 2. No statistically significant difference was observed in ethnicity or race between the 2 groups. Overall, cases had more hip/pelvis/leg fractures at presentation (P = 0.0008). The case group also had higher proportions of patients with postoperative bed rest greater than 12 hours (P = 0.009), central venous access (P < 0.0001), infection (P < 0.0001), and lower extremity edema documented during the hospitalization prior to development of DVT (P < 0.0001). Additionally, cases had significantly greater rates of previous VTE (P = 0.0004), inherited or acquired thrombophilia (P = 0.03), history of stroke (P = 0.0003), and severe lung disease, including pneumonia (P = 0.0008). No significant differences were noted between cases and matched controls in BMI (P = 0.43), current tobacco use (P = 0.71), current malignancy (P = 0.80), previous malignancy (P = 0.83), head trauma (P = 0.17), or acute cardiac disease (myocardial infarction or congestive heart failure; P = 0.12).

Variables felt to indicate overall complexity of hospital course for cases as compared to controls are outlined in Table 3. Cases were found to have significantly longer lengths of stay (median, 15.5 days versus 3 days, P < 0.0001). To account for the possibility that the development of VTE contributed to the increased length of stay in the cases, we also looked at the duration between admission date and the date of VTE diagnosis and determined that cases still had a longer length of stay when this was accounted for (median, 7 days versus 3 days, P < 0.0001). A much higher proportion of cases underwent more than 1 procedure compared to controls (P < 0.0001), and cases had significantly longer index operations as compared to controls (P = 0.002).

Seventeen cases received heparin on induction during their index procedure, compared to 23 controls (P = 0.24). Additionally, 63 cases began a prophylaxis regimen within 24 hours of surgery end time, compared to 68 controls (P = 0.24). The chemoprophylactic regimens utilized in cases and in controls are summarized in Figure 2. Of note, only 26 cases and 32 controls received standard prophylactic regimens with no missed doses (heparin 5000 units 3 times daily or enoxaparin 40 mg daily). Additionally, in over half of cases and a third of controls, nonstandard regimens were ordered. Examples of nonstandard regimens included nonstandard heparin or enoxaparin doses, low-dose warfarin, or aspirin alone. In most cases, nonstandard regimens were justified on the basis of high risk for bleeding.

Mechanical prophylaxis with pneumatic sequential compression devices (SCDs) was ordered in 93 (91%) cases and 87 (85%) controls; however, we were unable to accurately document uniform compliance in the use of these devices.

With regard to evaluation of our process measures, we found only 17% of cases and controls combined actually had a VTE risk assessment in their chart, and when it was present, it was often incomplete or was completed inaccurately.

Discussion

The goal of this study was to identify factors (patient characteristics and/or processes of care) that may be contributing to the higher than expected incidence of VTE events at our medical center, despite internal audits suggesting near perfect compliance with SCIP-mandated protocols. We found that in addition to usual risk factors for VTE, an overarching theme of our case cohort was their high complexity of illness. At baseline, these patients had significantly greater rates of stroke, thrombophilia, severe lung disease, infection, and history of VTE than controls. Moreover, the hospital courses of cases were significantly more complex than those of controls, as these patients had more procedures, longer lengths of stay and longer index operations, higher rates of postoperative bed rest exceeding 12 hours, and more prevalent central venous access than controls (Table 2). Several of these risk factors have been found to contribute to VTE development despite compliance with prophylaxis protocols.

Cassidy et al reviewed a cohort of nontrauma general surgery patients who developed VTE despite receiving appropriate prophylaxis and found that both multiple operations and emergency procedures contributed to the failure of VTE prophylaxis.¹¹ Similarly, Wang et al identified several independent risk factors for VTE despite thromboprophylaxis, including central venous access and infection, as well as intensive care unit admission, hospitalization for cranial surgery, and admission from a long-term care facility.¹² While our study did not capture some of these additional factors considered by Wang et al, the presence of risk factors not captured in traditional assessment tools suggests that additional consideration for complex patients is warranted.

In addition to these nonmodifiable patient characteristics, aspects of our VTE prophylaxis processes likely contributed to the higher than expected rate of VTE. While the electronic medical record at our institution does contain a VTE risk assessment tool based on the Caprini score, we found it often is not used at all or is used incorrectly/incompletely, which likely reflects the fact that physicians are neither prompted nor required to complete the assessment prior to prescribing VTE prophylaxis.

There is a significant body of evidence demonstrating that mandatory computerized VTE risk assessments can effectively reduce VTE rates and that improved outcomes occur shortly after implementation. Cassidy et al demonstrated the benefits of instituting a hospital-wide, mandatory, Caprini-based computerized VTE risk assessment that provides prophylaxis/early ambulation recommendations. Two years after implementing this system, they observed an 84% reduction in DVTs (P < 0.001) and a 55% reduction in PEs (P < 0.001).¹³ Nimeri et al had similarly impressive success, achieving a reduction in their NSQIP O/E for PE/DVT in general surgery from 6.00 in 2010 to 0.82 (for DVTs) and 0.78 (for PEs) 5 years after implementation of mandatory VTE risk assessment (though they noted that the most dramatic reduction occurred 1 year after implementation).¹⁴ Additionally, a recent systematic review and meta-analysis by Borab et al found computerized VTE risk assessments to be associated with a significant decrease in VTE events.¹⁵

The risk assessment tool used at our institution is qualitative in nature, and current literature suggests that employing a more quantitative tool may yield improved outcomes. Numerous studies have highlighted the importance of identifying patients at very high risk for VTE, as higher risk may necessitate more careful consideration of their prophylactic regimens. Obi et al found patients with Caprini scores higher than 8 to be at significantly greater risk of developing VTE compared to patients with scores of 7 or 8. Also, patients with scores of 7 or 8 were significantly more likely to have a VTE compared to those with scores of 5 or 6.¹⁶ In another study, Lobastov et al identified Caprini scores of 11 or higher as representing an extremely high-risk category for which standard prophylaxis regimens may not be effective.¹⁷ Thus, while having mandatory risk assessment has been shown to dramatically decrease VTE incidence, it is important to consider the magnitude of the numerical risk score. This is of particular importance at medical centers with high case-mix indices where patients at the highest risk might need to be managed with different prophylactic guidelines.

Another notable aspect of the process at our hospital was the great variation in the types of prophylactic regimens ordered, and the adherence to what was ordered. Only 25.5% of patients were maintained on a standard prophylactic regimen with no missed doses (heparin 5000 every 8 hours or enoxaparin 40 mg daily). Thus, the vast majority of the patients who went on to develop VTE either were prescribed a nontraditional prophylaxis regimen or missed doses of standard agents. The need for secondary surgical procedures or other invasive interventions may explain many, but not all, of the missed doses.

The timing of prophylaxis initiation for our patients was also found to deviate from accepted standards. Only 16.8% of cases received prophylaxis upon induction of anesthesia, and furthermore, 38% of cases did not receive any anticoagulation within 24 hours of their index operation. While this variability in prophylaxis implementation was acceptable within the SCIP guidelines based on “high risk for bleeding” or other considerations, it likely contributed to our suboptimal outcomes. The variations and interruptions in prophylactic regimens speak to barriers that have previously been reported as contributing factors to noncompliance with VTE prophylaxis.¹⁸

Given these known barriers and the observed underutilization and improper use of our risk assessment tool, we have recently changed our surgical admission order sets such that a mandatory quantitative risk assessment must be done for every surgical patient at the time of admission/operation before other orders can be completed. Following completion of the assessment, the physician will be presented with an appropriate standard regimen based on the individual patient’s risk assessment. Early results of our VTE quality improvement project have been satisfying: in the most recent NSQIP semi-annual report, our O/E for VTE was 0.74, placing us in the first decile. Some of these early reports may simply be the product of the Hawthorne effect; however, we are encouraged by the early improvements seen in other research. While we are hopeful that these changes will result in sustainable improvements in outcomes, patients at extremely high risk may require novel weight-based or otherwise customized aggressive prophylactic regimens. Such regimens have already been proposed for arthroplasty and other high-risk patients.

Future research may identify other risk factors not captured by traditional risk assessments. In addition, research should continue to explore the use and efficacy of standard prophylactic regimens in these populations to help determine if they are sufficient. Currently, weight-based low-molecular-weight heparin dosing and alternative regimens employing fondaparinux are under investigation for very-high-risk patients.¹⁹

There were several limitations to the present study. First, due to the retrospective design of our study, we could collect only data that had been uniformly recorded in the charts throughout the study period. Second, we were unable to accurately assess compliance with mechanical prophylaxis. While our chart review showed that the vast majority of cases and controls were ordered to have mechanical prophylaxis, it is impossible to document how often these devices were used appropriately in a retrospective analysis. Anecdotal observation suggests that once patients are out of post-anesthesia or critical care units, SCD use is not standardized. The inability to measure compliance precisely may be leading to an overestimation of our compliance with prophylaxis. Finally, because our study included only patients who underwent surgery at our hospital, our observations may not be generalizable outside our institution.

Conclusion

Our study findings reinforce the importance of attention to detail in VTE risk assessment and in ordering and administering VTE prophylactic regimens, especially in high-risk surgical patients. While we adhered to the SCIP-mandated prophylaxis requirements, the complexity of our patients and our lack of a truly standardized approach to risk assessment and prophylactic regimens resulted in suboptimal outcomes. Stricter and more quantitative mandatory VTE risk assessment, along with highly standardized VTE prophylaxis regimens, are required to achieve optimal outcomes.

Corresponding author: Jason C. DeGiovanni, MS, BA, [email protected].

Financial disclosures: None.

From Tufts Medical Center, Boston, MA.

Abstract

• Objective: Audits at our academic medical center revealed near 100% compliance with protocols for perioperative venous thromboembolism (VTE) prophylaxis, but recent National Surgical Quality Improvement Program data demonstrated a higher than expected incidence of VTE (observed/expected = 1.32). The objective of this study was to identify potential causes of this discrepancy.
• Design: Retrospective case-control study.
• Setting: Urban academic medical center with high case-mix indices (Medicare approximately 2.4, non-Medicare approximately 2.0).
• Participants: 102 surgical inpatients with VTE (September 2012 to October 2015) matched with controls for age, gender, and type of procedure.
• Measurements: Prevalence of common VTE risk factors, length of stay, number of procedures, index operation times, and postoperative bed rest > 12 hours were assessed. Utilization of and compliance with our VTE risk assessment tool was also investigated.
• Results: Cases underwent more procedures and had longer lengths of stay and index procedures than controls. In addition, cases were more likely to have had > 12 hours of postoperative bed rest and central venous access than controls. Cases had more infections and were more likely to have severe lung disease, thrombophilia, and a history of prior VTE than controls. No differences in body mass index, tobacco use, current or previous malignancy, or VTE risk assessment form use were observed. Overall, care complexity and risk factors were equally important in determining VTE incidence. Our analyses also revealed lack of strict adherence to our VTE risk stratification protocol and frequent use of suboptimal prophylactic regimens.
• Conclusion: Well-accepted risk factors and overall care complexity determine VTE risk. Preventing VTE in high-risk patients requires assiduous attention to detail in VTE risk assessment and in delivery of optimal prophylaxis. Patients at especially high risk may require customized prophylactic regimens.

Keywords: hospital-acquired venous thromboembolic disease; VTE prophylaxis, surgical patients.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are well-recognized causes of morbidity and mortality in surgical patients. Between 350,000 and 600,000 cases of venous thromboembolism (VTE) occur each year in the United States, and it is responsible for approximately 10% of preventable in-hospital fatalities.^1-3 Given VTE’s impact on patients and the healthcare system and the fact that it is preventable, intense effort has been focused on developing more effective prophylactic measures to decrease its incidence.^2-4 In 2008, the surgeon general issued a “call to action” for increased efforts to prevent VTE.⁵

The American College of Chest Physicians (ACCP) guidelines subcategorize patients based on type of surgery. In addition, the ACCP guidelines support the use of a Caprini-based scoring system to aid in risk stratification and improve clinical decision-making (Table 1).^4,6-9 In general, scores ≥ 5 qualify individuals as high risk. Based on their risk category, patients receive mechanical prophylaxis, chemical prophylaxis, or a combination of the 2. Lower-risk patients who are ambulatory typically receive only mechanical prophylaxis while in bed, whereas higher-risk patients receive a combination of mechanical prophylaxis and chemoprophylaxis measures.⁷ In general, low-molecular-weight heparin (40 mg daily) and low-dose unfractionated heparin (5000 units 3 times daily) have been the standard evidence-based options for chemoprophylaxis in surgical patients. Absolute contraindications for prophylaxis include active bleeding and known increased risk of bleeding based on patient- or procedure-specific factors.

Our hospital, a 350-bed academic medical center in downtown Boston, MA, serving a diverse population with a very high case-mix index (2.4 Medicare and 2.0 non-Medicare), has strict protocols for VTE prophylaxis consistent with the ACCP guidelines and based on the Surgical Care Improvement Project (SCIP) measures published in 2006.¹⁰ The SCIP mandates allow for considerable surgeon discretion in the use of chemoprophylaxis for neurosurgical cases and general and orthopedic surgery cases deemed to be at high risk for bleeding. In addition, SCIP requires only that prophylaxis be initiated within 24 hours of surgical end time. Although recent audits revealed nearly 100% compliance with SCIP-mandated protocols, National Surgical Quality Improvement Program (NSQIP) data showed that the incidence of VTE events at our institution was higher than expected (observed/expected [O/E] = 1.32).

In order to determine the reasons for this mismatch between process and outcome performance, we investigated whether there were characteristics of our patient population that contributed to the higher than expected rates of VTE, and we scrutinized our VTE prophylaxis protocol to determine if there were aspects of our process that were also contributory.

Methods

Study Sample

This is a retrospective case-control study of surgical inpatients at our hospital during the period September 2012 to October 2015. Cases were identified as patients diagnosed with a VTE (DVT or PE). Controls were identified from a pool of surgical patients whose courses were not complicated by VTE during the same time frame as the cases and who were matched as closely as possible by procedure code, age, and gender.

Patient and hospital course variables that were analyzed included demographics, comorbidities, length of stay, number of procedures, index operation times, duration of postoperative bed rest, use of mechanical prophylaxis, and type of chemoprophylaxis and time frame within which it was initiated. Data were collected via chart review using International Classification of Diseases-9 and -10 codes to identify surgical cases within the allotted time period who were diagnosed with VTE. Demographic variables included age, sex, and ethnicity. Comorbidities included hypertension, diabetes, coronary artery disease, serious lung disease, previous or current malignancy, documented hypercoagulable state, and previous history of VTE. Body mass index (BMI) was also recorded. The aforementioned disease-specific variables were not matched between the case and control groups, as this data was obtained retrospectively during data collection.

Analysis

Associations between case and matched control were analyzed using the paired t-test for continuous variables and McNemar’s test for categorical variables. P values < 0.05 were considered statistically significant. SAS Enterprise Guide 7.15 (Cary, NC) was used for all statistical analyses.

The requirement for informed consent was waived by our Institutional Review Board, as the study was initially deemed to be a quality improvement project, and all data used for this report were de-identified.

Results

Our retrospective case-control analysis included a sample of 102 surgical patients whose courses were complicated by VTE between September 2012 and October 2015. The cases were distributed among 6 different surgical categories (Figure 1): trauma (20%), cancer (10%), cardiovascular (21%), noncancer neurosurgery (28%), elective orthopedics (11%), and miscellaneous general surgery (10%).

Comparisons between cases and controls in terms of patient demographics and risk factors are shown in Table 2. No statistically significant difference was observed in ethnicity or race between the 2 groups. Overall, cases had more hip/pelvis/leg fractures at presentation (P = 0.0008). The case group also had higher proportions of patients with postoperative bed rest greater than 12 hours (P = 0.009), central venous access (P < 0.0001), infection (P < 0.0001), and lower extremity edema documented during the hospitalization prior to development of DVT (P < 0.0001). Additionally, cases had significantly greater rates of previous VTE (P = 0.0004), inherited or acquired thrombophilia (P = 0.03), history of stroke (P = 0.0003), and severe lung disease, including pneumonia (P = 0.0008). No significant differences were noted between cases and matched controls in BMI (P = 0.43), current tobacco use (P = 0.71), current malignancy (P = 0.80), previous malignancy (P = 0.83), head trauma (P = 0.17), or acute cardiac disease (myocardial infarction or congestive heart failure; P = 0.12).

Variables felt to indicate overall complexity of hospital course for cases as compared to controls are outlined in Table 3. Cases were found to have significantly longer lengths of stay (median, 15.5 days versus 3 days, P < 0.0001). To account for the possibility that the development of VTE contributed to the increased length of stay in the cases, we also looked at the duration between admission date and the date of VTE diagnosis and determined that cases still had a longer length of stay when this was accounted for (median, 7 days versus 3 days, P < 0.0001). A much higher proportion of cases underwent more than 1 procedure compared to controls (P < 0.0001), and cases had significantly longer index operations as compared to controls (P = 0.002).

Seventeen cases received heparin on induction during their index procedure, compared to 23 controls (P = 0.24). Additionally, 63 cases began a prophylaxis regimen within 24 hours of surgery end time, compared to 68 controls (P = 0.24). The chemoprophylactic regimens utilized in cases and in controls are summarized in Figure 2. Of note, only 26 cases and 32 controls received standard prophylactic regimens with no missed doses (heparin 5000 units 3 times daily or enoxaparin 40 mg daily). Additionally, in over half of cases and a third of controls, nonstandard regimens were ordered. Examples of nonstandard regimens included nonstandard heparin or enoxaparin doses, low-dose warfarin, or aspirin alone. In most cases, nonstandard regimens were justified on the basis of high risk for bleeding.

Mechanical prophylaxis with pneumatic sequential compression devices (SCDs) was ordered in 93 (91%) cases and 87 (85%) controls; however, we were unable to accurately document uniform compliance in the use of these devices.

With regard to evaluation of our process measures, we found only 17% of cases and controls combined actually had a VTE risk assessment in their chart, and when it was present, it was often incomplete or was completed inaccurately.

Discussion

The goal of this study was to identify factors (patient characteristics and/or processes of care) that may be contributing to the higher than expected incidence of VTE events at our medical center, despite internal audits suggesting near perfect compliance with SCIP-mandated protocols. We found that in addition to usual risk factors for VTE, an overarching theme of our case cohort was their high complexity of illness. At baseline, these patients had significantly greater rates of stroke, thrombophilia, severe lung disease, infection, and history of VTE than controls. Moreover, the hospital courses of cases were significantly more complex than those of controls, as these patients had more procedures, longer lengths of stay and longer index operations, higher rates of postoperative bed rest exceeding 12 hours, and more prevalent central venous access than controls (Table 2). Several of these risk factors have been found to contribute to VTE development despite compliance with prophylaxis protocols.

Cassidy et al reviewed a cohort of nontrauma general surgery patients who developed VTE despite receiving appropriate prophylaxis and found that both multiple operations and emergency procedures contributed to the failure of VTE prophylaxis.¹¹ Similarly, Wang et al identified several independent risk factors for VTE despite thromboprophylaxis, including central venous access and infection, as well as intensive care unit admission, hospitalization for cranial surgery, and admission from a long-term care facility.¹² While our study did not capture some of these additional factors considered by Wang et al, the presence of risk factors not captured in traditional assessment tools suggests that additional consideration for complex patients is warranted.

In addition to these nonmodifiable patient characteristics, aspects of our VTE prophylaxis processes likely contributed to the higher than expected rate of VTE. While the electronic medical record at our institution does contain a VTE risk assessment tool based on the Caprini score, we found it often is not used at all or is used incorrectly/incompletely, which likely reflects the fact that physicians are neither prompted nor required to complete the assessment prior to prescribing VTE prophylaxis.

There is a significant body of evidence demonstrating that mandatory computerized VTE risk assessments can effectively reduce VTE rates and that improved outcomes occur shortly after implementation. Cassidy et al demonstrated the benefits of instituting a hospital-wide, mandatory, Caprini-based computerized VTE risk assessment that provides prophylaxis/early ambulation recommendations. Two years after implementing this system, they observed an 84% reduction in DVTs (P < 0.001) and a 55% reduction in PEs (P < 0.001).¹³ Nimeri et al had similarly impressive success, achieving a reduction in their NSQIP O/E for PE/DVT in general surgery from 6.00 in 2010 to 0.82 (for DVTs) and 0.78 (for PEs) 5 years after implementation of mandatory VTE risk assessment (though they noted that the most dramatic reduction occurred 1 year after implementation).¹⁴ Additionally, a recent systematic review and meta-analysis by Borab et al found computerized VTE risk assessments to be associated with a significant decrease in VTE events.¹⁵

The risk assessment tool used at our institution is qualitative in nature, and current literature suggests that employing a more quantitative tool may yield improved outcomes. Numerous studies have highlighted the importance of identifying patients at very high risk for VTE, as higher risk may necessitate more careful consideration of their prophylactic regimens. Obi et al found patients with Caprini scores higher than 8 to be at significantly greater risk of developing VTE compared to patients with scores of 7 or 8. Also, patients with scores of 7 or 8 were significantly more likely to have a VTE compared to those with scores of 5 or 6.¹⁶ In another study, Lobastov et al identified Caprini scores of 11 or higher as representing an extremely high-risk category for which standard prophylaxis regimens may not be effective.¹⁷ Thus, while having mandatory risk assessment has been shown to dramatically decrease VTE incidence, it is important to consider the magnitude of the numerical risk score. This is of particular importance at medical centers with high case-mix indices where patients at the highest risk might need to be managed with different prophylactic guidelines.

Another notable aspect of the process at our hospital was the great variation in the types of prophylactic regimens ordered, and the adherence to what was ordered. Only 25.5% of patients were maintained on a standard prophylactic regimen with no missed doses (heparin 5000 every 8 hours or enoxaparin 40 mg daily). Thus, the vast majority of the patients who went on to develop VTE either were prescribed a nontraditional prophylaxis regimen or missed doses of standard agents. The need for secondary surgical procedures or other invasive interventions may explain many, but not all, of the missed doses.

The timing of prophylaxis initiation for our patients was also found to deviate from accepted standards. Only 16.8% of cases received prophylaxis upon induction of anesthesia, and furthermore, 38% of cases did not receive any anticoagulation within 24 hours of their index operation. While this variability in prophylaxis implementation was acceptable within the SCIP guidelines based on “high risk for bleeding” or other considerations, it likely contributed to our suboptimal outcomes. The variations and interruptions in prophylactic regimens speak to barriers that have previously been reported as contributing factors to noncompliance with VTE prophylaxis.¹⁸

Given these known barriers and the observed underutilization and improper use of our risk assessment tool, we have recently changed our surgical admission order sets such that a mandatory quantitative risk assessment must be done for every surgical patient at the time of admission/operation before other orders can be completed. Following completion of the assessment, the physician will be presented with an appropriate standard regimen based on the individual patient’s risk assessment. Early results of our VTE quality improvement project have been satisfying: in the most recent NSQIP semi-annual report, our O/E for VTE was 0.74, placing us in the first decile. Some of these early reports may simply be the product of the Hawthorne effect; however, we are encouraged by the early improvements seen in other research. While we are hopeful that these changes will result in sustainable improvements in outcomes, patients at extremely high risk may require novel weight-based or otherwise customized aggressive prophylactic regimens. Such regimens have already been proposed for arthroplasty and other high-risk patients.

Future research may identify other risk factors not captured by traditional risk assessments. In addition, research should continue to explore the use and efficacy of standard prophylactic regimens in these populations to help determine if they are sufficient. Currently, weight-based low-molecular-weight heparin dosing and alternative regimens employing fondaparinux are under investigation for very-high-risk patients.¹⁹

There were several limitations to the present study. First, due to the retrospective design of our study, we could collect only data that had been uniformly recorded in the charts throughout the study period. Second, we were unable to accurately assess compliance with mechanical prophylaxis. While our chart review showed that the vast majority of cases and controls were ordered to have mechanical prophylaxis, it is impossible to document how often these devices were used appropriately in a retrospective analysis. Anecdotal observation suggests that once patients are out of post-anesthesia or critical care units, SCD use is not standardized. The inability to measure compliance precisely may be leading to an overestimation of our compliance with prophylaxis. Finally, because our study included only patients who underwent surgery at our hospital, our observations may not be generalizable outside our institution.

Conclusion

Our study findings reinforce the importance of attention to detail in VTE risk assessment and in ordering and administering VTE prophylactic regimens, especially in high-risk surgical patients. While we adhered to the SCIP-mandated prophylaxis requirements, the complexity of our patients and our lack of a truly standardized approach to risk assessment and prophylactic regimens resulted in suboptimal outcomes. Stricter and more quantitative mandatory VTE risk assessment, along with highly standardized VTE prophylaxis regimens, are required to achieve optimal outcomes.

Corresponding author: Jason C. DeGiovanni, MS, BA, [email protected].

Financial disclosures: None.

From Tufts Medical Center, Boston, MA.

Abstract

• Objective: Audits at our academic medical center revealed near 100% compliance with protocols for perioperative venous thromboembolism (VTE) prophylaxis, but recent National Surgical Quality Improvement Program data demonstrated a higher than expected incidence of VTE (observed/expected = 1.32). The objective of this study was to identify potential causes of this discrepancy.
• Design: Retrospective case-control study.
• Setting: Urban academic medical center with high case-mix indices (Medicare approximately 2.4, non-Medicare approximately 2.0).
• Participants: 102 surgical inpatients with VTE (September 2012 to October 2015) matched with controls for age, gender, and type of procedure.
• Measurements: Prevalence of common VTE risk factors, length of stay, number of procedures, index operation times, and postoperative bed rest > 12 hours were assessed. Utilization of and compliance with our VTE risk assessment tool was also investigated.
• Results: Cases underwent more procedures and had longer lengths of stay and index procedures than controls. In addition, cases were more likely to have had > 12 hours of postoperative bed rest and central venous access than controls. Cases had more infections and were more likely to have severe lung disease, thrombophilia, and a history of prior VTE than controls. No differences in body mass index, tobacco use, current or previous malignancy, or VTE risk assessment form use were observed. Overall, care complexity and risk factors were equally important in determining VTE incidence. Our analyses also revealed lack of strict adherence to our VTE risk stratification protocol and frequent use of suboptimal prophylactic regimens.
• Conclusion: Well-accepted risk factors and overall care complexity determine VTE risk. Preventing VTE in high-risk patients requires assiduous attention to detail in VTE risk assessment and in delivery of optimal prophylaxis. Patients at especially high risk may require customized prophylactic regimens.

Keywords: hospital-acquired venous thromboembolic disease; VTE prophylaxis, surgical patients.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are well-recognized causes of morbidity and mortality in surgical patients. Between 350,000 and 600,000 cases of venous thromboembolism (VTE) occur each year in the United States, and it is responsible for approximately 10% of preventable in-hospital fatalities.^1-3 Given VTE’s impact on patients and the healthcare system and the fact that it is preventable, intense effort has been focused on developing more effective prophylactic measures to decrease its incidence.^2-4 In 2008, the surgeon general issued a “call to action” for increased efforts to prevent VTE.⁵

The American College of Chest Physicians (ACCP) guidelines subcategorize patients based on type of surgery. In addition, the ACCP guidelines support the use of a Caprini-based scoring system to aid in risk stratification and improve clinical decision-making (Table 1).^4,6-9 In general, scores ≥ 5 qualify individuals as high risk. Based on their risk category, patients receive mechanical prophylaxis, chemical prophylaxis, or a combination of the 2. Lower-risk patients who are ambulatory typically receive only mechanical prophylaxis while in bed, whereas higher-risk patients receive a combination of mechanical prophylaxis and chemoprophylaxis measures.⁷ In general, low-molecular-weight heparin (40 mg daily) and low-dose unfractionated heparin (5000 units 3 times daily) have been the standard evidence-based options for chemoprophylaxis in surgical patients. Absolute contraindications for prophylaxis include active bleeding and known increased risk of bleeding based on patient- or procedure-specific factors.

Our hospital, a 350-bed academic medical center in downtown Boston, MA, serving a diverse population with a very high case-mix index (2.4 Medicare and 2.0 non-Medicare), has strict protocols for VTE prophylaxis consistent with the ACCP guidelines and based on the Surgical Care Improvement Project (SCIP) measures published in 2006.¹⁰ The SCIP mandates allow for considerable surgeon discretion in the use of chemoprophylaxis for neurosurgical cases and general and orthopedic surgery cases deemed to be at high risk for bleeding. In addition, SCIP requires only that prophylaxis be initiated within 24 hours of surgical end time. Although recent audits revealed nearly 100% compliance with SCIP-mandated protocols, National Surgical Quality Improvement Program (NSQIP) data showed that the incidence of VTE events at our institution was higher than expected (observed/expected [O/E] = 1.32).

In order to determine the reasons for this mismatch between process and outcome performance, we investigated whether there were characteristics of our patient population that contributed to the higher than expected rates of VTE, and we scrutinized our VTE prophylaxis protocol to determine if there were aspects of our process that were also contributory.

Methods

Study Sample

This is a retrospective case-control study of surgical inpatients at our hospital during the period September 2012 to October 2015. Cases were identified as patients diagnosed with a VTE (DVT or PE). Controls were identified from a pool of surgical patients whose courses were not complicated by VTE during the same time frame as the cases and who were matched as closely as possible by procedure code, age, and gender.

Patient and hospital course variables that were analyzed included demographics, comorbidities, length of stay, number of procedures, index operation times, duration of postoperative bed rest, use of mechanical prophylaxis, and type of chemoprophylaxis and time frame within which it was initiated. Data were collected via chart review using International Classification of Diseases-9 and -10 codes to identify surgical cases within the allotted time period who were diagnosed with VTE. Demographic variables included age, sex, and ethnicity. Comorbidities included hypertension, diabetes, coronary artery disease, serious lung disease, previous or current malignancy, documented hypercoagulable state, and previous history of VTE. Body mass index (BMI) was also recorded. The aforementioned disease-specific variables were not matched between the case and control groups, as this data was obtained retrospectively during data collection.

Analysis

Associations between case and matched control were analyzed using the paired t-test for continuous variables and McNemar’s test for categorical variables. P values < 0.05 were considered statistically significant. SAS Enterprise Guide 7.15 (Cary, NC) was used for all statistical analyses.

The requirement for informed consent was waived by our Institutional Review Board, as the study was initially deemed to be a quality improvement project, and all data used for this report were de-identified.

Results

Our retrospective case-control analysis included a sample of 102 surgical patients whose courses were complicated by VTE between September 2012 and October 2015. The cases were distributed among 6 different surgical categories (Figure 1): trauma (20%), cancer (10%), cardiovascular (21%), noncancer neurosurgery (28%), elective orthopedics (11%), and miscellaneous general surgery (10%).

Comparisons between cases and controls in terms of patient demographics and risk factors are shown in Table 2. No statistically significant difference was observed in ethnicity or race between the 2 groups. Overall, cases had more hip/pelvis/leg fractures at presentation (P = 0.0008). The case group also had higher proportions of patients with postoperative bed rest greater than 12 hours (P = 0.009), central venous access (P < 0.0001), infection (P < 0.0001), and lower extremity edema documented during the hospitalization prior to development of DVT (P < 0.0001). Additionally, cases had significantly greater rates of previous VTE (P = 0.0004), inherited or acquired thrombophilia (P = 0.03), history of stroke (P = 0.0003), and severe lung disease, including pneumonia (P = 0.0008). No significant differences were noted between cases and matched controls in BMI (P = 0.43), current tobacco use (P = 0.71), current malignancy (P = 0.80), previous malignancy (P = 0.83), head trauma (P = 0.17), or acute cardiac disease (myocardial infarction or congestive heart failure; P = 0.12).

Variables felt to indicate overall complexity of hospital course for cases as compared to controls are outlined in Table 3. Cases were found to have significantly longer lengths of stay (median, 15.5 days versus 3 days, P < 0.0001). To account for the possibility that the development of VTE contributed to the increased length of stay in the cases, we also looked at the duration between admission date and the date of VTE diagnosis and determined that cases still had a longer length of stay when this was accounted for (median, 7 days versus 3 days, P < 0.0001). A much higher proportion of cases underwent more than 1 procedure compared to controls (P < 0.0001), and cases had significantly longer index operations as compared to controls (P = 0.002).

Seventeen cases received heparin on induction during their index procedure, compared to 23 controls (P = 0.24). Additionally, 63 cases began a prophylaxis regimen within 24 hours of surgery end time, compared to 68 controls (P = 0.24). The chemoprophylactic regimens utilized in cases and in controls are summarized in Figure 2. Of note, only 26 cases and 32 controls received standard prophylactic regimens with no missed doses (heparin 5000 units 3 times daily or enoxaparin 40 mg daily). Additionally, in over half of cases and a third of controls, nonstandard regimens were ordered. Examples of nonstandard regimens included nonstandard heparin or enoxaparin doses, low-dose warfarin, or aspirin alone. In most cases, nonstandard regimens were justified on the basis of high risk for bleeding.

Mechanical prophylaxis with pneumatic sequential compression devices (SCDs) was ordered in 93 (91%) cases and 87 (85%) controls; however, we were unable to accurately document uniform compliance in the use of these devices.

With regard to evaluation of our process measures, we found only 17% of cases and controls combined actually had a VTE risk assessment in their chart, and when it was present, it was often incomplete or was completed inaccurately.

Discussion

The goal of this study was to identify factors (patient characteristics and/or processes of care) that may be contributing to the higher than expected incidence of VTE events at our medical center, despite internal audits suggesting near perfect compliance with SCIP-mandated protocols. We found that in addition to usual risk factors for VTE, an overarching theme of our case cohort was their high complexity of illness. At baseline, these patients had significantly greater rates of stroke, thrombophilia, severe lung disease, infection, and history of VTE than controls. Moreover, the hospital courses of cases were significantly more complex than those of controls, as these patients had more procedures, longer lengths of stay and longer index operations, higher rates of postoperative bed rest exceeding 12 hours, and more prevalent central venous access than controls (Table 2). Several of these risk factors have been found to contribute to VTE development despite compliance with prophylaxis protocols.

Cassidy et al reviewed a cohort of nontrauma general surgery patients who developed VTE despite receiving appropriate prophylaxis and found that both multiple operations and emergency procedures contributed to the failure of VTE prophylaxis.¹¹ Similarly, Wang et al identified several independent risk factors for VTE despite thromboprophylaxis, including central venous access and infection, as well as intensive care unit admission, hospitalization for cranial surgery, and admission from a long-term care facility.¹² While our study did not capture some of these additional factors considered by Wang et al, the presence of risk factors not captured in traditional assessment tools suggests that additional consideration for complex patients is warranted.

In addition to these nonmodifiable patient characteristics, aspects of our VTE prophylaxis processes likely contributed to the higher than expected rate of VTE. While the electronic medical record at our institution does contain a VTE risk assessment tool based on the Caprini score, we found it often is not used at all or is used incorrectly/incompletely, which likely reflects the fact that physicians are neither prompted nor required to complete the assessment prior to prescribing VTE prophylaxis.

There is a significant body of evidence demonstrating that mandatory computerized VTE risk assessments can effectively reduce VTE rates and that improved outcomes occur shortly after implementation. Cassidy et al demonstrated the benefits of instituting a hospital-wide, mandatory, Caprini-based computerized VTE risk assessment that provides prophylaxis/early ambulation recommendations. Two years after implementing this system, they observed an 84% reduction in DVTs (P < 0.001) and a 55% reduction in PEs (P < 0.001).¹³ Nimeri et al had similarly impressive success, achieving a reduction in their NSQIP O/E for PE/DVT in general surgery from 6.00 in 2010 to 0.82 (for DVTs) and 0.78 (for PEs) 5 years after implementation of mandatory VTE risk assessment (though they noted that the most dramatic reduction occurred 1 year after implementation).¹⁴ Additionally, a recent systematic review and meta-analysis by Borab et al found computerized VTE risk assessments to be associated with a significant decrease in VTE events.¹⁵

The risk assessment tool used at our institution is qualitative in nature, and current literature suggests that employing a more quantitative tool may yield improved outcomes. Numerous studies have highlighted the importance of identifying patients at very high risk for VTE, as higher risk may necessitate more careful consideration of their prophylactic regimens. Obi et al found patients with Caprini scores higher than 8 to be at significantly greater risk of developing VTE compared to patients with scores of 7 or 8. Also, patients with scores of 7 or 8 were significantly more likely to have a VTE compared to those with scores of 5 or 6.¹⁶ In another study, Lobastov et al identified Caprini scores of 11 or higher as representing an extremely high-risk category for which standard prophylaxis regimens may not be effective.¹⁷ Thus, while having mandatory risk assessment has been shown to dramatically decrease VTE incidence, it is important to consider the magnitude of the numerical risk score. This is of particular importance at medical centers with high case-mix indices where patients at the highest risk might need to be managed with different prophylactic guidelines.

Another notable aspect of the process at our hospital was the great variation in the types of prophylactic regimens ordered, and the adherence to what was ordered. Only 25.5% of patients were maintained on a standard prophylactic regimen with no missed doses (heparin 5000 every 8 hours or enoxaparin 40 mg daily). Thus, the vast majority of the patients who went on to develop VTE either were prescribed a nontraditional prophylaxis regimen or missed doses of standard agents. The need for secondary surgical procedures or other invasive interventions may explain many, but not all, of the missed doses.

The timing of prophylaxis initiation for our patients was also found to deviate from accepted standards. Only 16.8% of cases received prophylaxis upon induction of anesthesia, and furthermore, 38% of cases did not receive any anticoagulation within 24 hours of their index operation. While this variability in prophylaxis implementation was acceptable within the SCIP guidelines based on “high risk for bleeding” or other considerations, it likely contributed to our suboptimal outcomes. The variations and interruptions in prophylactic regimens speak to barriers that have previously been reported as contributing factors to noncompliance with VTE prophylaxis.¹⁸

Given these known barriers and the observed underutilization and improper use of our risk assessment tool, we have recently changed our surgical admission order sets such that a mandatory quantitative risk assessment must be done for every surgical patient at the time of admission/operation before other orders can be completed. Following completion of the assessment, the physician will be presented with an appropriate standard regimen based on the individual patient’s risk assessment. Early results of our VTE quality improvement project have been satisfying: in the most recent NSQIP semi-annual report, our O/E for VTE was 0.74, placing us in the first decile. Some of these early reports may simply be the product of the Hawthorne effect; however, we are encouraged by the early improvements seen in other research. While we are hopeful that these changes will result in sustainable improvements in outcomes, patients at extremely high risk may require novel weight-based or otherwise customized aggressive prophylactic regimens. Such regimens have already been proposed for arthroplasty and other high-risk patients.

Future research may identify other risk factors not captured by traditional risk assessments. In addition, research should continue to explore the use and efficacy of standard prophylactic regimens in these populations to help determine if they are sufficient. Currently, weight-based low-molecular-weight heparin dosing and alternative regimens employing fondaparinux are under investigation for very-high-risk patients.¹⁹

There were several limitations to the present study. First, due to the retrospective design of our study, we could collect only data that had been uniformly recorded in the charts throughout the study period. Second, we were unable to accurately assess compliance with mechanical prophylaxis. While our chart review showed that the vast majority of cases and controls were ordered to have mechanical prophylaxis, it is impossible to document how often these devices were used appropriately in a retrospective analysis. Anecdotal observation suggests that once patients are out of post-anesthesia or critical care units, SCD use is not standardized. The inability to measure compliance precisely may be leading to an overestimation of our compliance with prophylaxis. Finally, because our study included only patients who underwent surgery at our hospital, our observations may not be generalizable outside our institution.

Conclusion

Our study findings reinforce the importance of attention to detail in VTE risk assessment and in ordering and administering VTE prophylactic regimens, especially in high-risk surgical patients. While we adhered to the SCIP-mandated prophylaxis requirements, the complexity of our patients and our lack of a truly standardized approach to risk assessment and prophylactic regimens resulted in suboptimal outcomes. Stricter and more quantitative mandatory VTE risk assessment, along with highly standardized VTE prophylaxis regimens, are required to achieve optimal outcomes.

Corresponding author: Jason C. DeGiovanni, MS, BA, [email protected].

Financial disclosures: None.

Influenza gets a lot of attention each winter, but respiratory syncytial virus (RSV) and other respiratory viruses have as much or more impact on pediatric populations, particularly certain high-risk groups. But currently there are no vaccines for noninfluenza respiratory viruses. That said, several are under development, for RSV and parainfluenza.

Which groups are likely to get the most benefit from these newer vaccines?

We all are aware of the extra vulnerability to respiratory viruses (RSV being the most frequent) in premature infants, those with chronic lung disease, or those with congenital heart syndromes; such vulnerable patients are not infrequently seen in routine practice. But patients from another less frequent category – those with neuromuscular disease – may be even more vulnerable and may benefit more from new vaccines. A recent report shined a brighter light on such a group.

Real-world data from a nationwide Canadian surveillance system (CARESS) was used to analyze relative risks of categories of young children who are thought to be vulnerable to respiratory viruses, with a particular focus on those with neuromuscular disease. The CARESS investigators analyzed 12 years’ data on respiratory hospitalizations from among palivizumab-prophylaxed patients (including specific data on RSV when patients were tested for RSV per standard of care).¹ Unfortunately, RSV testing was not universal despite hospitalization, so the true incidence of RSV-specific hospitalizations was likely underestimated.

Nevertheless, more than 25,000 children from 2005 through 2017 were grouped into three categories of palivizumab-prophylaxed high-risk children: standard indications (SI), n = 20,335; chronic medical conditions (CMD), n = 4,063; and neuromuscular disease (NMD), n = 605. This study is notable for having a relatively large number of neuromuscular disease subjects. Two-thirds of each group were fully palivizumab adherent.

The SI group included the standard American Academy of Pediatrics–recommended groups, such as premature infants, congenital heart disease, etc.

The CMD group included conditions that lead clinicians to use palivizumab off label, such as cystic fibrosis, congenital airway anomalies, immunodeficiency, and pulmonary disorders.

The NMD participants were subdivided into two groups. Group 1 comprised general hypotonic neuromuscular diseases such as hypoxic-ischemic encephalopathy, Prader-Willi syndrome, chromosomal disorders, and migration/demyelinating diseases. Group 2 included more severe infantile neuromuscular disorders, such as spinal muscular atrophy, myotonic dystrophy, centronuclear and nemaline myopathy, mitochondrial and glycogen storage myopathies, or arthrogryposis.

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospital–Kansas City, Mo. Children’s Mercy Hospital receives grant funding to study two candidate RSV vaccines. The hospital also receives CDC funding under the New Vaccine Surveillance Network for multicenter surveillance of acute respiratory infections, including influenza, RSV, and parainfluenza virus. Email Dr. Harrison at [email protected].

References

1. Pediatr Infect Dis J. 2019 Apr 10. doi: 10.1097/INF.0000000000002297.

2. “Advances in RSV Vaccine Research and Development – A Global Agenda.”

3. J Pediatric Infect Dis Soc. 2015 Dec;4(4): e143-6.

4. J Virol. 2015 Oct;89(20):10319-32.

5. Vaccine. 2017 Dec 18;35(51):7139-46.

Influenza gets a lot of attention each winter, but respiratory syncytial virus (RSV) and other respiratory viruses have as much or more impact on pediatric populations, particularly certain high-risk groups. But currently there are no vaccines for noninfluenza respiratory viruses. That said, several are under development, for RSV and parainfluenza.

Which groups are likely to get the most benefit from these newer vaccines?

We all are aware of the extra vulnerability to respiratory viruses (RSV being the most frequent) in premature infants, those with chronic lung disease, or those with congenital heart syndromes; such vulnerable patients are not infrequently seen in routine practice. But patients from another less frequent category – those with neuromuscular disease – may be even more vulnerable and may benefit more from new vaccines. A recent report shined a brighter light on such a group.

Real-world data from a nationwide Canadian surveillance system (CARESS) was used to analyze relative risks of categories of young children who are thought to be vulnerable to respiratory viruses, with a particular focus on those with neuromuscular disease. The CARESS investigators analyzed 12 years’ data on respiratory hospitalizations from among palivizumab-prophylaxed patients (including specific data on RSV when patients were tested for RSV per standard of care).¹ Unfortunately, RSV testing was not universal despite hospitalization, so the true incidence of RSV-specific hospitalizations was likely underestimated.

Nevertheless, more than 25,000 children from 2005 through 2017 were grouped into three categories of palivizumab-prophylaxed high-risk children: standard indications (SI), n = 20,335; chronic medical conditions (CMD), n = 4,063; and neuromuscular disease (NMD), n = 605. This study is notable for having a relatively large number of neuromuscular disease subjects. Two-thirds of each group were fully palivizumab adherent.

The SI group included the standard American Academy of Pediatrics–recommended groups, such as premature infants, congenital heart disease, etc.

The CMD group included conditions that lead clinicians to use palivizumab off label, such as cystic fibrosis, congenital airway anomalies, immunodeficiency, and pulmonary disorders.

The NMD participants were subdivided into two groups. Group 1 comprised general hypotonic neuromuscular diseases such as hypoxic-ischemic encephalopathy, Prader-Willi syndrome, chromosomal disorders, and migration/demyelinating diseases. Group 2 included more severe infantile neuromuscular disorders, such as spinal muscular atrophy, myotonic dystrophy, centronuclear and nemaline myopathy, mitochondrial and glycogen storage myopathies, or arthrogryposis.

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospital–Kansas City, Mo. Children’s Mercy Hospital receives grant funding to study two candidate RSV vaccines. The hospital also receives CDC funding under the New Vaccine Surveillance Network for multicenter surveillance of acute respiratory infections, including influenza, RSV, and parainfluenza virus. Email Dr. Harrison at [email protected].

References

1. Pediatr Infect Dis J. 2019 Apr 10. doi: 10.1097/INF.0000000000002297.

2. “Advances in RSV Vaccine Research and Development – A Global Agenda.”

3. J Pediatric Infect Dis Soc. 2015 Dec;4(4): e143-6.

4. J Virol. 2015 Oct;89(20):10319-32.

5. Vaccine. 2017 Dec 18;35(51):7139-46.

Influenza gets a lot of attention each winter, but respiratory syncytial virus (RSV) and other respiratory viruses have as much or more impact on pediatric populations, particularly certain high-risk groups. But currently there are no vaccines for noninfluenza respiratory viruses. That said, several are under development, for RSV and parainfluenza.

Which groups are likely to get the most benefit from these newer vaccines?

We all are aware of the extra vulnerability to respiratory viruses (RSV being the most frequent) in premature infants, those with chronic lung disease, or those with congenital heart syndromes; such vulnerable patients are not infrequently seen in routine practice. But patients from another less frequent category – those with neuromuscular disease – may be even more vulnerable and may benefit more from new vaccines. A recent report shined a brighter light on such a group.

Real-world data from a nationwide Canadian surveillance system (CARESS) was used to analyze relative risks of categories of young children who are thought to be vulnerable to respiratory viruses, with a particular focus on those with neuromuscular disease. The CARESS investigators analyzed 12 years’ data on respiratory hospitalizations from among palivizumab-prophylaxed patients (including specific data on RSV when patients were tested for RSV per standard of care).¹ Unfortunately, RSV testing was not universal despite hospitalization, so the true incidence of RSV-specific hospitalizations was likely underestimated.

Nevertheless, more than 25,000 children from 2005 through 2017 were grouped into three categories of palivizumab-prophylaxed high-risk children: standard indications (SI), n = 20,335; chronic medical conditions (CMD), n = 4,063; and neuromuscular disease (NMD), n = 605. This study is notable for having a relatively large number of neuromuscular disease subjects. Two-thirds of each group were fully palivizumab adherent.

The SI group included the standard American Academy of Pediatrics–recommended groups, such as premature infants, congenital heart disease, etc.

The CMD group included conditions that lead clinicians to use palivizumab off label, such as cystic fibrosis, congenital airway anomalies, immunodeficiency, and pulmonary disorders.

The NMD participants were subdivided into two groups. Group 1 comprised general hypotonic neuromuscular diseases such as hypoxic-ischemic encephalopathy, Prader-Willi syndrome, chromosomal disorders, and migration/demyelinating diseases. Group 2 included more severe infantile neuromuscular disorders, such as spinal muscular atrophy, myotonic dystrophy, centronuclear and nemaline myopathy, mitochondrial and glycogen storage myopathies, or arthrogryposis.

Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospital–Kansas City, Mo. Children’s Mercy Hospital receives grant funding to study two candidate RSV vaccines. The hospital also receives CDC funding under the New Vaccine Surveillance Network for multicenter surveillance of acute respiratory infections, including influenza, RSV, and parainfluenza virus. Email Dr. Harrison at [email protected].

References

1. Pediatr Infect Dis J. 2019 Apr 10. doi: 10.1097/INF.0000000000002297.

2. “Advances in RSV Vaccine Research and Development – A Global Agenda.”

3. J Pediatric Infect Dis Soc. 2015 Dec;4(4): e143-6.

4. J Virol. 2015 Oct;89(20):10319-32.

5. Vaccine. 2017 Dec 18;35(51):7139-46.

Hematopoietic stem cell transplantation (HSCT) is increasingly being used to treat hematologic malignancies as well as nonmalignant diseases and solid tumors. Over the past 2 decades overall survival following transplant and transplant-related mortality have improved.¹ With this increased survival, there is a need to focus on late complications after transplantation. Pulmonary complications are a common but sometimes underrecognized cause of late morbidity and mortality in HSCT patients. This article, the second of 2 articles on post-HSCT pulmonary complications, reviews late-onset complications, with a focus on the evaluation and treatment of bronchiolitis obliterans syndrome (BOS), one of the most common and serious late pulmonary complications in HSCT patients. The first article reviewed the management of early-onset pulmonary complications and included a basic overview of stem cell transplantation, discussion of factors associated with pulmonary complications, and a review of methods for assessing pretransplant risk for pulmonary complications in patients undergoing HSCT.²

Case Presentation

A 40-year-old white woman with a history of acute myeloid leukemia status post peripheral blood stem cell transplant presents with dyspnea on exertion, which she states started about 1 month ago and now is limiting her with even 1 flight of stairs. She also complains of mild dry cough and a 4- to 5-lb weight loss over the past 1 to 2 months. She has an occasional runny nose, but denies gastroesophageal reflux, fevers, chills, or night sweats. She has a history of matched related sibling donor transplant with busulfan and cyclophosphamide conditioning 1 year prior to presentation. She has had significant graft-versus-host disease (GVHD), affecting the liver, gastrointestinal tract, skin, and eyes.

On physical examination, heart rate is 110 beats/min, respiratory rate is 16 breaths/min, blood pressure is 92/58 mm Hg, and the patient is afebrile. Eye exam reveals scleral injection, mouth shows dry mucous membranes with a few white plaques, and the skin has chronic changes with a rash over both arms. Cardiac exam reveals tachycardia but regular rhythm and there are no murmurs, rubs, or gallops. Lungs are clear bilaterally and abdomen shows no organomegaly.

Laboratory exam shows a white blood cell count of 7800 cells/μL, hemoglobin level of 12.4 g/dL, and platelet count of 186 × 10³/μL. Liver enzymes are mildly elevated. Chest radiograph shows clear lung fields bilaterally.

• What is the differential in this patient with dyspnea 1 year after transplantation?

Late pulmonary complications are generally accepted as those occurring more than 100 days post transplant. This period of time is characterized by chronic GVHD and impaired cellular and humoral immunity. Results of longitudinal studies of infections in adult HSCT patients suggest that special attention should be paid to allogeneic HSCT recipients for post-engraftment infectious pulmonary complications.³ Encapsulated bacteria such as Haemophilus influenzae and Streptococcus pneumoniae are the most frequent bacterial organisms causing late infectious pulmonary complications. Nontuberculous mycobacteria and Nocardia should also be considered. Depending upon geographic location, social and occupational risk factors, and prevalence, tuberculosis should also enter the differential.

There are many noninfectious late-onset pulmonary complications after HSCT. Unfortunately, the literature has divided pulmonary complications after HSCT using a range of criteria and classifications based upon timing, predominant pulmonary function test (PFT) findings, and etiology. These include early versus late, obstructive versus restrictive, and infectious versus noninfectious, which makes a comprehensive literature review of late pulmonary complications difficult. The most common noninfectious late-onset complications are bronchiolitis obliterans, cryptogenic organizing pneumonia (previously referred to as bronchiolitis obliterans organizing pneumonia, or BOOP), and interstitial pneumonia. Other rarely reported complications include eosinophilic pneumonia, pulmonary alveolar proteinosis, air leak syndrome, and pulmonary hypertension.

Case Continued

Because the patient does not have symptoms of infection, PFTs are obtained. Pretransplant PFTs and current PFTs are shown in Table 1.

• What is the diagnosis in this case?

Bronchiolitis Obliterans

BOS is one of the most common and most serious late-onset pulmonary diseases after allogeneic transplantation. It is considered the pulmonary form of chronic GVHD. BOS was first described in 1982 in patients with chronic GVHD after bone marrow transplantation.⁴ Many differing definitions of bronchiolitis obliterans have been described in the literature. A recent review of the topic cites 10 different published sets of criteria for the diagnosis of bronchiolitis obliterans.⁵ Traditionally, bronchiolitis obliterans was thought to occur in 2% to 8% of patients undergoing allogeneic HSCT, but these findings were from older studies that used a diagnosis based on very specific pathology findings. When more liberal diagnostic criteria are used, the incidence may be as high as 26% of allogeneic HSCT patients.⁶

Bronchiolitis obliterans is a progressive lung disease characterized by narrowing of the terminal airways and obliteration of the terminal bronchi. Pathology may show constrictive bronchiolitis but can also show lymphocytic bronchiolitis, which may be associated with a better outcome.⁷ As noted, bronchiolitis obliterans has traditionally been considered a pathologic diagnosis. Current diagnostic criteria have evolved based upon the difficulty in obtaining this diagnosis through transbronchial biopsy given the patchy nature of the disease.⁸ The gold standard of open lung biopsy is seldom pursued in the post-HSCT population as the procedure continues to carry a worrisome risk-benefit profile.

The 2005 National Institutes of Health (NIH) consensus development project on criteria for clinical trials in chronic GVHD developed a clinical strategy for diagnosing BOS using the following criteria: absence of active infection, decreased forced expiratory volume in 1 second (FEV₁) < 75%, FEV₁/forced vital capacity (FVC) ratio of < 70%, and evidence of air trapping on high-resolution computed tomography (HRCT) or PFTs (residual volume > 120%). These diagnostic criteria were applied to a small series of patients with clinically identified bronchiolitis obliterans or biopsy-proven bronchiolitis obliterans. Only 18% of these patients met the requirements for the NIH consensus definition.⁵ A 2011 study that applied the NIH criteria found an overall prevalence of 5.5% among all transplant recipients but a prevalence of 14% in patients with GVHD.⁹ In 2014, the NIH consensus development group updated their recommendations. The new criteria for diagnosis of BOS require the presence of  airflow obstruction (FEV₁/FVC < 70% or 5^th percentile of predicted), FEV₁ < 75% predicted with a ≥ 10% decline in fewer than 2 years, absence of infection, and presence of air trapping (by expiratory computed tomography [CT] scan or PFT with residual volume >120% predicted) (Table 2).

Some issues must be considered when determining airflow obstruction. The 2005 NIH working group recommends using Crapo as the reference set,¹¹ but the National Health and Nutrition Examination Survey (NHANES) III reference values are the preferred reference set at this time¹² and should be used in the United States. A recent article showed that the NHANES values were superior to older reference sets (however, they did not use Crapo as the comparison), although this study used the lower limit of normal as compared with the fixed 70% ratio.¹³ The 2014 NIH consensus group does not recommend a specific reference set and recognizes an FEV₁/FVC ratio of 70% or less than the lower limit of normal as the cutoff value for airflow obstruction.¹⁰

Another issue in PFT interpretation is the finding of a decrease in FEV1 and FVC and normal total lung capacity, which is termed a nonspecific pattern. This pattern has been reported to occur in 9% of all PFTs and usually is associated with obstructive lung disease or obesity.¹⁴ A 2013 study described the nonspecific pattern as a BOS subgroup occurring in up to 31% of bronchiolitis obliterans patients.¹⁵

• What are the radiographic findings of BOS?

Chest radiograph is often normal in BOS. As discussed, air trapping can be documented using HRCT, according to the NIH clinical definition of bronchiolitis obliterans.¹⁶ A study that explored findings and trends seen on HRCT in HSCT patients with BOS found that the syndrome in these patients is characterized by central airway dilatation.¹⁷ Expiratory airway trapping on HRCT is the main finding, and this is best demonstrated on HRCT during inspiratory and expiratory phases.¹⁸ Other findings are bronchial wall thickening, parenchymal hypoattenuation, bronchiectasis, and centrilobular nodules.¹⁹

Galbán and colleagues developed a new technique called parametric response mapping that uses CT scanners to quantify normal parenchyma, functional small airway disease, emphysema, and parenchymal disease as relative lung volumes.²⁰ This technique can detect airflow obstruction and small airway disease and was found to be a good method for detecting BOS after HSCT. In their study of parametric response mapping, the authors found that functional small airway disease affecting 28% or more of the total lung was highly indicative of bronchiolitis obliterans.²⁰

• What therapies are used to treat BOS?

Traditionally, BOS has been treated with systemic immunosuppression. The recommended treatment had been systemic steroids at approximately 1 mg/ kg. However, it is increasingly recognized that BOS responds poorly to systemic steroids, and systemic steroids may actually be harmful and associated with increased mortality.^15,21 The chronic GVHD recommendations from 2005 recommend ancillary therapy with inhaled corticosteroids and pulmonary rehabilitation.¹¹ The updated 2011 German consensus statement lays out a clear management strategy for mild and moderate-severe disease with monitoring recommendations.²² The 2014 NIH chronic GVHD working group recommends fluticasone, azithromycin, and montelukast (ie, the FAM protocol) for treating BOS.²³ FAM therapy in BOS may help lower the systemic steroid dose.^24,25 Montelukast is not considered a treatment mainstay for BOS after lung transplant, but there is a study showing possible benefit in chronic GVHD.²⁶ An evaluation of the natural history of a cohort of BOS patients treated with FAM therapy showed a rapid decline of FEV₁ in the 6 months prior to diagnosis and treatment of BOS and subsequent stabilization following diagnosis and treatment.²⁷ The benefit of high-dose inhaled corticosteroids or the combination of inhaled corticosteroids and long-acting beta-agonists has been demonstrated in small studies, which showed that these agents stabilized FEV₁ and avoided the untoward side effects of systemic corticosteroids.^28–30

Macrolide antibiotics have been explored as a treatment for BOS post HSCT because pilot studies suggested that azithromycin improved or stabilized FEV₁ in patients with BOS after lung transplant or HSCT.^31–33 Other studies of azithromycin have not shown benefit in the HSCT population after 3 months of therapy.³⁴ A recent meta-analysis could neither support or refute the benefit of azithromycin for BOS after HSCT.³⁵ In the lung transplant population, a study showed that patients who were started on azithromycin after transplant and continued on it 3 times a week had improved FEV₁; these patients also had a reduced rate of BOS and improved overall and BOS-free survival 2 years after transplant.³⁶ However, these benefits of azithromycin have not been observed in patients after HSCT. In fact, the ALLOZITHRO trial was stopped early because prophylactic azithromycin started at the time of the conditioning regimen with HSCT was associated with increased hematologic disease relapse, a decrease in airflow-decline-free survival, and reduced 2-year survival.³⁰

Azithromycin is believed to exert an effect by its anti-inflammatory properties and perhaps by decreasing lung neutrophilia (it may be most beneficial in the subset of patients with high neutrophilia on bronchoalveolar lavage [BAL]).³⁰ Adverse effects of chronic azithromycin include QT prolongation, cardiac arrhythmia, hearing loss, and antibiotic-resistant organism colonization.^37,38

Other therapies include pulmonary rehabilitation, which may improve health-related quality of life and 6-minute walk distance,³⁹ extracorporeal photopheresis,⁴⁰ immunosuppression with calcineurin inhibitors or mycophenolate mofetil,^21,41 and lung transplantation.^42–44 A study with imatinib for the treatment of lung disease in steroid-refractory GVHD has shown promising results, but further validation with larger clinical trials is required.⁴⁵

Case Continued

The patient is diagnosed with BOS and is treated for several months with prednisone 40 mg/day weaned over 3 months. She is started on inhaled corticosteroids, a proton pump inhibitor, and azithromycin 3 times per week, but she has a progressive decline in FEV₁.  She starts pulmonary rehabilitation but continues to functionally decline. Over the next year she develops bilateral pneumothoraces and bilateral cavitary nodules (Figure 1).

• What is causing this decline and the radiographic abnormalities?

Spontaneous air leak syndrome has been described in a little more than 1% of patients undergoing HSCT and has included pneumothorax and mediastinal and subcutaneous emphysema.⁴⁶ It appears that air leak syndrome is more likely to occur in patients with chronic GVHD.⁴⁷ The association between chronic GVHD and air leak syndrome could explain this patient’s recurrent pneumothoraces. The recurrent cavitary nodules are suspicious for infectious etiologies such as nontuberculous mycobacteria, tuberculosis, and fungal infections.

Case Continued

During an episode of pneumothorax, the patient undergoes chest tube placement, pleurodesis, and lung biopsy.  Pathology reveals bronchiolitis obliterans as well as organizing pneumonia (Figure 2). No organisms are seen on acid-fast bacilli or GMS stains.

• What are the other late-onset noninfectious pulmonary complications?

Definitions of other late noninfectious pulmonary complications following HSCT are shown in Table 3.

Interstitial pneumonias may represent COP or may be idiopathic pneumonia syndrome with a later onset or a nonspecific interstitial pneumonia. This syndrome is poorly defined, with a number of differing definitions of the syndrome published in the literature.^50–55

A rare pulmonary complication after HSCT is pulmonary veno-occlusive disease (PVOD). Pulmonary hypertension has been reported after HSCT,⁵⁶ but PVOD is a subset of pulmonary hypertension. It is associated with pleural effusions and volume overload on chest radiography.^57,58 It may present early or late after transplant and is poorly understood.

Besides obstructive and restrictive PFT abnormalities, changes in small airway function⁵⁹ after transplant and loss in diffusing capacity of the lungs for carbon monoxide (Dlco) in the first 5 years after transplant have been reported, although these parameters improve by 10 years after transplant.⁶⁰ There do not appear to be any changes in responsiveness to methacholine.⁶¹ Losses in respiratory muscle strength (PiMax and PeMax after transplant) have been reported.⁶² Lower aerobic exercise capacity (Vo₂max) after pediatric HSCT has also been reported.⁶³

Case Conclusion

The patient’s lung function continues to worsen, but no infectious etiologies are discovered. Ultimately, she dies of respiratory failure caused by progressive bronchiolitis obliterans.

Conclusion

Late pulmonary complications occur frequently in patients who have undergone HSCT. These complications can be classified as infectious versus noninfectious etiologies. Late-onset complications are more common in allogeneic transplantations because they are associated with chronic GVHD. These complications can be manifestations of pulmonary GHVD or can be infectious complications associated with prolonged immunosuppression. Appropriate monitoring for the development of BOS is essential. Early and aggressive treatment of respiratory infections and diagnostic bronchoscopy with BAL can help elucidate most infectious causes. Still, diagnostic challenges remain and multiple causes of respiratory deterioration can be present concurrently in the post-HSCT patient. Steroid therapy remains the mainstay treatment for most noninfectious pulmonary complications and should be strongly considered once infection is effectively ruled out.

Hematopoietic stem cell transplantation (HSCT) is increasingly being used to treat hematologic malignancies as well as nonmalignant diseases and solid tumors. Over the past 2 decades overall survival following transplant and transplant-related mortality have improved.¹ With this increased survival, there is a need to focus on late complications after transplantation. Pulmonary complications are a common but sometimes underrecognized cause of late morbidity and mortality in HSCT patients. This article, the second of 2 articles on post-HSCT pulmonary complications, reviews late-onset complications, with a focus on the evaluation and treatment of bronchiolitis obliterans syndrome (BOS), one of the most common and serious late pulmonary complications in HSCT patients. The first article reviewed the management of early-onset pulmonary complications and included a basic overview of stem cell transplantation, discussion of factors associated with pulmonary complications, and a review of methods for assessing pretransplant risk for pulmonary complications in patients undergoing HSCT.²

Case Presentation

A 40-year-old white woman with a history of acute myeloid leukemia status post peripheral blood stem cell transplant presents with dyspnea on exertion, which she states started about 1 month ago and now is limiting her with even 1 flight of stairs. She also complains of mild dry cough and a 4- to 5-lb weight loss over the past 1 to 2 months. She has an occasional runny nose, but denies gastroesophageal reflux, fevers, chills, or night sweats. She has a history of matched related sibling donor transplant with busulfan and cyclophosphamide conditioning 1 year prior to presentation. She has had significant graft-versus-host disease (GVHD), affecting the liver, gastrointestinal tract, skin, and eyes.

On physical examination, heart rate is 110 beats/min, respiratory rate is 16 breaths/min, blood pressure is 92/58 mm Hg, and the patient is afebrile. Eye exam reveals scleral injection, mouth shows dry mucous membranes with a few white plaques, and the skin has chronic changes with a rash over both arms. Cardiac exam reveals tachycardia but regular rhythm and there are no murmurs, rubs, or gallops. Lungs are clear bilaterally and abdomen shows no organomegaly.

Laboratory exam shows a white blood cell count of 7800 cells/μL, hemoglobin level of 12.4 g/dL, and platelet count of 186 × 10³/μL. Liver enzymes are mildly elevated. Chest radiograph shows clear lung fields bilaterally.

• What is the differential in this patient with dyspnea 1 year after transplantation?

Late pulmonary complications are generally accepted as those occurring more than 100 days post transplant. This period of time is characterized by chronic GVHD and impaired cellular and humoral immunity. Results of longitudinal studies of infections in adult HSCT patients suggest that special attention should be paid to allogeneic HSCT recipients for post-engraftment infectious pulmonary complications.³ Encapsulated bacteria such as Haemophilus influenzae and Streptococcus pneumoniae are the most frequent bacterial organisms causing late infectious pulmonary complications. Nontuberculous mycobacteria and Nocardia should also be considered. Depending upon geographic location, social and occupational risk factors, and prevalence, tuberculosis should also enter the differential.

There are many noninfectious late-onset pulmonary complications after HSCT. Unfortunately, the literature has divided pulmonary complications after HSCT using a range of criteria and classifications based upon timing, predominant pulmonary function test (PFT) findings, and etiology. These include early versus late, obstructive versus restrictive, and infectious versus noninfectious, which makes a comprehensive literature review of late pulmonary complications difficult. The most common noninfectious late-onset complications are bronchiolitis obliterans, cryptogenic organizing pneumonia (previously referred to as bronchiolitis obliterans organizing pneumonia, or BOOP), and interstitial pneumonia. Other rarely reported complications include eosinophilic pneumonia, pulmonary alveolar proteinosis, air leak syndrome, and pulmonary hypertension.

Case Continued

Because the patient does not have symptoms of infection, PFTs are obtained. Pretransplant PFTs and current PFTs are shown in Table 1.

• What is the diagnosis in this case?

Bronchiolitis Obliterans

BOS is one of the most common and most serious late-onset pulmonary diseases after allogeneic transplantation. It is considered the pulmonary form of chronic GVHD. BOS was first described in 1982 in patients with chronic GVHD after bone marrow transplantation.⁴ Many differing definitions of bronchiolitis obliterans have been described in the literature. A recent review of the topic cites 10 different published sets of criteria for the diagnosis of bronchiolitis obliterans.⁵ Traditionally, bronchiolitis obliterans was thought to occur in 2% to 8% of patients undergoing allogeneic HSCT, but these findings were from older studies that used a diagnosis based on very specific pathology findings. When more liberal diagnostic criteria are used, the incidence may be as high as 26% of allogeneic HSCT patients.⁶

Bronchiolitis obliterans is a progressive lung disease characterized by narrowing of the terminal airways and obliteration of the terminal bronchi. Pathology may show constrictive bronchiolitis but can also show lymphocytic bronchiolitis, which may be associated with a better outcome.⁷ As noted, bronchiolitis obliterans has traditionally been considered a pathologic diagnosis. Current diagnostic criteria have evolved based upon the difficulty in obtaining this diagnosis through transbronchial biopsy given the patchy nature of the disease.⁸ The gold standard of open lung biopsy is seldom pursued in the post-HSCT population as the procedure continues to carry a worrisome risk-benefit profile.

The 2005 National Institutes of Health (NIH) consensus development project on criteria for clinical trials in chronic GVHD developed a clinical strategy for diagnosing BOS using the following criteria: absence of active infection, decreased forced expiratory volume in 1 second (FEV₁) < 75%, FEV₁/forced vital capacity (FVC) ratio of < 70%, and evidence of air trapping on high-resolution computed tomography (HRCT) or PFTs (residual volume > 120%). These diagnostic criteria were applied to a small series of patients with clinically identified bronchiolitis obliterans or biopsy-proven bronchiolitis obliterans. Only 18% of these patients met the requirements for the NIH consensus definition.⁵ A 2011 study that applied the NIH criteria found an overall prevalence of 5.5% among all transplant recipients but a prevalence of 14% in patients with GVHD.⁹ In 2014, the NIH consensus development group updated their recommendations. The new criteria for diagnosis of BOS require the presence of  airflow obstruction (FEV₁/FVC < 70% or 5^th percentile of predicted), FEV₁ < 75% predicted with a ≥ 10% decline in fewer than 2 years, absence of infection, and presence of air trapping (by expiratory computed tomography [CT] scan or PFT with residual volume >120% predicted) (Table 2).

Some issues must be considered when determining airflow obstruction. The 2005 NIH working group recommends using Crapo as the reference set,¹¹ but the National Health and Nutrition Examination Survey (NHANES) III reference values are the preferred reference set at this time¹² and should be used in the United States. A recent article showed that the NHANES values were superior to older reference sets (however, they did not use Crapo as the comparison), although this study used the lower limit of normal as compared with the fixed 70% ratio.¹³ The 2014 NIH consensus group does not recommend a specific reference set and recognizes an FEV₁/FVC ratio of 70% or less than the lower limit of normal as the cutoff value for airflow obstruction.¹⁰

Another issue in PFT interpretation is the finding of a decrease in FEV1 and FVC and normal total lung capacity, which is termed a nonspecific pattern. This pattern has been reported to occur in 9% of all PFTs and usually is associated with obstructive lung disease or obesity.¹⁴ A 2013 study described the nonspecific pattern as a BOS subgroup occurring in up to 31% of bronchiolitis obliterans patients.¹⁵

• What are the radiographic findings of BOS?

Chest radiograph is often normal in BOS. As discussed, air trapping can be documented using HRCT, according to the NIH clinical definition of bronchiolitis obliterans.¹⁶ A study that explored findings and trends seen on HRCT in HSCT patients with BOS found that the syndrome in these patients is characterized by central airway dilatation.¹⁷ Expiratory airway trapping on HRCT is the main finding, and this is best demonstrated on HRCT during inspiratory and expiratory phases.¹⁸ Other findings are bronchial wall thickening, parenchymal hypoattenuation, bronchiectasis, and centrilobular nodules.¹⁹

Galbán and colleagues developed a new technique called parametric response mapping that uses CT scanners to quantify normal parenchyma, functional small airway disease, emphysema, and parenchymal disease as relative lung volumes.²⁰ This technique can detect airflow obstruction and small airway disease and was found to be a good method for detecting BOS after HSCT. In their study of parametric response mapping, the authors found that functional small airway disease affecting 28% or more of the total lung was highly indicative of bronchiolitis obliterans.²⁰

• What therapies are used to treat BOS?

Traditionally, BOS has been treated with systemic immunosuppression. The recommended treatment had been systemic steroids at approximately 1 mg/ kg. However, it is increasingly recognized that BOS responds poorly to systemic steroids, and systemic steroids may actually be harmful and associated with increased mortality.^15,21 The chronic GVHD recommendations from 2005 recommend ancillary therapy with inhaled corticosteroids and pulmonary rehabilitation.¹¹ The updated 2011 German consensus statement lays out a clear management strategy for mild and moderate-severe disease with monitoring recommendations.²² The 2014 NIH chronic GVHD working group recommends fluticasone, azithromycin, and montelukast (ie, the FAM protocol) for treating BOS.²³ FAM therapy in BOS may help lower the systemic steroid dose.^24,25 Montelukast is not considered a treatment mainstay for BOS after lung transplant, but there is a study showing possible benefit in chronic GVHD.²⁶ An evaluation of the natural history of a cohort of BOS patients treated with FAM therapy showed a rapid decline of FEV₁ in the 6 months prior to diagnosis and treatment of BOS and subsequent stabilization following diagnosis and treatment.²⁷ The benefit of high-dose inhaled corticosteroids or the combination of inhaled corticosteroids and long-acting beta-agonists has been demonstrated in small studies, which showed that these agents stabilized FEV₁ and avoided the untoward side effects of systemic corticosteroids.^28–30

Macrolide antibiotics have been explored as a treatment for BOS post HSCT because pilot studies suggested that azithromycin improved or stabilized FEV₁ in patients with BOS after lung transplant or HSCT.^31–33 Other studies of azithromycin have not shown benefit in the HSCT population after 3 months of therapy.³⁴ A recent meta-analysis could neither support or refute the benefit of azithromycin for BOS after HSCT.³⁵ In the lung transplant population, a study showed that patients who were started on azithromycin after transplant and continued on it 3 times a week had improved FEV₁; these patients also had a reduced rate of BOS and improved overall and BOS-free survival 2 years after transplant.³⁶ However, these benefits of azithromycin have not been observed in patients after HSCT. In fact, the ALLOZITHRO trial was stopped early because prophylactic azithromycin started at the time of the conditioning regimen with HSCT was associated with increased hematologic disease relapse, a decrease in airflow-decline-free survival, and reduced 2-year survival.³⁰

Azithromycin is believed to exert an effect by its anti-inflammatory properties and perhaps by decreasing lung neutrophilia (it may be most beneficial in the subset of patients with high neutrophilia on bronchoalveolar lavage [BAL]).³⁰ Adverse effects of chronic azithromycin include QT prolongation, cardiac arrhythmia, hearing loss, and antibiotic-resistant organism colonization.^37,38

Other therapies include pulmonary rehabilitation, which may improve health-related quality of life and 6-minute walk distance,³⁹ extracorporeal photopheresis,⁴⁰ immunosuppression with calcineurin inhibitors or mycophenolate mofetil,^21,41 and lung transplantation.^42–44 A study with imatinib for the treatment of lung disease in steroid-refractory GVHD has shown promising results, but further validation with larger clinical trials is required.⁴⁵

Case Continued

The patient is diagnosed with BOS and is treated for several months with prednisone 40 mg/day weaned over 3 months. She is started on inhaled corticosteroids, a proton pump inhibitor, and azithromycin 3 times per week, but she has a progressive decline in FEV₁.  She starts pulmonary rehabilitation but continues to functionally decline. Over the next year she develops bilateral pneumothoraces and bilateral cavitary nodules (Figure 1).

• What is causing this decline and the radiographic abnormalities?

Spontaneous air leak syndrome has been described in a little more than 1% of patients undergoing HSCT and has included pneumothorax and mediastinal and subcutaneous emphysema.⁴⁶ It appears that air leak syndrome is more likely to occur in patients with chronic GVHD.⁴⁷ The association between chronic GVHD and air leak syndrome could explain this patient’s recurrent pneumothoraces. The recurrent cavitary nodules are suspicious for infectious etiologies such as nontuberculous mycobacteria, tuberculosis, and fungal infections.

Case Continued

During an episode of pneumothorax, the patient undergoes chest tube placement, pleurodesis, and lung biopsy.  Pathology reveals bronchiolitis obliterans as well as organizing pneumonia (Figure 2). No organisms are seen on acid-fast bacilli or GMS stains.

• What are the other late-onset noninfectious pulmonary complications?

Definitions of other late noninfectious pulmonary complications following HSCT are shown in Table 3.

Interstitial pneumonias may represent COP or may be idiopathic pneumonia syndrome with a later onset or a nonspecific interstitial pneumonia. This syndrome is poorly defined, with a number of differing definitions of the syndrome published in the literature.^50–55

A rare pulmonary complication after HSCT is pulmonary veno-occlusive disease (PVOD). Pulmonary hypertension has been reported after HSCT,⁵⁶ but PVOD is a subset of pulmonary hypertension. It is associated with pleural effusions and volume overload on chest radiography.^57,58 It may present early or late after transplant and is poorly understood.

Besides obstructive and restrictive PFT abnormalities, changes in small airway function⁵⁹ after transplant and loss in diffusing capacity of the lungs for carbon monoxide (Dlco) in the first 5 years after transplant have been reported, although these parameters improve by 10 years after transplant.⁶⁰ There do not appear to be any changes in responsiveness to methacholine.⁶¹ Losses in respiratory muscle strength (PiMax and PeMax after transplant) have been reported.⁶² Lower aerobic exercise capacity (Vo₂max) after pediatric HSCT has also been reported.⁶³

Case Conclusion

The patient’s lung function continues to worsen, but no infectious etiologies are discovered. Ultimately, she dies of respiratory failure caused by progressive bronchiolitis obliterans.

Conclusion

Late pulmonary complications occur frequently in patients who have undergone HSCT. These complications can be classified as infectious versus noninfectious etiologies. Late-onset complications are more common in allogeneic transplantations because they are associated with chronic GVHD. These complications can be manifestations of pulmonary GHVD or can be infectious complications associated with prolonged immunosuppression. Appropriate monitoring for the development of BOS is essential. Early and aggressive treatment of respiratory infections and diagnostic bronchoscopy with BAL can help elucidate most infectious causes. Still, diagnostic challenges remain and multiple causes of respiratory deterioration can be present concurrently in the post-HSCT patient. Steroid therapy remains the mainstay treatment for most noninfectious pulmonary complications and should be strongly considered once infection is effectively ruled out.

Hematopoietic stem cell transplantation (HSCT) is increasingly being used to treat hematologic malignancies as well as nonmalignant diseases and solid tumors. Over the past 2 decades overall survival following transplant and transplant-related mortality have improved.¹ With this increased survival, there is a need to focus on late complications after transplantation. Pulmonary complications are a common but sometimes underrecognized cause of late morbidity and mortality in HSCT patients. This article, the second of 2 articles on post-HSCT pulmonary complications, reviews late-onset complications, with a focus on the evaluation and treatment of bronchiolitis obliterans syndrome (BOS), one of the most common and serious late pulmonary complications in HSCT patients. The first article reviewed the management of early-onset pulmonary complications and included a basic overview of stem cell transplantation, discussion of factors associated with pulmonary complications, and a review of methods for assessing pretransplant risk for pulmonary complications in patients undergoing HSCT.²

Case Presentation

A 40-year-old white woman with a history of acute myeloid leukemia status post peripheral blood stem cell transplant presents with dyspnea on exertion, which she states started about 1 month ago and now is limiting her with even 1 flight of stairs. She also complains of mild dry cough and a 4- to 5-lb weight loss over the past 1 to 2 months. She has an occasional runny nose, but denies gastroesophageal reflux, fevers, chills, or night sweats. She has a history of matched related sibling donor transplant with busulfan and cyclophosphamide conditioning 1 year prior to presentation. She has had significant graft-versus-host disease (GVHD), affecting the liver, gastrointestinal tract, skin, and eyes.

On physical examination, heart rate is 110 beats/min, respiratory rate is 16 breaths/min, blood pressure is 92/58 mm Hg, and the patient is afebrile. Eye exam reveals scleral injection, mouth shows dry mucous membranes with a few white plaques, and the skin has chronic changes with a rash over both arms. Cardiac exam reveals tachycardia but regular rhythm and there are no murmurs, rubs, or gallops. Lungs are clear bilaterally and abdomen shows no organomegaly.

Laboratory exam shows a white blood cell count of 7800 cells/μL, hemoglobin level of 12.4 g/dL, and platelet count of 186 × 10³/μL. Liver enzymes are mildly elevated. Chest radiograph shows clear lung fields bilaterally.

• What is the differential in this patient with dyspnea 1 year after transplantation?

Late pulmonary complications are generally accepted as those occurring more than 100 days post transplant. This period of time is characterized by chronic GVHD and impaired cellular and humoral immunity. Results of longitudinal studies of infections in adult HSCT patients suggest that special attention should be paid to allogeneic HSCT recipients for post-engraftment infectious pulmonary complications.³ Encapsulated bacteria such as Haemophilus influenzae and Streptococcus pneumoniae are the most frequent bacterial organisms causing late infectious pulmonary complications. Nontuberculous mycobacteria and Nocardia should also be considered. Depending upon geographic location, social and occupational risk factors, and prevalence, tuberculosis should also enter the differential.

There are many noninfectious late-onset pulmonary complications after HSCT. Unfortunately, the literature has divided pulmonary complications after HSCT using a range of criteria and classifications based upon timing, predominant pulmonary function test (PFT) findings, and etiology. These include early versus late, obstructive versus restrictive, and infectious versus noninfectious, which makes a comprehensive literature review of late pulmonary complications difficult. The most common noninfectious late-onset complications are bronchiolitis obliterans, cryptogenic organizing pneumonia (previously referred to as bronchiolitis obliterans organizing pneumonia, or BOOP), and interstitial pneumonia. Other rarely reported complications include eosinophilic pneumonia, pulmonary alveolar proteinosis, air leak syndrome, and pulmonary hypertension.

Case Continued

Because the patient does not have symptoms of infection, PFTs are obtained. Pretransplant PFTs and current PFTs are shown in Table 1.

• What is the diagnosis in this case?

Bronchiolitis Obliterans

BOS is one of the most common and most serious late-onset pulmonary diseases after allogeneic transplantation. It is considered the pulmonary form of chronic GVHD. BOS was first described in 1982 in patients with chronic GVHD after bone marrow transplantation.⁴ Many differing definitions of bronchiolitis obliterans have been described in the literature. A recent review of the topic cites 10 different published sets of criteria for the diagnosis of bronchiolitis obliterans.⁵ Traditionally, bronchiolitis obliterans was thought to occur in 2% to 8% of patients undergoing allogeneic HSCT, but these findings were from older studies that used a diagnosis based on very specific pathology findings. When more liberal diagnostic criteria are used, the incidence may be as high as 26% of allogeneic HSCT patients.⁶

Bronchiolitis obliterans is a progressive lung disease characterized by narrowing of the terminal airways and obliteration of the terminal bronchi. Pathology may show constrictive bronchiolitis but can also show lymphocytic bronchiolitis, which may be associated with a better outcome.⁷ As noted, bronchiolitis obliterans has traditionally been considered a pathologic diagnosis. Current diagnostic criteria have evolved based upon the difficulty in obtaining this diagnosis through transbronchial biopsy given the patchy nature of the disease.⁸ The gold standard of open lung biopsy is seldom pursued in the post-HSCT population as the procedure continues to carry a worrisome risk-benefit profile.

The 2005 National Institutes of Health (NIH) consensus development project on criteria for clinical trials in chronic GVHD developed a clinical strategy for diagnosing BOS using the following criteria: absence of active infection, decreased forced expiratory volume in 1 second (FEV₁) < 75%, FEV₁/forced vital capacity (FVC) ratio of < 70%, and evidence of air trapping on high-resolution computed tomography (HRCT) or PFTs (residual volume > 120%). These diagnostic criteria were applied to a small series of patients with clinically identified bronchiolitis obliterans or biopsy-proven bronchiolitis obliterans. Only 18% of these patients met the requirements for the NIH consensus definition.⁵ A 2011 study that applied the NIH criteria found an overall prevalence of 5.5% among all transplant recipients but a prevalence of 14% in patients with GVHD.⁹ In 2014, the NIH consensus development group updated their recommendations. The new criteria for diagnosis of BOS require the presence of  airflow obstruction (FEV₁/FVC < 70% or 5^th percentile of predicted), FEV₁ < 75% predicted with a ≥ 10% decline in fewer than 2 years, absence of infection, and presence of air trapping (by expiratory computed tomography [CT] scan or PFT with residual volume >120% predicted) (Table 2).

Some issues must be considered when determining airflow obstruction. The 2005 NIH working group recommends using Crapo as the reference set,¹¹ but the National Health and Nutrition Examination Survey (NHANES) III reference values are the preferred reference set at this time¹² and should be used in the United States. A recent article showed that the NHANES values were superior to older reference sets (however, they did not use Crapo as the comparison), although this study used the lower limit of normal as compared with the fixed 70% ratio.¹³ The 2014 NIH consensus group does not recommend a specific reference set and recognizes an FEV₁/FVC ratio of 70% or less than the lower limit of normal as the cutoff value for airflow obstruction.¹⁰

Another issue in PFT interpretation is the finding of a decrease in FEV1 and FVC and normal total lung capacity, which is termed a nonspecific pattern. This pattern has been reported to occur in 9% of all PFTs and usually is associated with obstructive lung disease or obesity.¹⁴ A 2013 study described the nonspecific pattern as a BOS subgroup occurring in up to 31% of bronchiolitis obliterans patients.¹⁵

• What are the radiographic findings of BOS?

Chest radiograph is often normal in BOS. As discussed, air trapping can be documented using HRCT, according to the NIH clinical definition of bronchiolitis obliterans.¹⁶ A study that explored findings and trends seen on HRCT in HSCT patients with BOS found that the syndrome in these patients is characterized by central airway dilatation.¹⁷ Expiratory airway trapping on HRCT is the main finding, and this is best demonstrated on HRCT during inspiratory and expiratory phases.¹⁸ Other findings are bronchial wall thickening, parenchymal hypoattenuation, bronchiectasis, and centrilobular nodules.¹⁹

Galbán and colleagues developed a new technique called parametric response mapping that uses CT scanners to quantify normal parenchyma, functional small airway disease, emphysema, and parenchymal disease as relative lung volumes.²⁰ This technique can detect airflow obstruction and small airway disease and was found to be a good method for detecting BOS after HSCT. In their study of parametric response mapping, the authors found that functional small airway disease affecting 28% or more of the total lung was highly indicative of bronchiolitis obliterans.²⁰

• What therapies are used to treat BOS?

Traditionally, BOS has been treated with systemic immunosuppression. The recommended treatment had been systemic steroids at approximately 1 mg/ kg. However, it is increasingly recognized that BOS responds poorly to systemic steroids, and systemic steroids may actually be harmful and associated with increased mortality.^15,21 The chronic GVHD recommendations from 2005 recommend ancillary therapy with inhaled corticosteroids and pulmonary rehabilitation.¹¹ The updated 2011 German consensus statement lays out a clear management strategy for mild and moderate-severe disease with monitoring recommendations.²² The 2014 NIH chronic GVHD working group recommends fluticasone, azithromycin, and montelukast (ie, the FAM protocol) for treating BOS.²³ FAM therapy in BOS may help lower the systemic steroid dose.^24,25 Montelukast is not considered a treatment mainstay for BOS after lung transplant, but there is a study showing possible benefit in chronic GVHD.²⁶ An evaluation of the natural history of a cohort of BOS patients treated with FAM therapy showed a rapid decline of FEV₁ in the 6 months prior to diagnosis and treatment of BOS and subsequent stabilization following diagnosis and treatment.²⁷ The benefit of high-dose inhaled corticosteroids or the combination of inhaled corticosteroids and long-acting beta-agonists has been demonstrated in small studies, which showed that these agents stabilized FEV₁ and avoided the untoward side effects of systemic corticosteroids.^28–30

Macrolide antibiotics have been explored as a treatment for BOS post HSCT because pilot studies suggested that azithromycin improved or stabilized FEV₁ in patients with BOS after lung transplant or HSCT.^31–33 Other studies of azithromycin have not shown benefit in the HSCT population after 3 months of therapy.³⁴ A recent meta-analysis could neither support or refute the benefit of azithromycin for BOS after HSCT.³⁵ In the lung transplant population, a study showed that patients who were started on azithromycin after transplant and continued on it 3 times a week had improved FEV₁; these patients also had a reduced rate of BOS and improved overall and BOS-free survival 2 years after transplant.³⁶ However, these benefits of azithromycin have not been observed in patients after HSCT. In fact, the ALLOZITHRO trial was stopped early because prophylactic azithromycin started at the time of the conditioning regimen with HSCT was associated with increased hematologic disease relapse, a decrease in airflow-decline-free survival, and reduced 2-year survival.³⁰

Azithromycin is believed to exert an effect by its anti-inflammatory properties and perhaps by decreasing lung neutrophilia (it may be most beneficial in the subset of patients with high neutrophilia on bronchoalveolar lavage [BAL]).³⁰ Adverse effects of chronic azithromycin include QT prolongation, cardiac arrhythmia, hearing loss, and antibiotic-resistant organism colonization.^37,38

Other therapies include pulmonary rehabilitation, which may improve health-related quality of life and 6-minute walk distance,³⁹ extracorporeal photopheresis,⁴⁰ immunosuppression with calcineurin inhibitors or mycophenolate mofetil,^21,41 and lung transplantation.^42–44 A study with imatinib for the treatment of lung disease in steroid-refractory GVHD has shown promising results, but further validation with larger clinical trials is required.⁴⁵

Case Continued

The patient is diagnosed with BOS and is treated for several months with prednisone 40 mg/day weaned over 3 months. She is started on inhaled corticosteroids, a proton pump inhibitor, and azithromycin 3 times per week, but she has a progressive decline in FEV₁.  She starts pulmonary rehabilitation but continues to functionally decline. Over the next year she develops bilateral pneumothoraces and bilateral cavitary nodules (Figure 1).

• What is causing this decline and the radiographic abnormalities?

Spontaneous air leak syndrome has been described in a little more than 1% of patients undergoing HSCT and has included pneumothorax and mediastinal and subcutaneous emphysema.⁴⁶ It appears that air leak syndrome is more likely to occur in patients with chronic GVHD.⁴⁷ The association between chronic GVHD and air leak syndrome could explain this patient’s recurrent pneumothoraces. The recurrent cavitary nodules are suspicious for infectious etiologies such as nontuberculous mycobacteria, tuberculosis, and fungal infections.

Case Continued

During an episode of pneumothorax, the patient undergoes chest tube placement, pleurodesis, and lung biopsy.  Pathology reveals bronchiolitis obliterans as well as organizing pneumonia (Figure 2). No organisms are seen on acid-fast bacilli or GMS stains.

• What are the other late-onset noninfectious pulmonary complications?

Definitions of other late noninfectious pulmonary complications following HSCT are shown in Table 3.

Interstitial pneumonias may represent COP or may be idiopathic pneumonia syndrome with a later onset or a nonspecific interstitial pneumonia. This syndrome is poorly defined, with a number of differing definitions of the syndrome published in the literature.^50–55

A rare pulmonary complication after HSCT is pulmonary veno-occlusive disease (PVOD). Pulmonary hypertension has been reported after HSCT,⁵⁶ but PVOD is a subset of pulmonary hypertension. It is associated with pleural effusions and volume overload on chest radiography.^57,58 It may present early or late after transplant and is poorly understood.

Besides obstructive and restrictive PFT abnormalities, changes in small airway function⁵⁹ after transplant and loss in diffusing capacity of the lungs for carbon monoxide (Dlco) in the first 5 years after transplant have been reported, although these parameters improve by 10 years after transplant.⁶⁰ There do not appear to be any changes in responsiveness to methacholine.⁶¹ Losses in respiratory muscle strength (PiMax and PeMax after transplant) have been reported.⁶² Lower aerobic exercise capacity (Vo₂max) after pediatric HSCT has also been reported.⁶³

Case Conclusion

The patient’s lung function continues to worsen, but no infectious etiologies are discovered. Ultimately, she dies of respiratory failure caused by progressive bronchiolitis obliterans.

Conclusion

Late pulmonary complications occur frequently in patients who have undergone HSCT. These complications can be classified as infectious versus noninfectious etiologies. Late-onset complications are more common in allogeneic transplantations because they are associated with chronic GVHD. These complications can be manifestations of pulmonary GHVD or can be infectious complications associated with prolonged immunosuppression. Appropriate monitoring for the development of BOS is essential. Early and aggressive treatment of respiratory infections and diagnostic bronchoscopy with BAL can help elucidate most infectious causes. Still, diagnostic challenges remain and multiple causes of respiratory deterioration can be present concurrently in the post-HSCT patient. Steroid therapy remains the mainstay treatment for most noninfectious pulmonary complications and should be strongly considered once infection is effectively ruled out.

ILLUSTRATIVE CASE

Ms. M is a 55-year-old woman who is generally healthy, but who was diagnosed recently with severe vitamin D deficiency (serum 25-hydroxyvitamin D level of 8 ng/mL). She is being seen for her second episode of acute viral bronchitis in the past 6 months. She has no significant smoking or exposure history, no history of asthma, and takes no respiratory medications. Standard treatment for her level of vitamin D deficiency is 50,000 IU/week in bolus dosing, but is that your best option in this case?

Acute respiratory tract infections (ARTIs) include nonspecific upper respiratory illnesses, otitis media, sinusitis (~70% viral), pharyngitis, acute bronchitis (also ~70% viral), influenza, respiratory syncytial virus, and pneumonia.^1,2 In the United States, ARTIs strain the health care system and are the most common cause of ambulatory care visits, accounting for almost 120 million, or about 10% of all visits, per year.³ In addition, ARTIs account for almost 50% of antibiotic prescriptions for adults and almost 75% of antibiotic prescriptions for children—many of which are unnecessary.^2,4

While patient and parent education, antibiotic stewardship programs, and demand management may reduce inappropriate antibiotic use and the overall burden of ARTIs on the health care system, prevention of infections is a powerful tool within the overall approach to managing ARTIs.

STUDY SUMMARY

Vitamin D protects against ARTIs, but only in smaller doses

This 2017 systematic review and meta-analysis of 25 trials (N=10,933) evaluated vitamin D supplementation for the prevention of ARTIs in the primary care setting. Individual participant data were reevaluated to reduce risk of bias. The Cochrane risk of bias tool was used to address threats to validity.

The review and meta-analysis included institutional review board–approved, randomized, double-blind, placebo-controlled trials of vitamin D₃ or vitamin D₂ supplementation of any duration and in any language. The incidence of ARTI was a prespecified efficacy outcome. Duration of the included randomized controlled trials (RCTs) ranged from 7 weeks to 1.5 years.

Outcomes. The primary outcome was an incidence of at least 1 ARTI. Secondary outcomes included incidence of upper and lower ARTIs; incidence of adverse reactions to vitamin D; incidence of emergency department visits or hospital admission or both for ARTI; use of antimicrobials for ARTI; absence from work or school due to ARTI, and mortality (ARTI-related and all-cause).

Findings. Daily or weekly vitamin D supplementation (in doses ranging from < 20 to ≥ 50 µg/d) reduced the risk for ARTI (adjusted odds ratio [AOR] = 0.88; 95% confidence interval [CI], 0.81-0.96; number needed to treat [NNT] = 33). In subgroup analysis, daily or weekly vitamin D was protective (AOR = 0.81; 95% CI, 0.72-0.91), but bolus dosing (≥ 30,000 IU) was not (AOR = 0.97; 95% CI, 0.86-1.10).

Continue to: In 2-step analysis...

This study found that low-dose daily or weekly vitamin D supplementation was protective against acute respiratory tract infections, but bolus dosing was not.

In 2-step analysis, patients benefited who: had baseline circulating 25-hydroxyvitamin D concentrations < 10 ng/mL (AOR = 0.30; 95% CI, 0.17-0.53; NNT = 4); had baseline circulating 25-hydroxyvitamin D levels of 10 to 28 ng/mL (AOR = 0.75; 95% CI, 0.60-0.95; NNT = 15); were ages 1.1 to 15.9 years (AOR = 0.59; 95% CI, 0.45-0.79); were ages 16 to 65 years (AOR = 0.79; 95% CI, 0.63-0.99); or had a body mass index < 25 (AOR = 0.82; 95% CI, 0.71-0.95).

Higher D levels are a different story. Vitamin D supplementation in people with circulating levels of 25-hydroxyvitamin D ≥ 30 ng/mL did not appear to provide benefit (AOR = 0.96; 95% CI, 0.78-1.18). Supplementation in this population did not influence any of the secondary outcomes, including risk for all-cause serious adverse events (AOR = 0.98; 95% CI, 0.80-1.20).

WHAT’S NEW

A more accurate snapshot

Previous studies of vitamin D and respiratory tract infections were mostly observational in nature. Those that were RCTs used variable doses of vitamin D, had variable baseline 25-hydroxyvitamin D levels, and employed various methods to monitor ARTI symptoms/incidence.^5-8 This is the first systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials with supplementation using vitamin D₃ or vitamin D₂ that used individual participant-level data, which gives a more accurate estimate of outcomes when compared with traditional meta-analyses.

CAVEATS

Only the most deficient benefit?

Vitamin D supplementation was safe and protected against ARTIs overall, but the greatest effect of vitamin D supplementation on the prevention of ARTIs was noted in those who were most severely vitamin D deficient (those with circulating 25-hydroxyvitamin levels < 10 ng/mL, NNT = 4; 10-28 ng/mL, NNT = 15). There was no demonstrable effect once circulating 25-hydroxyvitamin D levels reached 30 ng/mL.

CHALLENGES TO IMPLEMENTATION

Breaking tradition

The study found that both daily and weekly doses of vitamin D were effective in reducing the incidence of ARTIs, but the doses used were much lower than the commonly used 10,000 to 50,000 IU bolus doses, which were ineffective in reducing ARTIs in the current meta-analysis. Since bolus dosing is an ingrained practice for many providers, changing this may prove challenging.

Continue to: In addition...

In addition, the authors of the study suggest that one of the ways to provide this level of vitamin D is through food fortification, but food fortification is often complicated by emotional and/or political issues that could thwart implementation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

Ms. M is a 55-year-old woman who is generally healthy, but who was diagnosed recently with severe vitamin D deficiency (serum 25-hydroxyvitamin D level of 8 ng/mL). She is being seen for her second episode of acute viral bronchitis in the past 6 months. She has no significant smoking or exposure history, no history of asthma, and takes no respiratory medications. Standard treatment for her level of vitamin D deficiency is 50,000 IU/week in bolus dosing, but is that your best option in this case?

Acute respiratory tract infections (ARTIs) include nonspecific upper respiratory illnesses, otitis media, sinusitis (~70% viral), pharyngitis, acute bronchitis (also ~70% viral), influenza, respiratory syncytial virus, and pneumonia.^1,2 In the United States, ARTIs strain the health care system and are the most common cause of ambulatory care visits, accounting for almost 120 million, or about 10% of all visits, per year.³ In addition, ARTIs account for almost 50% of antibiotic prescriptions for adults and almost 75% of antibiotic prescriptions for children—many of which are unnecessary.^2,4

While patient and parent education, antibiotic stewardship programs, and demand management may reduce inappropriate antibiotic use and the overall burden of ARTIs on the health care system, prevention of infections is a powerful tool within the overall approach to managing ARTIs.

STUDY SUMMARY

Vitamin D protects against ARTIs, but only in smaller doses

This 2017 systematic review and meta-analysis of 25 trials (N=10,933) evaluated vitamin D supplementation for the prevention of ARTIs in the primary care setting. Individual participant data were reevaluated to reduce risk of bias. The Cochrane risk of bias tool was used to address threats to validity.

The review and meta-analysis included institutional review board–approved, randomized, double-blind, placebo-controlled trials of vitamin D₃ or vitamin D₂ supplementation of any duration and in any language. The incidence of ARTI was a prespecified efficacy outcome. Duration of the included randomized controlled trials (RCTs) ranged from 7 weeks to 1.5 years.

Outcomes. The primary outcome was an incidence of at least 1 ARTI. Secondary outcomes included incidence of upper and lower ARTIs; incidence of adverse reactions to vitamin D; incidence of emergency department visits or hospital admission or both for ARTI; use of antimicrobials for ARTI; absence from work or school due to ARTI, and mortality (ARTI-related and all-cause).

Findings. Daily or weekly vitamin D supplementation (in doses ranging from < 20 to ≥ 50 µg/d) reduced the risk for ARTI (adjusted odds ratio [AOR] = 0.88; 95% confidence interval [CI], 0.81-0.96; number needed to treat [NNT] = 33). In subgroup analysis, daily or weekly vitamin D was protective (AOR = 0.81; 95% CI, 0.72-0.91), but bolus dosing (≥ 30,000 IU) was not (AOR = 0.97; 95% CI, 0.86-1.10).

Continue to: In 2-step analysis...

This study found that low-dose daily or weekly vitamin D supplementation was protective against acute respiratory tract infections, but bolus dosing was not.

In 2-step analysis, patients benefited who: had baseline circulating 25-hydroxyvitamin D concentrations < 10 ng/mL (AOR = 0.30; 95% CI, 0.17-0.53; NNT = 4); had baseline circulating 25-hydroxyvitamin D levels of 10 to 28 ng/mL (AOR = 0.75; 95% CI, 0.60-0.95; NNT = 15); were ages 1.1 to 15.9 years (AOR = 0.59; 95% CI, 0.45-0.79); were ages 16 to 65 years (AOR = 0.79; 95% CI, 0.63-0.99); or had a body mass index < 25 (AOR = 0.82; 95% CI, 0.71-0.95).

Higher D levels are a different story. Vitamin D supplementation in people with circulating levels of 25-hydroxyvitamin D ≥ 30 ng/mL did not appear to provide benefit (AOR = 0.96; 95% CI, 0.78-1.18). Supplementation in this population did not influence any of the secondary outcomes, including risk for all-cause serious adverse events (AOR = 0.98; 95% CI, 0.80-1.20).

WHAT’S NEW

A more accurate snapshot

Previous studies of vitamin D and respiratory tract infections were mostly observational in nature. Those that were RCTs used variable doses of vitamin D, had variable baseline 25-hydroxyvitamin D levels, and employed various methods to monitor ARTI symptoms/incidence.^5-8 This is the first systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials with supplementation using vitamin D₃ or vitamin D₂ that used individual participant-level data, which gives a more accurate estimate of outcomes when compared with traditional meta-analyses.

CAVEATS

Only the most deficient benefit?

Vitamin D supplementation was safe and protected against ARTIs overall, but the greatest effect of vitamin D supplementation on the prevention of ARTIs was noted in those who were most severely vitamin D deficient (those with circulating 25-hydroxyvitamin levels < 10 ng/mL, NNT = 4; 10-28 ng/mL, NNT = 15). There was no demonstrable effect once circulating 25-hydroxyvitamin D levels reached 30 ng/mL.

CHALLENGES TO IMPLEMENTATION

Breaking tradition

The study found that both daily and weekly doses of vitamin D were effective in reducing the incidence of ARTIs, but the doses used were much lower than the commonly used 10,000 to 50,000 IU bolus doses, which were ineffective in reducing ARTIs in the current meta-analysis. Since bolus dosing is an ingrained practice for many providers, changing this may prove challenging.

Continue to: In addition...

In addition, the authors of the study suggest that one of the ways to provide this level of vitamin D is through food fortification, but food fortification is often complicated by emotional and/or political issues that could thwart implementation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

Ms. M is a 55-year-old woman who is generally healthy, but who was diagnosed recently with severe vitamin D deficiency (serum 25-hydroxyvitamin D level of 8 ng/mL). She is being seen for her second episode of acute viral bronchitis in the past 6 months. She has no significant smoking or exposure history, no history of asthma, and takes no respiratory medications. Standard treatment for her level of vitamin D deficiency is 50,000 IU/week in bolus dosing, but is that your best option in this case?

Acute respiratory tract infections (ARTIs) include nonspecific upper respiratory illnesses, otitis media, sinusitis (~70% viral), pharyngitis, acute bronchitis (also ~70% viral), influenza, respiratory syncytial virus, and pneumonia.^1,2 In the United States, ARTIs strain the health care system and are the most common cause of ambulatory care visits, accounting for almost 120 million, or about 10% of all visits, per year.³ In addition, ARTIs account for almost 50% of antibiotic prescriptions for adults and almost 75% of antibiotic prescriptions for children—many of which are unnecessary.^2,4

While patient and parent education, antibiotic stewardship programs, and demand management may reduce inappropriate antibiotic use and the overall burden of ARTIs on the health care system, prevention of infections is a powerful tool within the overall approach to managing ARTIs.

STUDY SUMMARY

Vitamin D protects against ARTIs, but only in smaller doses

This 2017 systematic review and meta-analysis of 25 trials (N=10,933) evaluated vitamin D supplementation for the prevention of ARTIs in the primary care setting. Individual participant data were reevaluated to reduce risk of bias. The Cochrane risk of bias tool was used to address threats to validity.

The review and meta-analysis included institutional review board–approved, randomized, double-blind, placebo-controlled trials of vitamin D₃ or vitamin D₂ supplementation of any duration and in any language. The incidence of ARTI was a prespecified efficacy outcome. Duration of the included randomized controlled trials (RCTs) ranged from 7 weeks to 1.5 years.

Outcomes. The primary outcome was an incidence of at least 1 ARTI. Secondary outcomes included incidence of upper and lower ARTIs; incidence of adverse reactions to vitamin D; incidence of emergency department visits or hospital admission or both for ARTI; use of antimicrobials for ARTI; absence from work or school due to ARTI, and mortality (ARTI-related and all-cause).

Findings. Daily or weekly vitamin D supplementation (in doses ranging from < 20 to ≥ 50 µg/d) reduced the risk for ARTI (adjusted odds ratio [AOR] = 0.88; 95% confidence interval [CI], 0.81-0.96; number needed to treat [NNT] = 33). In subgroup analysis, daily or weekly vitamin D was protective (AOR = 0.81; 95% CI, 0.72-0.91), but bolus dosing (≥ 30,000 IU) was not (AOR = 0.97; 95% CI, 0.86-1.10).

Continue to: In 2-step analysis...

This study found that low-dose daily or weekly vitamin D supplementation was protective against acute respiratory tract infections, but bolus dosing was not.

In 2-step analysis, patients benefited who: had baseline circulating 25-hydroxyvitamin D concentrations < 10 ng/mL (AOR = 0.30; 95% CI, 0.17-0.53; NNT = 4); had baseline circulating 25-hydroxyvitamin D levels of 10 to 28 ng/mL (AOR = 0.75; 95% CI, 0.60-0.95; NNT = 15); were ages 1.1 to 15.9 years (AOR = 0.59; 95% CI, 0.45-0.79); were ages 16 to 65 years (AOR = 0.79; 95% CI, 0.63-0.99); or had a body mass index < 25 (AOR = 0.82; 95% CI, 0.71-0.95).

Higher D levels are a different story. Vitamin D supplementation in people with circulating levels of 25-hydroxyvitamin D ≥ 30 ng/mL did not appear to provide benefit (AOR = 0.96; 95% CI, 0.78-1.18). Supplementation in this population did not influence any of the secondary outcomes, including risk for all-cause serious adverse events (AOR = 0.98; 95% CI, 0.80-1.20).

WHAT’S NEW

A more accurate snapshot

Previous studies of vitamin D and respiratory tract infections were mostly observational in nature. Those that were RCTs used variable doses of vitamin D, had variable baseline 25-hydroxyvitamin D levels, and employed various methods to monitor ARTI symptoms/incidence.^5-8 This is the first systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials with supplementation using vitamin D₃ or vitamin D₂ that used individual participant-level data, which gives a more accurate estimate of outcomes when compared with traditional meta-analyses.

CAVEATS

Only the most deficient benefit?

Vitamin D supplementation was safe and protected against ARTIs overall, but the greatest effect of vitamin D supplementation on the prevention of ARTIs was noted in those who were most severely vitamin D deficient (those with circulating 25-hydroxyvitamin levels < 10 ng/mL, NNT = 4; 10-28 ng/mL, NNT = 15). There was no demonstrable effect once circulating 25-hydroxyvitamin D levels reached 30 ng/mL.

CHALLENGES TO IMPLEMENTATION

Breaking tradition

The study found that both daily and weekly doses of vitamin D were effective in reducing the incidence of ARTIs, but the doses used were much lower than the commonly used 10,000 to 50,000 IU bolus doses, which were ineffective in reducing ARTIs in the current meta-analysis. Since bolus dosing is an ingrained practice for many providers, changing this may prove challenging.

Continue to: In addition...

In addition, the authors of the study suggest that one of the ways to provide this level of vitamin D is through food fortification, but food fortification is often complicated by emotional and/or political issues that could thwart implementation.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Hematopoietic stem cell transplantation (HSCT) is widely used in the economically developed world to treat a variety of hematologic malignancies as well as nonmalignant diseases and solid tumors. An estimated 17,900 HSCTs were performed in 2011, and survival rates continue to increase.¹ Pulmonary complications post HSCT are common, with rates ranging from 40% to 60%, and are associated with increased morbidity and mortality.²

Clinical diagnosis of pulmonary complications in the HSCT population has been aided by a previously well-defined chronology of the most common diseases.³ Historically, early pulmonary complications were defined as pulmonary complications occurring within 100 days of HSCT (corresponding to the acute graft-versus-host disease [GVHD] period). Late pulmonary complications are those that occur thereafter. This timeline, however, is now more variable given the increasing indications for HSCT, the use of reduced-intensity conditioning strategies, and varied individual immune reconstitution. This article discusses the management of early post-HSCT pulmonary complications; late post-HSCT pulmonary complications will be discussed in a separate follow-up article.

Transplant Basics

The development of pulmonary complications is affected by many factors associated with the transplant. Autologous transplantation involves the collection of a patient’s own stem cells, appropriate storage and processing, and re-implantation after induction therapy. During induction therapy, the patient undergoes high-dose chemotherapy or radiation therapy that ablates the bone marrow. The stem cells are then transfused back into the patient to repopulate the bone marrow. Allogeneic transplants involve the collection of stem cells from a donor. Donors are matched as closely as possible to the recipient’s histocompatibility antigen (HLA) haplotypes to prevent graft failure and rejection. The donor can be related or unrelated to the recipient. If there is not a possibility of a related match (from a sibling), then a national search is undertaken to look for a match through the National Marrow Donor Program. There are fewer transplant reactions and occurrences of GVHD if the major HLAs of the donor and recipient match. Table 1 reviews basic definitions pertaining to HSCT.

How the cells for transplantation are obtained is also an important factor in the rate of complications. There are 3 main sources: peripheral blood, bone marrow, and umbilical cord. Peripheral stem cell harvesting involves exposing the donor to granulocyte-colony stimulating factor (gCSF), which increases peripheral circulation of stem cells. These cells are then collected and infused into the recipient after the recipient has completed an induction regimen involving chemotherapy and/or radiation, depending on the protocol. This procedure is called peripheral blood stem cell transplant (PBSCT). Stem cells can also be directly harvested from bone marrow cells, which are collected from repeated aspiration of bone marrow from the posterior iliac crest.⁴ This technique is most common in children, whereas in adults peripheral blood stem cells are the most common source. Overall mortality does not differ based on the source of the stem cells. It is postulated that GVHD may be more common in patients undergoing PBSCT, but the graft failure rate may be lower.⁵

The third option is umbilical cord blood (UCB) as the source of stem cells. This involves the collection of umbilical cord blood that is prepared and frozen after birth. It has a smaller volume of cells, and although fewer cells are needed when using UCB, 2 separate donors may be required for a single adult recipient. The engraftment of the stem cells is slower and infections in the post-transplant period are more common. Prior reports indicate GVHD rates may be lower.⁴ While the use of UCB is not common in adults, the incidence has doubled over the past decade, increasing from 3% to 6%.

The conditioning regimen can influence pulmonary complications. Traditionally, an ablative transplant involves high-dose chemotherapy or radiation to eradicate the recipient’s bone marrow. This regimen can lead to many complications, especially in the immediate post-transplant period. In the past 10 years, there has been increasing interest in non-myeloablative, or reduced-intensity, conditioning transplants.⁶ These “mini transplants” involve smaller doses of chemotherapy or radiation, which do not totally eradicate the bone marrow; after the transplant a degree of chimerism develops where the donor and recipient stem cells coexist. The medications in the preparative regimen also should be considered because they can affect pulmonary complications after transplant. Certain chemotherapeutic agents such as carmustine, bleomycin, and many others can lead to acute and chronic presentations of pulmonary diseases such as hypersensitivity pneumonitis, pulmonary fibrosis, acute respiratory distress syndrome, and abnormal pulmonary function testing.

After the HSCT, GVHD can develop in more than 50% of allogeneic recipients.³ The incidence of GVHD has been reported to be increasing over the past 12 years.It is divided into acute GVHD (which traditionally happens in the first 100 days after transplant) and chronic GVHD (after day 100). This calendar-day–based system has been augmented based on a 2006 National Institutes of Health working group report emphasizing the importance of organ-specific features of chronic GVHD in the clinical presentation of GVHD.⁷ Histologic changes in chronic organ GVHD tend to include more fibrotic features, whereas in acute GVHD more inflammatory changes are seen. The NIH working group report also stressed the importance of obtaining a biopsy specimen for histopathologic review and interdisciplinary collaboration to arrive at a consensus diagnosis, and noted the limitations of using histologic changes as the sole determinant of a “gold standard” diagnosis.⁷ GVHD can directly predispose patients to pulmonary GVHD and indirectly predispose them to infectious complications because the mainstay of therapy for GVHD is increased immunosuppression.

Pretransplant Evaluation

Case Patient 1

A 56-year-old man is diagnosed with acute myeloid leukemia (AML) after presenting with signs and symptoms consistent with pancytopenia. He has a past medical history of chronic sinus congestion, arthritis, depression, chronic pain, and carpal tunnel surgery. He is employed as an oilfield worker and has a 40-pack-year smoking history, but he recently cut back to half a pack per day. He is being evaluated for allogeneic transplant with his brother as the donor and the planned conditioning regimen is total body irradiation (TBI), thiotepa, cyclophosphamide, and antithymocyte globulin with T-cell depletion. Routine pretransplant pulmonary function testing (PFT) reveals a restrictive pattern and he is sent for pretransplant pulmonary evaluation.

Physical exam reveals a chronically ill appearing man. He is afebrile, the respiratory rate is 16 breaths/min, blood pressure is 145/88 mm Hg, heart rate is 92 beats/min, and oxygen saturation is 95%. He is in no distress. Auscultation of the chest reveals slightly diminished breath sounds bilaterally but is clear and without wheezes, rhonchi, or rales. Heart exam shows regular rate and rhythm without murmurs, rubs, or gallops. Extremities reveal no edema or rashes. Otherwise, the remainder of the exam is normal. The patient’s PFT results are shown in Table 2.

• What aspects of this patient’s history put him at risk for pulmonary complications after transplantation?

Risk Factors for Pulmonary Complications

Predicting who is at risk for pulmonary complications is difficult. Complications are generally divided into infectious and noninfectious categories. Regardless of category, allogeneic HSCT recipients are at increased risk compared with autologous recipients, but even in autologous transplants, more than 25% of patients will develop pulmonary complications in the first year.⁸ Prior to transplant, patients undergo full PFT. Early on, many studies attempted to show relationships between various factors and post-transplant pulmonary complications. Factors that were implicated were forced expiratory volume in 1 second (FEV₁), diffusing capacity of the lung for carbon monoxide (Dlco), total lung capacity (TLC), GVHD prophylaxis, TBI, and FEV₁/forced vital capacity (FEV₁/FVC) ratio.^9-15 Generally, poor baseline pulmonary functional status has been shown to correlate with higher risk for pulmonary complications. The most widely accepted pre-transplant PFT values examined for determining risk for developing pulmonary complications are FEV₁ and Dlco.

Another sometimes overlooked risk before transplantation is restrictive lung disease. One study showed a twofold increase in respiratory failure and mortality if there was pretransplant restriction based on TLC < 80%.¹⁶

An interesting study by one group in pretransplant evaluation found decreased muscle strength by maximal inspiratory muscle strength (PImax), maximal expiratory muscle strength (PEmax), dominant hand grip strength, and 6-minute walk test (6MWT) distance prior to allogeneic transplant, but did not find a relationship between these variables and mortality.¹⁷ While this study had a small sample size, these findings likely deserve continued investigation.¹⁸

• What methods are used to calculate risk for complications?

Risk Scoring Systems

Several pretransplantation risk scores have been developed. In a study that looked at more than 2500 allogeneic transplants, Parimon et al showed that risk of mortality and respiratory failure could be estimated prior to transplant using a scoring system—the Lung Function Score (LFS)—that combines the FEV₁ and Dlco.¹⁹ They assigned a score to the FEV₁ and Dlco based on the percentage of predicted values on PFT. Values greater than 80% were assigned 1 point, values 70% to 80% 2 points, 60% to 70% 3 points, and less than 60% 4 points. Combining the values for the FEV₁ and Dlco provides the LFS. A normal score is 2 (1 point each for FEV₁ and Dlco values > 80%) and is category I. A score of 3–4 is mildly decreased, category II; a score of 5–6 is moderately decreased, category III; and 7–8 is severely decreased, category IV. The hazard ratios (HR) for acute respiratory failure after transplant were 1.4, 2.2, and 3.1 for categories II, III, and IV, respectively. The HRs for mortality were 1.2, 2.2, and 2.7 for the same categories.¹⁹ This LFS has been used post-transplantation as well to categorize pulmonary GVHD.²⁰

The Pretransplantation Assessment of Mortality score, initially developed in 2006, predicts mortality within the first 2 years after HSCT based on 8 clinical factors: disease risk, age at transplant, donor type, conditioning regimen, and markers of organ function (percentage of predicted FEV₁, percentage of predicted Dlco, serum creatinine level, serum alanine aminotransferase level). Given the increased use of reduced-intensity conditioning regimens, the authors reevaluated the PAM score and following this analysis, creatinine, percent predicted Dlco, and liver function tests were found to no longer be statistically significant and were removed from the PAM score in 2015.^21,22 Another widely used score is the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI),²³ which predicts mortality following allogeneic stem cell transplantation. The HCT-CI also uses the FEV₁ and the Dlco as the 2 objective measures of pulmonary function.²³ While these pulmonary tests help with risk stratification, they are not perfect and it is not advised to use an isolated low Dlco to exclude individuals from transplant.²⁴ Recently, Coffey et al looked at the practice of correcting Dlco for hemoglobin by the Cotes method as suggested by the American Thoracic Society (ATS) versus the Dinakara method that was used in the HCT-CI.²⁵ In this study, the use of the Cotes method resulted in an elevated HCT-CI in 45% of patients, and in 33% it resulted in higher mortality risk predictions. Since the HCT-CI is validated using the Dinakara method, that method should be used in the HCT-CI calculations.²⁵

• What other preoperative testing or interventions should be considered in this patient?

Since there is a high risk of infectious complications after transplant, the question of whether pretransplantation patients should undergo screening imaging may arise. There is no evidence that routine chest computed tomography (CT) reduces the risk of infectious complications after transplantation.²⁶ An area that may be insufficiently addressed in the pretransplantation evaluation is smoking cessation counseling.²⁷ Studies have shown an elevated risk of mortality in smokers.^28-30 Others have found a higher incidence of respiratory failure but not an increased mortality.³¹ Overall, with the good rates of smoking cessation that can be accomplished, smokers should be counseled to quit before transplantation.

In summary, patients should undergo full PFTs prior to transplantation to help stratify risk for pulmonary complications and mortality and to establish a clinical baseline. The LFS (using FEV₁ and Dlco) can help categorize risk of respiratory failure and mortality after transplant. Absolute cut-off values for FEV₁ and Dlco are debated, but < 40% predicted and < 30% to 40% predicted, respectively, are considered contraindications to transplant. Smoking cessation should be advised if applicable during the pretransplant visit and optimization of reversible lung conditions should be stressed. There are no formal recommendations about reducing risk of early complications, but early mobilization, incentive spirometry, and use of inhalers if there is any history of obstructive lung disease should be considered.

Case Patient 1 Conclusion

The patient undergoes transplantation due to his lack of other treatment options. Evaluation prior to transplant, however, shows that he is at high risk for pulmonary complications. He has a LFS of 7 prior to transplant (using the Dlco corrected for hemoglobin), which puts him in class IV, with a HR of 3.1 for early respiratory failure and a HR of 2.7 for mortality. Additionally, he is still smoking at the time of transplantation. He does well immediately after transplantation, but has a complicated course with worsening mixed restrictive and obstructive pulmonary function abnormality. He becomes oxygen dependent and eventually undergoes video-assisted thoracoscopic surgery (VATS), which shows both usual interstitial pneumonia and restrictive bronchiolitis with changes consistent with mild to moderate pulmonary hypertension. He dies 2 years to the month after transplantation.

Early Infectious Pulmonary Complications

Case Patient 2

A 27-year-old man with a medical history significant for AML and allogeneic HSCT presents with cough productive of a small amount of clear to white sputum, dyspnea on exertion, and fevers for 1 week. He also has mild nausea and a decrease in appetite. He underwent HSCT 2.5 months prior to admission, which was a matched unrelated bone marrow transplant with TBI and cyclophosphamide conditioning. His past medical history is significant only for exercise-induced asthma for which he takes a rescue inhaler infrequently prior to transplantation. His pretransplant PFTs showed normal spirometry with an FEV₁ of 106% of predicted and Dlco of 54% of predicted. He does not smoke. His post-transplant medical course was complicated by severe acute skin GVHD as well as diarrhea, with sigmoidoscopy showing GVHD.

Physical exam is notable for fever of 101.0°F, heart rate 80 beats/min, respiratory rate 16 breaths/ min, and blood pressure 142/78 mm Hg; an admission oxygen saturation is 93% on room air. Lungs show bibasilar crackles and the remainder of the exam is normal. Laboratory testing shows a white blood cell count of 2400 cells/μL, hemoglobin 7.6 g/dL, and platelet count 66 × 10³/μL. Creatinine is 1.0 mg/dL. Chest radiograph shows ill-defined bilateral lower-lobe infiltrates. CT scans are shown in the Figure.

• For which infectious complications is this patient most at risk?

Pneumonia

A prospective trial in the HSCT population reported a pneumonia incidence rate of 68%, and pneumonia is more common in allogeneic HSCT with prolonged immunosuppressive therapy.³² Development of pneumonia within 100 days of transplant directly correlates with nonrelapsed mortality.³³ Early detection is key, and bronchoscopy within the first 5 days of symptoms has been shown to change therapy in approximately 40% of cases but has not been shown to affect mortality.³⁴ The clinical presentation of pneumonia in the HSCT population can be variable because of the presence of neutropenia and profound immunosuppression. Traditionally accepted diagnostic criteria of fevers, sputum production, and new infiltrates should be used with caution, and an appropriately high index of suspicion should be maintained. Progression to respiratory failure, regardless of causative organism of infection, portends a poor prognosis, with mortality rates estimated at 70% to 90%.^35,36 Several transplant-specific factors may affect early infections. For instance, UCB transplants have been found to have a higher incidence of invasive aspergillosis and cytomegalovirus (CMV) infections but without higher mortality attributed to the infections.³⁷

Bacterial Pneumonia

Bacterial pneumonia accounts for 20% to 50% of pneumonia cases in HSCT recipients.³⁸ Gram-negative organisms, specifically Pseudomonas aeruginosa and Escherichia coli, were reported to be the most common pathologic bacteria in recent prospective trials, whereas previous retrospective trials showed that common community-acquired organisms were the most common cause of pneumonia in HSCT recipients.^32,39 This underscores the importance of being aware of the clinical prevalence of microorganisms and local antibiograms, along with associated institutional susceptibility profiles. Initiation of immediate empiric broad-spectrum antibiotics is essential when bacterial pneumonia is suspected.

Viral Pneumonia

The prevalence of viral pneumonia in stem cell transplant recipients is estimated at 28%,³² with most cases being caused by community viral pathogens such as rhinovirus, respiratory syncytial virus (RSV), influenza A and B, and parainfluenza.³⁹ The prevention, prophylaxis, and early treatment of viral pneumonias, specifically CMV infection, have decreased the mortality associated with early pneumonia after HSCT. Co-infection with bacterial organisms must be considered and has been associated with increased mortality in the intensive care unit setting.⁴⁰

Supportive treatment with rhinovirus infection is sufficient as the disease is usually self-limited in immunocompromised patients. In contrast, infection with RSV in the lower respiratory tract is associated with increased mortality in prior reports, and recent studies suggest that further exploration of prophylaxis strategies is warranted.⁴¹ Treatment with ribavirin remains the backbone of therapy, but drug toxicity continues to limit its use. The addition of immunomodulators such as RSV immune globulin or palivizumab to ribavirin remains controversial, but a retrospective review suggests that early treatment may prevent progression to lower respiratory tract infection and lead to improved mortality.⁴² Infection with influenza A/B must be considered during influenza season. Treatment with oseltamivir may shorten the duration of disease when influenza A/B or parainfluenza are detected. Reactivation of latent herpes simplex virus during the pre-engraftment phase should also be considered. Treatment is similar to that in nonimmunocompromised hosts. When CMV pneumonia is suspected, careful history regarding compliance with prophylactic antivirals and CMV status of both the recipient and donor are key. A presumptive diagnosis can be made with the presence of appropriate clinical scenario, supportive radiographic images showing areas of ground-glass opacification or consolidation, and positive CMV polymerase chain reaction (PCR) assay. Visualization of inclusion bodies on lung biopsy tissue remains the gold standard for diagnosis. Treatment consists of CMV immunoglobulin and ganciclovir.

Fungal Pneumonia

Early fungal pneumonias have been associated with increased mortality in the HSCT population.⁴³ Clinical suspicion should remain high and compliance with antifungal prophylaxis should be questioned thoroughly. Invasive aspergillosis (IA) remains the most common fungal infection. A bimodal distribution of onset of infection peaking on day 16 and again on day 96 has been described in the literature.⁴⁴ Patients often present with classic pneumonia symptoms, but these may be accompanied by hemoptysis. Proven IA diagnosis requires visualization of fungal forms from biopsy or needle aspiration or a positive culture obtained in a sterile fashion.⁴⁵ Most clinical data comes from experience with probable and possible diagnosis of IA. Bronchoalveolar lavage with testing with Aspergillus galactomannan assay has been shown to be clinically useful in establishing the clinical diagnosis in the HSCT population.⁴⁶ Classic air-crescent findings on chest CT are helpful in establishing a possible diagnosis, but retrospective analysis reveals CT findings such as focal infiltrates and pulmonary nodular patterns are more common.⁴⁷ First-line treatment with voriconazole has been shown to decrease short-term mortality attributable to IA but has not had an effect on long-term, all-cause mortality.⁴⁸ Surgical resection is reserved for patients with refractory disease or patients presenting with massive hemoptysis.

Mucormycosis is an emerging disease with ever increasing prevalence in the HSCT population, reflecting the improved prophylaxis and treatment of IA. Initial clinical presentation is similar to IA, most commonly affecting the lung, although craniofacial involvement is classic for mucormycosis, especially in HSCT patients with diabetes.⁴⁹Mucor infections can present with massive hemoptysis due to tissue invasion and disregard for tissue and fascial planes. Diagnosis of mucormycosis is associated with as much as a six-fold increase in risk for death. Diagnosis requires identification of the organism by examination or culture and biopsy is often necessary.^50,51 Amphotericin B remains first-line therapy as mucormycosis is resistant to azole antifungals, with higher doses recommended for cerebral involvement.⁵²

Candida pulmonary infections during the early HSCT period are becoming increasingly rare due to widespread use of fluconazole prophylaxis and early treatment of mucosal involvement during neutropenia. Endemic fungal infections such as blastomycosis, coccidioidomycosis, and histoplasmosis should be considered in patients inhabiting specific geographic areas or with recent travel to these areas.

• What test should be performed to evaluate for infectious causes of pneumonia?

Role of Flexible Fiberoptic Bronchoscopy

The utility of flexible fiberoptic bronchoscopy (FOB) in immune-compromised patients for the evaluation of pulmonary infiltrates is a frequently debated topic. Current studies suggest a diagnosis can be made in approximately 80% of cases in the immune-compromised population.^32,53 Noninvasive testing such as urine and serum antigens, sputum cultures, Aspergillus galactomannan assays, viral nasal swabs, and PCR studies often lead to a diagnosis in appropriate clinical scenarios. Conservative management would dictate the use of noninvasive testing whenever possible, and randomized controlled trials have shown noninvasive testing to be noninferior to FOB in preventing need for mechanical ventilation, with no difference in overall mortality.⁵⁴ FOB has been shown to be most useful in establishing a diagnosis when an infectious etiology is suspected.⁵⁵ In multivariate analysis, a delay in the identification of the etiology of pulmonary infiltrate was associated with increased mortality.⁵⁶ Additionally, early FOB was found to be superior to late FOB in revealing a diagnosis. ^32,57 Despite its ability to detect the cause of pulmonary disease, direct antibiotic therapy, and possibly change therapy, FOB with diagnostic maneuvers has not been shown to affect mortality.⁵⁸ In a large case series, FOB with bronchoalveolar lavage (BAL) revealed a diagnosis in approximately 30% to 50% of cases. The addition of transbronchial biopsy did not improve diagnostic utility.⁵⁸ More recent studies have confirmed that the addition of transbronchial biopsy does not add to diagnostic yield and is associated with increased adverse events.⁵⁹ The appropriate use of advanced techniques such as endobronchial ultrasound–guided transbronchial needle aspirations, endobronchial biopsy, and CT-guided navigational bronchoscopy has not been established and should be considered on a case-by-case basis. In summary, routine early BAL is the diagnostic test of choice, especially when infectious pulmonary complications are suspected.

Contraindications for FOB in this population mirror those in the general population. These include acute severe hypoxemic respiratory failure, myocardial ischemia or acute coronary syndrome within 2 weeks of procedure, severe thrombocytopenia, and inability to provide or obtain informed consent from patient or health care power of attorney. Coagulopathy and thrombocytopenia are common comorbid conditions in the HSCT population. A platelet count of < 20 × 10³/µL has generally been used as a cut-off for routine FOB with BAL.⁶⁰ Risks of the procedures should be discussed clearly with the patient, but simple FOB for airway evaluation and BAL is generally well tolerated even under these conditions.

Early Nonifectious Pulmonary Complications

Case Patient 2 Continued

Bronchoscopy with BAL performed the day after admission is unremarkable and stains and cultures are negative for viral, bacterial, and fungal organisms. The patient is initially started on broad-spectrum antibiotics, but his oxygenation continues to worsen to the point that he is placed on noninvasive positive pressure ventilation. He is started empirically on amphotericin B and eventually is intubated. VATS lung biopsy is ultimately performed and pathology is consistent with diffuse alveolar damage.

• Based on these biopsy findings, what is the diagnosis?

Based on the pathology consistent with diffuse alveolar damage, a diagnosis of idiopathic pneumonia syndrome (IPS) is made.

• What noninfectious pulmonary complications occur in the early post-transplant period?

The overall incidence of noninfectious pulmonary complications after HSCT is generally estimated at 20% to 30%.³² Acute pulmonary edema is a common very early noninfectious pulmonary complication and clinically the most straightforward to treat. Three distinct clinical syndromes—peri-engraftment respiratory distress syndrome (PERDS), diffuse alveolar hemorrhage (DAH), and IPS—comprise the remainder of the pertinent early noninfectious complications. Clinical presentation differs based upon the disease entity. Recent studies have evaluated the role of angiotensin-converting enzyme polymorphisms as a predictive marker for risk of developing early noninfectious pulmonary complications.⁶¹

Peri-Engraftment Respiratory Distress Syndrome

PERDS is a clinical syndrome comprising the cardinal features of erythematous rash and fever along with noncardiogenic pulmonary infiltrates and hypoxemia that occur in the peri-engraftment period, defined as recovery of absolute neutrophil count to > 500/μL on 2 consecutive days.⁶² PERDS occurs in the autologous HSCT population and may be a clinical correlate to early GVHD in the allogeneic HSCT population. It is hypothesized that the pathophysiology underlying PERDS is an autoimmune-related capillary leak caused by pro-inflammatory cytokine release.⁶³ Treatment remains anecdotal and currently consists of supportive care and high-dose corticosteroids. Some have favored limiting the use of gCSF given its role in stimulating rapid white blood cell recovery.³³ Prognosis is favorable, but progression to fulminant respiratory failure requiring mechanical ventilation portends a poor prognosis.

Diffuse Alveolar Hemorrhage

DAH is clinical syndrome consisting of diffuse alveolar infiltrates on pulmonary imaging combined with progressively bloodier return per aliquot during BAL in 3 different subsegments or more than 20% hemosiderin-laden macrophages on BAL fluid evaluation. Classically, DAH is defined in the absence of pulmonary infection or cardiac dysfunction. The pathophysiology is thought to be related to inflammation of pulmonary vasculature within the alveolar walls leading to alveolitis. Although no prospective trials exist, early use of high-dose corticosteroid therapy is thought to improve outcomes;^64,65 a recent study, however, showed low-dose steroids may be associated with the lowest mortality.⁶⁶ Mortality is directly linked to the presence of superimposed infection, need for mechanical ventilation, late onset, and development of multiorgan failure.⁶⁷

Idiopathic Pneumonia Syndrome

IPS is a complex clinical syndrome whose pathology is felt to stem from a variety of possible lung insults such as direct myeloablative drug toxicity, occult pulmonary infection, or cytokine-driven inflammation. The ATS published an article further subcategorizing IPS as different clinical entities based upon whether the primary insult involves the vascular endothelium, interstitial tissue, and airway tissue, truly idiopathic, or unclassified.⁶⁸ In clinical practice, IPS is defined as widespread alveolar injury in the absence of evidence of renal failure, heart failure, and excessive fluid resuscitation. In addition, negative testing for a variety of bacterial, viral, and fungal causes is also necessary.⁶⁹ Clinical syndromes included within the IPS definition are ARDS, acute interstitial pneumonia, DAH, cryptogenic organizing pneumonia, and BOS.⁷⁰ Risk factors for developing IPS include TBI, older age of recipient, acute GVHD, and underlying diagnosis of AML or myelodysplastic syndrome.¹² In addition, it has been shown that risk for developing IPS is lower in patients undergoing allogeneic HSCT who receive non-myeloablative conditioning regimens.⁷¹ The pathologic finding in IPS is diffuse alveolar damage. A 2006 study in which investigators reviewed BAL samples from patients with IPS found that 3% of the patients had PCR evidence of human metapneumovirus infection, and a study in 2015 found PCR evidence of infection in 53% of BAL samples from patients diagnosed with IPS.^72,73 This fuels the debate on whether IPS is truly an infection-driven process where the source of infection, pulmonary or otherwise, simply escapes detection. Various surfactant proteins, which play a role in decreasing surface tension within the alveolar interface and function as mediators within the innate immunity of the lung, have been studied in regard to development of IPS. Small retrospective studies have shown a trend toward lower pre-transplant serum protein surfactant D and the development of IPS.⁷⁴

The diagnosis of IPS does not require pathologic diagnosis in most circumstances. The correct clinical findings in association with a negative infectious workup lead to a presumptive diagnosis of IPS. The extent of the infectious workup that must be completed to adequately rule out infection is often a difficult clinical question. Recent recommendations include BAL fluid evaluation for routine bacterial cultures, appropriate viral culture, and consideration of PCR testing to evaluate for Mycoplasma, Chlamydia, and Aspergillus antigens.⁷⁵ Transbronchial biopsy continues to appear in recommendations, but is not routinely performed and should be completed as the patient’s clinical status permits.^8,68 Table 3 reviews basic features of early noninfectious pulmonary complications.

• What treatment should be offered to the patient with diffuse alveolar damage on biopsy?

Treatment consists of supportive care and empiric broad-spectrum antibiotics with consideration of high-dose corticosteroids. Based upon early studies in murine models implicating TNF, pilot studies were performed evaluating etanercept as a possible safe and effective addition to high-dose systemic corticosteroids.⁷⁷ Although these results were promising, data from a truncated randomized control clinical trial failed to show improvement in patient response in the adult population.⁷⁶ More recent data from the same author suggests that pediatric populations with IPS are, however, responsive to etanercept and high-dose corticosteroid therapy.⁷⁸ When IPS develops as a late complication, treatment with high-dose corticosteroids (2 mg/kg/day) and etanercept (0.4 mg/kg twice weekly) has been shown to improve 2-year survival.⁷⁹

Case Patient 2 Conclusion

The patient is started on steroids and makes a speedy recovery. He is successfully extubated 5 days later.

Conclusion

Careful pretransplant evaluation, including a full set of pulmonary function tests, can help predict a patient’s risk for pulmonary complications after transplant, allowing risk factor modification strategies to be implemented prior to transplant, including smoking cessation. It also helps identify patients at high risk for complications who will require closer monitoring after transplantation. Early posttransplant complications include infectious and noninfectious entities. Bacterial, viral, and fungal pneumonias are in the differential of infectious pneumonia, and bronchoscopy can be helpful in establishing a diagnosis. A common, important noninfectious cause of early pulmonary complications is IPS, which is treated with steroids and sometimes anti-TNF therapy.

Hematopoietic stem cell transplantation (HSCT) is widely used in the economically developed world to treat a variety of hematologic malignancies as well as nonmalignant diseases and solid tumors. An estimated 17,900 HSCTs were performed in 2011, and survival rates continue to increase.¹ Pulmonary complications post HSCT are common, with rates ranging from 40% to 60%, and are associated with increased morbidity and mortality.²

Clinical diagnosis of pulmonary complications in the HSCT population has been aided by a previously well-defined chronology of the most common diseases.³ Historically, early pulmonary complications were defined as pulmonary complications occurring within 100 days of HSCT (corresponding to the acute graft-versus-host disease [GVHD] period). Late pulmonary complications are those that occur thereafter. This timeline, however, is now more variable given the increasing indications for HSCT, the use of reduced-intensity conditioning strategies, and varied individual immune reconstitution. This article discusses the management of early post-HSCT pulmonary complications; late post-HSCT pulmonary complications will be discussed in a separate follow-up article.

Transplant Basics

The development of pulmonary complications is affected by many factors associated with the transplant. Autologous transplantation involves the collection of a patient’s own stem cells, appropriate storage and processing, and re-implantation after induction therapy. During induction therapy, the patient undergoes high-dose chemotherapy or radiation therapy that ablates the bone marrow. The stem cells are then transfused back into the patient to repopulate the bone marrow. Allogeneic transplants involve the collection of stem cells from a donor. Donors are matched as closely as possible to the recipient’s histocompatibility antigen (HLA) haplotypes to prevent graft failure and rejection. The donor can be related or unrelated to the recipient. If there is not a possibility of a related match (from a sibling), then a national search is undertaken to look for a match through the National Marrow Donor Program. There are fewer transplant reactions and occurrences of GVHD if the major HLAs of the donor and recipient match. Table 1 reviews basic definitions pertaining to HSCT.

How the cells for transplantation are obtained is also an important factor in the rate of complications. There are 3 main sources: peripheral blood, bone marrow, and umbilical cord. Peripheral stem cell harvesting involves exposing the donor to granulocyte-colony stimulating factor (gCSF), which increases peripheral circulation of stem cells. These cells are then collected and infused into the recipient after the recipient has completed an induction regimen involving chemotherapy and/or radiation, depending on the protocol. This procedure is called peripheral blood stem cell transplant (PBSCT). Stem cells can also be directly harvested from bone marrow cells, which are collected from repeated aspiration of bone marrow from the posterior iliac crest.⁴ This technique is most common in children, whereas in adults peripheral blood stem cells are the most common source. Overall mortality does not differ based on the source of the stem cells. It is postulated that GVHD may be more common in patients undergoing PBSCT, but the graft failure rate may be lower.⁵

The third option is umbilical cord blood (UCB) as the source of stem cells. This involves the collection of umbilical cord blood that is prepared and frozen after birth. It has a smaller volume of cells, and although fewer cells are needed when using UCB, 2 separate donors may be required for a single adult recipient. The engraftment of the stem cells is slower and infections in the post-transplant period are more common. Prior reports indicate GVHD rates may be lower.⁴ While the use of UCB is not common in adults, the incidence has doubled over the past decade, increasing from 3% to 6%.

The conditioning regimen can influence pulmonary complications. Traditionally, an ablative transplant involves high-dose chemotherapy or radiation to eradicate the recipient’s bone marrow. This regimen can lead to many complications, especially in the immediate post-transplant period. In the past 10 years, there has been increasing interest in non-myeloablative, or reduced-intensity, conditioning transplants.⁶ These “mini transplants” involve smaller doses of chemotherapy or radiation, which do not totally eradicate the bone marrow; after the transplant a degree of chimerism develops where the donor and recipient stem cells coexist. The medications in the preparative regimen also should be considered because they can affect pulmonary complications after transplant. Certain chemotherapeutic agents such as carmustine, bleomycin, and many others can lead to acute and chronic presentations of pulmonary diseases such as hypersensitivity pneumonitis, pulmonary fibrosis, acute respiratory distress syndrome, and abnormal pulmonary function testing.

After the HSCT, GVHD can develop in more than 50% of allogeneic recipients.³ The incidence of GVHD has been reported to be increasing over the past 12 years.It is divided into acute GVHD (which traditionally happens in the first 100 days after transplant) and chronic GVHD (after day 100). This calendar-day–based system has been augmented based on a 2006 National Institutes of Health working group report emphasizing the importance of organ-specific features of chronic GVHD in the clinical presentation of GVHD.⁷ Histologic changes in chronic organ GVHD tend to include more fibrotic features, whereas in acute GVHD more inflammatory changes are seen. The NIH working group report also stressed the importance of obtaining a biopsy specimen for histopathologic review and interdisciplinary collaboration to arrive at a consensus diagnosis, and noted the limitations of using histologic changes as the sole determinant of a “gold standard” diagnosis.⁷ GVHD can directly predispose patients to pulmonary GVHD and indirectly predispose them to infectious complications because the mainstay of therapy for GVHD is increased immunosuppression.

Pretransplant Evaluation

Case Patient 1

A 56-year-old man is diagnosed with acute myeloid leukemia (AML) after presenting with signs and symptoms consistent with pancytopenia. He has a past medical history of chronic sinus congestion, arthritis, depression, chronic pain, and carpal tunnel surgery. He is employed as an oilfield worker and has a 40-pack-year smoking history, but he recently cut back to half a pack per day. He is being evaluated for allogeneic transplant with his brother as the donor and the planned conditioning regimen is total body irradiation (TBI), thiotepa, cyclophosphamide, and antithymocyte globulin with T-cell depletion. Routine pretransplant pulmonary function testing (PFT) reveals a restrictive pattern and he is sent for pretransplant pulmonary evaluation.

Physical exam reveals a chronically ill appearing man. He is afebrile, the respiratory rate is 16 breaths/min, blood pressure is 145/88 mm Hg, heart rate is 92 beats/min, and oxygen saturation is 95%. He is in no distress. Auscultation of the chest reveals slightly diminished breath sounds bilaterally but is clear and without wheezes, rhonchi, or rales. Heart exam shows regular rate and rhythm without murmurs, rubs, or gallops. Extremities reveal no edema or rashes. Otherwise, the remainder of the exam is normal. The patient’s PFT results are shown in Table 2.

• What aspects of this patient’s history put him at risk for pulmonary complications after transplantation?

Risk Factors for Pulmonary Complications

Predicting who is at risk for pulmonary complications is difficult. Complications are generally divided into infectious and noninfectious categories. Regardless of category, allogeneic HSCT recipients are at increased risk compared with autologous recipients, but even in autologous transplants, more than 25% of patients will develop pulmonary complications in the first year.⁸ Prior to transplant, patients undergo full PFT. Early on, many studies attempted to show relationships between various factors and post-transplant pulmonary complications. Factors that were implicated were forced expiratory volume in 1 second (FEV₁), diffusing capacity of the lung for carbon monoxide (Dlco), total lung capacity (TLC), GVHD prophylaxis, TBI, and FEV₁/forced vital capacity (FEV₁/FVC) ratio.^9-15 Generally, poor baseline pulmonary functional status has been shown to correlate with higher risk for pulmonary complications. The most widely accepted pre-transplant PFT values examined for determining risk for developing pulmonary complications are FEV₁ and Dlco.

Another sometimes overlooked risk before transplantation is restrictive lung disease. One study showed a twofold increase in respiratory failure and mortality if there was pretransplant restriction based on TLC < 80%.¹⁶

An interesting study by one group in pretransplant evaluation found decreased muscle strength by maximal inspiratory muscle strength (PImax), maximal expiratory muscle strength (PEmax), dominant hand grip strength, and 6-minute walk test (6MWT) distance prior to allogeneic transplant, but did not find a relationship between these variables and mortality.¹⁷ While this study had a small sample size, these findings likely deserve continued investigation.¹⁸

• What methods are used to calculate risk for complications?

Risk Scoring Systems

Several pretransplantation risk scores have been developed. In a study that looked at more than 2500 allogeneic transplants, Parimon et al showed that risk of mortality and respiratory failure could be estimated prior to transplant using a scoring system—the Lung Function Score (LFS)—that combines the FEV₁ and Dlco.¹⁹ They assigned a score to the FEV₁ and Dlco based on the percentage of predicted values on PFT. Values greater than 80% were assigned 1 point, values 70% to 80% 2 points, 60% to 70% 3 points, and less than 60% 4 points. Combining the values for the FEV₁ and Dlco provides the LFS. A normal score is 2 (1 point each for FEV₁ and Dlco values > 80%) and is category I. A score of 3–4 is mildly decreased, category II; a score of 5–6 is moderately decreased, category III; and 7–8 is severely decreased, category IV. The hazard ratios (HR) for acute respiratory failure after transplant were 1.4, 2.2, and 3.1 for categories II, III, and IV, respectively. The HRs for mortality were 1.2, 2.2, and 2.7 for the same categories.¹⁹ This LFS has been used post-transplantation as well to categorize pulmonary GVHD.²⁰

The Pretransplantation Assessment of Mortality score, initially developed in 2006, predicts mortality within the first 2 years after HSCT based on 8 clinical factors: disease risk, age at transplant, donor type, conditioning regimen, and markers of organ function (percentage of predicted FEV₁, percentage of predicted Dlco, serum creatinine level, serum alanine aminotransferase level). Given the increased use of reduced-intensity conditioning regimens, the authors reevaluated the PAM score and following this analysis, creatinine, percent predicted Dlco, and liver function tests were found to no longer be statistically significant and were removed from the PAM score in 2015.^21,22 Another widely used score is the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI),²³ which predicts mortality following allogeneic stem cell transplantation. The HCT-CI also uses the FEV₁ and the Dlco as the 2 objective measures of pulmonary function.²³ While these pulmonary tests help with risk stratification, they are not perfect and it is not advised to use an isolated low Dlco to exclude individuals from transplant.²⁴ Recently, Coffey et al looked at the practice of correcting Dlco for hemoglobin by the Cotes method as suggested by the American Thoracic Society (ATS) versus the Dinakara method that was used in the HCT-CI.²⁵ In this study, the use of the Cotes method resulted in an elevated HCT-CI in 45% of patients, and in 33% it resulted in higher mortality risk predictions. Since the HCT-CI is validated using the Dinakara method, that method should be used in the HCT-CI calculations.²⁵

• What other preoperative testing or interventions should be considered in this patient?

Since there is a high risk of infectious complications after transplant, the question of whether pretransplantation patients should undergo screening imaging may arise. There is no evidence that routine chest computed tomography (CT) reduces the risk of infectious complications after transplantation.²⁶ An area that may be insufficiently addressed in the pretransplantation evaluation is smoking cessation counseling.²⁷ Studies have shown an elevated risk of mortality in smokers.^28-30 Others have found a higher incidence of respiratory failure but not an increased mortality.³¹ Overall, with the good rates of smoking cessation that can be accomplished, smokers should be counseled to quit before transplantation.

In summary, patients should undergo full PFTs prior to transplantation to help stratify risk for pulmonary complications and mortality and to establish a clinical baseline. The LFS (using FEV₁ and Dlco) can help categorize risk of respiratory failure and mortality after transplant. Absolute cut-off values for FEV₁ and Dlco are debated, but < 40% predicted and < 30% to 40% predicted, respectively, are considered contraindications to transplant. Smoking cessation should be advised if applicable during the pretransplant visit and optimization of reversible lung conditions should be stressed. There are no formal recommendations about reducing risk of early complications, but early mobilization, incentive spirometry, and use of inhalers if there is any history of obstructive lung disease should be considered.

Case Patient 1 Conclusion

The patient undergoes transplantation due to his lack of other treatment options. Evaluation prior to transplant, however, shows that he is at high risk for pulmonary complications. He has a LFS of 7 prior to transplant (using the Dlco corrected for hemoglobin), which puts him in class IV, with a HR of 3.1 for early respiratory failure and a HR of 2.7 for mortality. Additionally, he is still smoking at the time of transplantation. He does well immediately after transplantation, but has a complicated course with worsening mixed restrictive and obstructive pulmonary function abnormality. He becomes oxygen dependent and eventually undergoes video-assisted thoracoscopic surgery (VATS), which shows both usual interstitial pneumonia and restrictive bronchiolitis with changes consistent with mild to moderate pulmonary hypertension. He dies 2 years to the month after transplantation.

Early Infectious Pulmonary Complications

Case Patient 2

A 27-year-old man with a medical history significant for AML and allogeneic HSCT presents with cough productive of a small amount of clear to white sputum, dyspnea on exertion, and fevers for 1 week. He also has mild nausea and a decrease in appetite. He underwent HSCT 2.5 months prior to admission, which was a matched unrelated bone marrow transplant with TBI and cyclophosphamide conditioning. His past medical history is significant only for exercise-induced asthma for which he takes a rescue inhaler infrequently prior to transplantation. His pretransplant PFTs showed normal spirometry with an FEV₁ of 106% of predicted and Dlco of 54% of predicted. He does not smoke. His post-transplant medical course was complicated by severe acute skin GVHD as well as diarrhea, with sigmoidoscopy showing GVHD.

Physical exam is notable for fever of 101.0°F, heart rate 80 beats/min, respiratory rate 16 breaths/ min, and blood pressure 142/78 mm Hg; an admission oxygen saturation is 93% on room air. Lungs show bibasilar crackles and the remainder of the exam is normal. Laboratory testing shows a white blood cell count of 2400 cells/μL, hemoglobin 7.6 g/dL, and platelet count 66 × 10³/μL. Creatinine is 1.0 mg/dL. Chest radiograph shows ill-defined bilateral lower-lobe infiltrates. CT scans are shown in the Figure.

• For which infectious complications is this patient most at risk?

Pneumonia

A prospective trial in the HSCT population reported a pneumonia incidence rate of 68%, and pneumonia is more common in allogeneic HSCT with prolonged immunosuppressive therapy.³² Development of pneumonia within 100 days of transplant directly correlates with nonrelapsed mortality.³³ Early detection is key, and bronchoscopy within the first 5 days of symptoms has been shown to change therapy in approximately 40% of cases but has not been shown to affect mortality.³⁴ The clinical presentation of pneumonia in the HSCT population can be variable because of the presence of neutropenia and profound immunosuppression. Traditionally accepted diagnostic criteria of fevers, sputum production, and new infiltrates should be used with caution, and an appropriately high index of suspicion should be maintained. Progression to respiratory failure, regardless of causative organism of infection, portends a poor prognosis, with mortality rates estimated at 70% to 90%.^35,36 Several transplant-specific factors may affect early infections. For instance, UCB transplants have been found to have a higher incidence of invasive aspergillosis and cytomegalovirus (CMV) infections but without higher mortality attributed to the infections.³⁷

Bacterial Pneumonia

Bacterial pneumonia accounts for 20% to 50% of pneumonia cases in HSCT recipients.³⁸ Gram-negative organisms, specifically Pseudomonas aeruginosa and Escherichia coli, were reported to be the most common pathologic bacteria in recent prospective trials, whereas previous retrospective trials showed that common community-acquired organisms were the most common cause of pneumonia in HSCT recipients.^32,39 This underscores the importance of being aware of the clinical prevalence of microorganisms and local antibiograms, along with associated institutional susceptibility profiles. Initiation of immediate empiric broad-spectrum antibiotics is essential when bacterial pneumonia is suspected.

Viral Pneumonia

The prevalence of viral pneumonia in stem cell transplant recipients is estimated at 28%,³² with most cases being caused by community viral pathogens such as rhinovirus, respiratory syncytial virus (RSV), influenza A and B, and parainfluenza.³⁹ The prevention, prophylaxis, and early treatment of viral pneumonias, specifically CMV infection, have decreased the mortality associated with early pneumonia after HSCT. Co-infection with bacterial organisms must be considered and has been associated with increased mortality in the intensive care unit setting.⁴⁰

Supportive treatment with rhinovirus infection is sufficient as the disease is usually self-limited in immunocompromised patients. In contrast, infection with RSV in the lower respiratory tract is associated with increased mortality in prior reports, and recent studies suggest that further exploration of prophylaxis strategies is warranted.⁴¹ Treatment with ribavirin remains the backbone of therapy, but drug toxicity continues to limit its use. The addition of immunomodulators such as RSV immune globulin or palivizumab to ribavirin remains controversial, but a retrospective review suggests that early treatment may prevent progression to lower respiratory tract infection and lead to improved mortality.⁴² Infection with influenza A/B must be considered during influenza season. Treatment with oseltamivir may shorten the duration of disease when influenza A/B or parainfluenza are detected. Reactivation of latent herpes simplex virus during the pre-engraftment phase should also be considered. Treatment is similar to that in nonimmunocompromised hosts. When CMV pneumonia is suspected, careful history regarding compliance with prophylactic antivirals and CMV status of both the recipient and donor are key. A presumptive diagnosis can be made with the presence of appropriate clinical scenario, supportive radiographic images showing areas of ground-glass opacification or consolidation, and positive CMV polymerase chain reaction (PCR) assay. Visualization of inclusion bodies on lung biopsy tissue remains the gold standard for diagnosis. Treatment consists of CMV immunoglobulin and ganciclovir.

Fungal Pneumonia

Early fungal pneumonias have been associated with increased mortality in the HSCT population.⁴³ Clinical suspicion should remain high and compliance with antifungal prophylaxis should be questioned thoroughly. Invasive aspergillosis (IA) remains the most common fungal infection. A bimodal distribution of onset of infection peaking on day 16 and again on day 96 has been described in the literature.⁴⁴ Patients often present with classic pneumonia symptoms, but these may be accompanied by hemoptysis. Proven IA diagnosis requires visualization of fungal forms from biopsy or needle aspiration or a positive culture obtained in a sterile fashion.⁴⁵ Most clinical data comes from experience with probable and possible diagnosis of IA. Bronchoalveolar lavage with testing with Aspergillus galactomannan assay has been shown to be clinically useful in establishing the clinical diagnosis in the HSCT population.⁴⁶ Classic air-crescent findings on chest CT are helpful in establishing a possible diagnosis, but retrospective analysis reveals CT findings such as focal infiltrates and pulmonary nodular patterns are more common.⁴⁷ First-line treatment with voriconazole has been shown to decrease short-term mortality attributable to IA but has not had an effect on long-term, all-cause mortality.⁴⁸ Surgical resection is reserved for patients with refractory disease or patients presenting with massive hemoptysis.

Mucormycosis is an emerging disease with ever increasing prevalence in the HSCT population, reflecting the improved prophylaxis and treatment of IA. Initial clinical presentation is similar to IA, most commonly affecting the lung, although craniofacial involvement is classic for mucormycosis, especially in HSCT patients with diabetes.⁴⁹Mucor infections can present with massive hemoptysis due to tissue invasion and disregard for tissue and fascial planes. Diagnosis of mucormycosis is associated with as much as a six-fold increase in risk for death. Diagnosis requires identification of the organism by examination or culture and biopsy is often necessary.^50,51 Amphotericin B remains first-line therapy as mucormycosis is resistant to azole antifungals, with higher doses recommended for cerebral involvement.⁵²

Candida pulmonary infections during the early HSCT period are becoming increasingly rare due to widespread use of fluconazole prophylaxis and early treatment of mucosal involvement during neutropenia. Endemic fungal infections such as blastomycosis, coccidioidomycosis, and histoplasmosis should be considered in patients inhabiting specific geographic areas or with recent travel to these areas.

• What test should be performed to evaluate for infectious causes of pneumonia?

Role of Flexible Fiberoptic Bronchoscopy

The utility of flexible fiberoptic bronchoscopy (FOB) in immune-compromised patients for the evaluation of pulmonary infiltrates is a frequently debated topic. Current studies suggest a diagnosis can be made in approximately 80% of cases in the immune-compromised population.^32,53 Noninvasive testing such as urine and serum antigens, sputum cultures, Aspergillus galactomannan assays, viral nasal swabs, and PCR studies often lead to a diagnosis in appropriate clinical scenarios. Conservative management would dictate the use of noninvasive testing whenever possible, and randomized controlled trials have shown noninvasive testing to be noninferior to FOB in preventing need for mechanical ventilation, with no difference in overall mortality.⁵⁴ FOB has been shown to be most useful in establishing a diagnosis when an infectious etiology is suspected.⁵⁵ In multivariate analysis, a delay in the identification of the etiology of pulmonary infiltrate was associated with increased mortality.⁵⁶ Additionally, early FOB was found to be superior to late FOB in revealing a diagnosis. ^32,57 Despite its ability to detect the cause of pulmonary disease, direct antibiotic therapy, and possibly change therapy, FOB with diagnostic maneuvers has not been shown to affect mortality.⁵⁸ In a large case series, FOB with bronchoalveolar lavage (BAL) revealed a diagnosis in approximately 30% to 50% of cases. The addition of transbronchial biopsy did not improve diagnostic utility.⁵⁸ More recent studies have confirmed that the addition of transbronchial biopsy does not add to diagnostic yield and is associated with increased adverse events.⁵⁹ The appropriate use of advanced techniques such as endobronchial ultrasound–guided transbronchial needle aspirations, endobronchial biopsy, and CT-guided navigational bronchoscopy has not been established and should be considered on a case-by-case basis. In summary, routine early BAL is the diagnostic test of choice, especially when infectious pulmonary complications are suspected.

Contraindications for FOB in this population mirror those in the general population. These include acute severe hypoxemic respiratory failure, myocardial ischemia or acute coronary syndrome within 2 weeks of procedure, severe thrombocytopenia, and inability to provide or obtain informed consent from patient or health care power of attorney. Coagulopathy and thrombocytopenia are common comorbid conditions in the HSCT population. A platelet count of < 20 × 10³/µL has generally been used as a cut-off for routine FOB with BAL.⁶⁰ Risks of the procedures should be discussed clearly with the patient, but simple FOB for airway evaluation and BAL is generally well tolerated even under these conditions.

Early Nonifectious Pulmonary Complications

Case Patient 2 Continued

Bronchoscopy with BAL performed the day after admission is unremarkable and stains and cultures are negative for viral, bacterial, and fungal organisms. The patient is initially started on broad-spectrum antibiotics, but his oxygenation continues to worsen to the point that he is placed on noninvasive positive pressure ventilation. He is started empirically on amphotericin B and eventually is intubated. VATS lung biopsy is ultimately performed and pathology is consistent with diffuse alveolar damage.

• Based on these biopsy findings, what is the diagnosis?

Based on the pathology consistent with diffuse alveolar damage, a diagnosis of idiopathic pneumonia syndrome (IPS) is made.

• What noninfectious pulmonary complications occur in the early post-transplant period?

The overall incidence of noninfectious pulmonary complications after HSCT is generally estimated at 20% to 30%.³² Acute pulmonary edema is a common very early noninfectious pulmonary complication and clinically the most straightforward to treat. Three distinct clinical syndromes—peri-engraftment respiratory distress syndrome (PERDS), diffuse alveolar hemorrhage (DAH), and IPS—comprise the remainder of the pertinent early noninfectious complications. Clinical presentation differs based upon the disease entity. Recent studies have evaluated the role of angiotensin-converting enzyme polymorphisms as a predictive marker for risk of developing early noninfectious pulmonary complications.⁶¹

Peri-Engraftment Respiratory Distress Syndrome

PERDS is a clinical syndrome comprising the cardinal features of erythematous rash and fever along with noncardiogenic pulmonary infiltrates and hypoxemia that occur in the peri-engraftment period, defined as recovery of absolute neutrophil count to > 500/μL on 2 consecutive days.⁶² PERDS occurs in the autologous HSCT population and may be a clinical correlate to early GVHD in the allogeneic HSCT population. It is hypothesized that the pathophysiology underlying PERDS is an autoimmune-related capillary leak caused by pro-inflammatory cytokine release.⁶³ Treatment remains anecdotal and currently consists of supportive care and high-dose corticosteroids. Some have favored limiting the use of gCSF given its role in stimulating rapid white blood cell recovery.³³ Prognosis is favorable, but progression to fulminant respiratory failure requiring mechanical ventilation portends a poor prognosis.

Diffuse Alveolar Hemorrhage

DAH is clinical syndrome consisting of diffuse alveolar infiltrates on pulmonary imaging combined with progressively bloodier return per aliquot during BAL in 3 different subsegments or more than 20% hemosiderin-laden macrophages on BAL fluid evaluation. Classically, DAH is defined in the absence of pulmonary infection or cardiac dysfunction. The pathophysiology is thought to be related to inflammation of pulmonary vasculature within the alveolar walls leading to alveolitis. Although no prospective trials exist, early use of high-dose corticosteroid therapy is thought to improve outcomes;^64,65 a recent study, however, showed low-dose steroids may be associated with the lowest mortality.⁶⁶ Mortality is directly linked to the presence of superimposed infection, need for mechanical ventilation, late onset, and development of multiorgan failure.⁶⁷

Idiopathic Pneumonia Syndrome

IPS is a complex clinical syndrome whose pathology is felt to stem from a variety of possible lung insults such as direct myeloablative drug toxicity, occult pulmonary infection, or cytokine-driven inflammation. The ATS published an article further subcategorizing IPS as different clinical entities based upon whether the primary insult involves the vascular endothelium, interstitial tissue, and airway tissue, truly idiopathic, or unclassified.⁶⁸ In clinical practice, IPS is defined as widespread alveolar injury in the absence of evidence of renal failure, heart failure, and excessive fluid resuscitation. In addition, negative testing for a variety of bacterial, viral, and fungal causes is also necessary.⁶⁹ Clinical syndromes included within the IPS definition are ARDS, acute interstitial pneumonia, DAH, cryptogenic organizing pneumonia, and BOS.⁷⁰ Risk factors for developing IPS include TBI, older age of recipient, acute GVHD, and underlying diagnosis of AML or myelodysplastic syndrome.¹² In addition, it has been shown that risk for developing IPS is lower in patients undergoing allogeneic HSCT who receive non-myeloablative conditioning regimens.⁷¹ The pathologic finding in IPS is diffuse alveolar damage. A 2006 study in which investigators reviewed BAL samples from patients with IPS found that 3% of the patients had PCR evidence of human metapneumovirus infection, and a study in 2015 found PCR evidence of infection in 53% of BAL samples from patients diagnosed with IPS.^72,73 This fuels the debate on whether IPS is truly an infection-driven process where the source of infection, pulmonary or otherwise, simply escapes detection. Various surfactant proteins, which play a role in decreasing surface tension within the alveolar interface and function as mediators within the innate immunity of the lung, have been studied in regard to development of IPS. Small retrospective studies have shown a trend toward lower pre-transplant serum protein surfactant D and the development of IPS.⁷⁴

The diagnosis of IPS does not require pathologic diagnosis in most circumstances. The correct clinical findings in association with a negative infectious workup lead to a presumptive diagnosis of IPS. The extent of the infectious workup that must be completed to adequately rule out infection is often a difficult clinical question. Recent recommendations include BAL fluid evaluation for routine bacterial cultures, appropriate viral culture, and consideration of PCR testing to evaluate for Mycoplasma, Chlamydia, and Aspergillus antigens.⁷⁵ Transbronchial biopsy continues to appear in recommendations, but is not routinely performed and should be completed as the patient’s clinical status permits.^8,68 Table 3 reviews basic features of early noninfectious pulmonary complications.

• What treatment should be offered to the patient with diffuse alveolar damage on biopsy?

Treatment consists of supportive care and empiric broad-spectrum antibiotics with consideration of high-dose corticosteroids. Based upon early studies in murine models implicating TNF, pilot studies were performed evaluating etanercept as a possible safe and effective addition to high-dose systemic corticosteroids.⁷⁷ Although these results were promising, data from a truncated randomized control clinical trial failed to show improvement in patient response in the adult population.⁷⁶ More recent data from the same author suggests that pediatric populations with IPS are, however, responsive to etanercept and high-dose corticosteroid therapy.⁷⁸ When IPS develops as a late complication, treatment with high-dose corticosteroids (2 mg/kg/day) and etanercept (0.4 mg/kg twice weekly) has been shown to improve 2-year survival.⁷⁹

Case Patient 2 Conclusion

The patient is started on steroids and makes a speedy recovery. He is successfully extubated 5 days later.

Conclusion

Careful pretransplant evaluation, including a full set of pulmonary function tests, can help predict a patient’s risk for pulmonary complications after transplant, allowing risk factor modification strategies to be implemented prior to transplant, including smoking cessation. It also helps identify patients at high risk for complications who will require closer monitoring after transplantation. Early posttransplant complications include infectious and noninfectious entities. Bacterial, viral, and fungal pneumonias are in the differential of infectious pneumonia, and bronchoscopy can be helpful in establishing a diagnosis. A common, important noninfectious cause of early pulmonary complications is IPS, which is treated with steroids and sometimes anti-TNF therapy.

Hematopoietic stem cell transplantation (HSCT) is widely used in the economically developed world to treat a variety of hematologic malignancies as well as nonmalignant diseases and solid tumors. An estimated 17,900 HSCTs were performed in 2011, and survival rates continue to increase.¹ Pulmonary complications post HSCT are common, with rates ranging from 40% to 60%, and are associated with increased morbidity and mortality.²

Clinical diagnosis of pulmonary complications in the HSCT population has been aided by a previously well-defined chronology of the most common diseases.³ Historically, early pulmonary complications were defined as pulmonary complications occurring within 100 days of HSCT (corresponding to the acute graft-versus-host disease [GVHD] period). Late pulmonary complications are those that occur thereafter. This timeline, however, is now more variable given the increasing indications for HSCT, the use of reduced-intensity conditioning strategies, and varied individual immune reconstitution. This article discusses the management of early post-HSCT pulmonary complications; late post-HSCT pulmonary complications will be discussed in a separate follow-up article.

Transplant Basics

The development of pulmonary complications is affected by many factors associated with the transplant. Autologous transplantation involves the collection of a patient’s own stem cells, appropriate storage and processing, and re-implantation after induction therapy. During induction therapy, the patient undergoes high-dose chemotherapy or radiation therapy that ablates the bone marrow. The stem cells are then transfused back into the patient to repopulate the bone marrow. Allogeneic transplants involve the collection of stem cells from a donor. Donors are matched as closely as possible to the recipient’s histocompatibility antigen (HLA) haplotypes to prevent graft failure and rejection. The donor can be related or unrelated to the recipient. If there is not a possibility of a related match (from a sibling), then a national search is undertaken to look for a match through the National Marrow Donor Program. There are fewer transplant reactions and occurrences of GVHD if the major HLAs of the donor and recipient match. Table 1 reviews basic definitions pertaining to HSCT.

How the cells for transplantation are obtained is also an important factor in the rate of complications. There are 3 main sources: peripheral blood, bone marrow, and umbilical cord. Peripheral stem cell harvesting involves exposing the donor to granulocyte-colony stimulating factor (gCSF), which increases peripheral circulation of stem cells. These cells are then collected and infused into the recipient after the recipient has completed an induction regimen involving chemotherapy and/or radiation, depending on the protocol. This procedure is called peripheral blood stem cell transplant (PBSCT). Stem cells can also be directly harvested from bone marrow cells, which are collected from repeated aspiration of bone marrow from the posterior iliac crest.⁴ This technique is most common in children, whereas in adults peripheral blood stem cells are the most common source. Overall mortality does not differ based on the source of the stem cells. It is postulated that GVHD may be more common in patients undergoing PBSCT, but the graft failure rate may be lower.⁵

The third option is umbilical cord blood (UCB) as the source of stem cells. This involves the collection of umbilical cord blood that is prepared and frozen after birth. It has a smaller volume of cells, and although fewer cells are needed when using UCB, 2 separate donors may be required for a single adult recipient. The engraftment of the stem cells is slower and infections in the post-transplant period are more common. Prior reports indicate GVHD rates may be lower.⁴ While the use of UCB is not common in adults, the incidence has doubled over the past decade, increasing from 3% to 6%.

The conditioning regimen can influence pulmonary complications. Traditionally, an ablative transplant involves high-dose chemotherapy or radiation to eradicate the recipient’s bone marrow. This regimen can lead to many complications, especially in the immediate post-transplant period. In the past 10 years, there has been increasing interest in non-myeloablative, or reduced-intensity, conditioning transplants.⁶ These “mini transplants” involve smaller doses of chemotherapy or radiation, which do not totally eradicate the bone marrow; after the transplant a degree of chimerism develops where the donor and recipient stem cells coexist. The medications in the preparative regimen also should be considered because they can affect pulmonary complications after transplant. Certain chemotherapeutic agents such as carmustine, bleomycin, and many others can lead to acute and chronic presentations of pulmonary diseases such as hypersensitivity pneumonitis, pulmonary fibrosis, acute respiratory distress syndrome, and abnormal pulmonary function testing.

After the HSCT, GVHD can develop in more than 50% of allogeneic recipients.³ The incidence of GVHD has been reported to be increasing over the past 12 years.It is divided into acute GVHD (which traditionally happens in the first 100 days after transplant) and chronic GVHD (after day 100). This calendar-day–based system has been augmented based on a 2006 National Institutes of Health working group report emphasizing the importance of organ-specific features of chronic GVHD in the clinical presentation of GVHD.⁷ Histologic changes in chronic organ GVHD tend to include more fibrotic features, whereas in acute GVHD more inflammatory changes are seen. The NIH working group report also stressed the importance of obtaining a biopsy specimen for histopathologic review and interdisciplinary collaboration to arrive at a consensus diagnosis, and noted the limitations of using histologic changes as the sole determinant of a “gold standard” diagnosis.⁷ GVHD can directly predispose patients to pulmonary GVHD and indirectly predispose them to infectious complications because the mainstay of therapy for GVHD is increased immunosuppression.

Pretransplant Evaluation

Case Patient 1

A 56-year-old man is diagnosed with acute myeloid leukemia (AML) after presenting with signs and symptoms consistent with pancytopenia. He has a past medical history of chronic sinus congestion, arthritis, depression, chronic pain, and carpal tunnel surgery. He is employed as an oilfield worker and has a 40-pack-year smoking history, but he recently cut back to half a pack per day. He is being evaluated for allogeneic transplant with his brother as the donor and the planned conditioning regimen is total body irradiation (TBI), thiotepa, cyclophosphamide, and antithymocyte globulin with T-cell depletion. Routine pretransplant pulmonary function testing (PFT) reveals a restrictive pattern and he is sent for pretransplant pulmonary evaluation.

Physical exam reveals a chronically ill appearing man. He is afebrile, the respiratory rate is 16 breaths/min, blood pressure is 145/88 mm Hg, heart rate is 92 beats/min, and oxygen saturation is 95%. He is in no distress. Auscultation of the chest reveals slightly diminished breath sounds bilaterally but is clear and without wheezes, rhonchi, or rales. Heart exam shows regular rate and rhythm without murmurs, rubs, or gallops. Extremities reveal no edema or rashes. Otherwise, the remainder of the exam is normal. The patient’s PFT results are shown in Table 2.

• What aspects of this patient’s history put him at risk for pulmonary complications after transplantation?

Risk Factors for Pulmonary Complications

Predicting who is at risk for pulmonary complications is difficult. Complications are generally divided into infectious and noninfectious categories. Regardless of category, allogeneic HSCT recipients are at increased risk compared with autologous recipients, but even in autologous transplants, more than 25% of patients will develop pulmonary complications in the first year.⁸ Prior to transplant, patients undergo full PFT. Early on, many studies attempted to show relationships between various factors and post-transplant pulmonary complications. Factors that were implicated were forced expiratory volume in 1 second (FEV₁), diffusing capacity of the lung for carbon monoxide (Dlco), total lung capacity (TLC), GVHD prophylaxis, TBI, and FEV₁/forced vital capacity (FEV₁/FVC) ratio.^9-15 Generally, poor baseline pulmonary functional status has been shown to correlate with higher risk for pulmonary complications. The most widely accepted pre-transplant PFT values examined for determining risk for developing pulmonary complications are FEV₁ and Dlco.

Another sometimes overlooked risk before transplantation is restrictive lung disease. One study showed a twofold increase in respiratory failure and mortality if there was pretransplant restriction based on TLC < 80%.¹⁶

An interesting study by one group in pretransplant evaluation found decreased muscle strength by maximal inspiratory muscle strength (PImax), maximal expiratory muscle strength (PEmax), dominant hand grip strength, and 6-minute walk test (6MWT) distance prior to allogeneic transplant, but did not find a relationship between these variables and mortality.¹⁷ While this study had a small sample size, these findings likely deserve continued investigation.¹⁸

• What methods are used to calculate risk for complications?

Risk Scoring Systems

Several pretransplantation risk scores have been developed. In a study that looked at more than 2500 allogeneic transplants, Parimon et al showed that risk of mortality and respiratory failure could be estimated prior to transplant using a scoring system—the Lung Function Score (LFS)—that combines the FEV₁ and Dlco.¹⁹ They assigned a score to the FEV₁ and Dlco based on the percentage of predicted values on PFT. Values greater than 80% were assigned 1 point, values 70% to 80% 2 points, 60% to 70% 3 points, and less than 60% 4 points. Combining the values for the FEV₁ and Dlco provides the LFS. A normal score is 2 (1 point each for FEV₁ and Dlco values > 80%) and is category I. A score of 3–4 is mildly decreased, category II; a score of 5–6 is moderately decreased, category III; and 7–8 is severely decreased, category IV. The hazard ratios (HR) for acute respiratory failure after transplant were 1.4, 2.2, and 3.1 for categories II, III, and IV, respectively. The HRs for mortality were 1.2, 2.2, and 2.7 for the same categories.¹⁹ This LFS has been used post-transplantation as well to categorize pulmonary GVHD.²⁰

The Pretransplantation Assessment of Mortality score, initially developed in 2006, predicts mortality within the first 2 years after HSCT based on 8 clinical factors: disease risk, age at transplant, donor type, conditioning regimen, and markers of organ function (percentage of predicted FEV₁, percentage of predicted Dlco, serum creatinine level, serum alanine aminotransferase level). Given the increased use of reduced-intensity conditioning regimens, the authors reevaluated the PAM score and following this analysis, creatinine, percent predicted Dlco, and liver function tests were found to no longer be statistically significant and were removed from the PAM score in 2015.^21,22 Another widely used score is the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI),²³ which predicts mortality following allogeneic stem cell transplantation. The HCT-CI also uses the FEV₁ and the Dlco as the 2 objective measures of pulmonary function.²³ While these pulmonary tests help with risk stratification, they are not perfect and it is not advised to use an isolated low Dlco to exclude individuals from transplant.²⁴ Recently, Coffey et al looked at the practice of correcting Dlco for hemoglobin by the Cotes method as suggested by the American Thoracic Society (ATS) versus the Dinakara method that was used in the HCT-CI.²⁵ In this study, the use of the Cotes method resulted in an elevated HCT-CI in 45% of patients, and in 33% it resulted in higher mortality risk predictions. Since the HCT-CI is validated using the Dinakara method, that method should be used in the HCT-CI calculations.²⁵

• What other preoperative testing or interventions should be considered in this patient?

Since there is a high risk of infectious complications after transplant, the question of whether pretransplantation patients should undergo screening imaging may arise. There is no evidence that routine chest computed tomography (CT) reduces the risk of infectious complications after transplantation.²⁶ An area that may be insufficiently addressed in the pretransplantation evaluation is smoking cessation counseling.²⁷ Studies have shown an elevated risk of mortality in smokers.^28-30 Others have found a higher incidence of respiratory failure but not an increased mortality.³¹ Overall, with the good rates of smoking cessation that can be accomplished, smokers should be counseled to quit before transplantation.

In summary, patients should undergo full PFTs prior to transplantation to help stratify risk for pulmonary complications and mortality and to establish a clinical baseline. The LFS (using FEV₁ and Dlco) can help categorize risk of respiratory failure and mortality after transplant. Absolute cut-off values for FEV₁ and Dlco are debated, but < 40% predicted and < 30% to 40% predicted, respectively, are considered contraindications to transplant. Smoking cessation should be advised if applicable during the pretransplant visit and optimization of reversible lung conditions should be stressed. There are no formal recommendations about reducing risk of early complications, but early mobilization, incentive spirometry, and use of inhalers if there is any history of obstructive lung disease should be considered.

Case Patient 1 Conclusion

The patient undergoes transplantation due to his lack of other treatment options. Evaluation prior to transplant, however, shows that he is at high risk for pulmonary complications. He has a LFS of 7 prior to transplant (using the Dlco corrected for hemoglobin), which puts him in class IV, with a HR of 3.1 for early respiratory failure and a HR of 2.7 for mortality. Additionally, he is still smoking at the time of transplantation. He does well immediately after transplantation, but has a complicated course with worsening mixed restrictive and obstructive pulmonary function abnormality. He becomes oxygen dependent and eventually undergoes video-assisted thoracoscopic surgery (VATS), which shows both usual interstitial pneumonia and restrictive bronchiolitis with changes consistent with mild to moderate pulmonary hypertension. He dies 2 years to the month after transplantation.

Early Infectious Pulmonary Complications

Case Patient 2

A 27-year-old man with a medical history significant for AML and allogeneic HSCT presents with cough productive of a small amount of clear to white sputum, dyspnea on exertion, and fevers for 1 week. He also has mild nausea and a decrease in appetite. He underwent HSCT 2.5 months prior to admission, which was a matched unrelated bone marrow transplant with TBI and cyclophosphamide conditioning. His past medical history is significant only for exercise-induced asthma for which he takes a rescue inhaler infrequently prior to transplantation. His pretransplant PFTs showed normal spirometry with an FEV₁ of 106% of predicted and Dlco of 54% of predicted. He does not smoke. His post-transplant medical course was complicated by severe acute skin GVHD as well as diarrhea, with sigmoidoscopy showing GVHD.

Physical exam is notable for fever of 101.0°F, heart rate 80 beats/min, respiratory rate 16 breaths/ min, and blood pressure 142/78 mm Hg; an admission oxygen saturation is 93% on room air. Lungs show bibasilar crackles and the remainder of the exam is normal. Laboratory testing shows a white blood cell count of 2400 cells/μL, hemoglobin 7.6 g/dL, and platelet count 66 × 10³/μL. Creatinine is 1.0 mg/dL. Chest radiograph shows ill-defined bilateral lower-lobe infiltrates. CT scans are shown in the Figure.

• For which infectious complications is this patient most at risk?

Pneumonia

A prospective trial in the HSCT population reported a pneumonia incidence rate of 68%, and pneumonia is more common in allogeneic HSCT with prolonged immunosuppressive therapy.³² Development of pneumonia within 100 days of transplant directly correlates with nonrelapsed mortality.³³ Early detection is key, and bronchoscopy within the first 5 days of symptoms has been shown to change therapy in approximately 40% of cases but has not been shown to affect mortality.³⁴ The clinical presentation of pneumonia in the HSCT population can be variable because of the presence of neutropenia and profound immunosuppression. Traditionally accepted diagnostic criteria of fevers, sputum production, and new infiltrates should be used with caution, and an appropriately high index of suspicion should be maintained. Progression to respiratory failure, regardless of causative organism of infection, portends a poor prognosis, with mortality rates estimated at 70% to 90%.^35,36 Several transplant-specific factors may affect early infections. For instance, UCB transplants have been found to have a higher incidence of invasive aspergillosis and cytomegalovirus (CMV) infections but without higher mortality attributed to the infections.³⁷

Bacterial Pneumonia

Bacterial pneumonia accounts for 20% to 50% of pneumonia cases in HSCT recipients.³⁸ Gram-negative organisms, specifically Pseudomonas aeruginosa and Escherichia coli, were reported to be the most common pathologic bacteria in recent prospective trials, whereas previous retrospective trials showed that common community-acquired organisms were the most common cause of pneumonia in HSCT recipients.^32,39 This underscores the importance of being aware of the clinical prevalence of microorganisms and local antibiograms, along with associated institutional susceptibility profiles. Initiation of immediate empiric broad-spectrum antibiotics is essential when bacterial pneumonia is suspected.

Viral Pneumonia

The prevalence of viral pneumonia in stem cell transplant recipients is estimated at 28%,³² with most cases being caused by community viral pathogens such as rhinovirus, respiratory syncytial virus (RSV), influenza A and B, and parainfluenza.³⁹ The prevention, prophylaxis, and early treatment of viral pneumonias, specifically CMV infection, have decreased the mortality associated with early pneumonia after HSCT. Co-infection with bacterial organisms must be considered and has been associated with increased mortality in the intensive care unit setting.⁴⁰

Supportive treatment with rhinovirus infection is sufficient as the disease is usually self-limited in immunocompromised patients. In contrast, infection with RSV in the lower respiratory tract is associated with increased mortality in prior reports, and recent studies suggest that further exploration of prophylaxis strategies is warranted.⁴¹ Treatment with ribavirin remains the backbone of therapy, but drug toxicity continues to limit its use. The addition of immunomodulators such as RSV immune globulin or palivizumab to ribavirin remains controversial, but a retrospective review suggests that early treatment may prevent progression to lower respiratory tract infection and lead to improved mortality.⁴² Infection with influenza A/B must be considered during influenza season. Treatment with oseltamivir may shorten the duration of disease when influenza A/B or parainfluenza are detected. Reactivation of latent herpes simplex virus during the pre-engraftment phase should also be considered. Treatment is similar to that in nonimmunocompromised hosts. When CMV pneumonia is suspected, careful history regarding compliance with prophylactic antivirals and CMV status of both the recipient and donor are key. A presumptive diagnosis can be made with the presence of appropriate clinical scenario, supportive radiographic images showing areas of ground-glass opacification or consolidation, and positive CMV polymerase chain reaction (PCR) assay. Visualization of inclusion bodies on lung biopsy tissue remains the gold standard for diagnosis. Treatment consists of CMV immunoglobulin and ganciclovir.

Fungal Pneumonia

Early fungal pneumonias have been associated with increased mortality in the HSCT population.⁴³ Clinical suspicion should remain high and compliance with antifungal prophylaxis should be questioned thoroughly. Invasive aspergillosis (IA) remains the most common fungal infection. A bimodal distribution of onset of infection peaking on day 16 and again on day 96 has been described in the literature.⁴⁴ Patients often present with classic pneumonia symptoms, but these may be accompanied by hemoptysis. Proven IA diagnosis requires visualization of fungal forms from biopsy or needle aspiration or a positive culture obtained in a sterile fashion.⁴⁵ Most clinical data comes from experience with probable and possible diagnosis of IA. Bronchoalveolar lavage with testing with Aspergillus galactomannan assay has been shown to be clinically useful in establishing the clinical diagnosis in the HSCT population.⁴⁶ Classic air-crescent findings on chest CT are helpful in establishing a possible diagnosis, but retrospective analysis reveals CT findings such as focal infiltrates and pulmonary nodular patterns are more common.⁴⁷ First-line treatment with voriconazole has been shown to decrease short-term mortality attributable to IA but has not had an effect on long-term, all-cause mortality.⁴⁸ Surgical resection is reserved for patients with refractory disease or patients presenting with massive hemoptysis.

Mucormycosis is an emerging disease with ever increasing prevalence in the HSCT population, reflecting the improved prophylaxis and treatment of IA. Initial clinical presentation is similar to IA, most commonly affecting the lung, although craniofacial involvement is classic for mucormycosis, especially in HSCT patients with diabetes.⁴⁹Mucor infections can present with massive hemoptysis due to tissue invasion and disregard for tissue and fascial planes. Diagnosis of mucormycosis is associated with as much as a six-fold increase in risk for death. Diagnosis requires identification of the organism by examination or culture and biopsy is often necessary.^50,51 Amphotericin B remains first-line therapy as mucormycosis is resistant to azole antifungals, with higher doses recommended for cerebral involvement.⁵²

Candida pulmonary infections during the early HSCT period are becoming increasingly rare due to widespread use of fluconazole prophylaxis and early treatment of mucosal involvement during neutropenia. Endemic fungal infections such as blastomycosis, coccidioidomycosis, and histoplasmosis should be considered in patients inhabiting specific geographic areas or with recent travel to these areas.

• What test should be performed to evaluate for infectious causes of pneumonia?

Role of Flexible Fiberoptic Bronchoscopy

The utility of flexible fiberoptic bronchoscopy (FOB) in immune-compromised patients for the evaluation of pulmonary infiltrates is a frequently debated topic. Current studies suggest a diagnosis can be made in approximately 80% of cases in the immune-compromised population.^32,53 Noninvasive testing such as urine and serum antigens, sputum cultures, Aspergillus galactomannan assays, viral nasal swabs, and PCR studies often lead to a diagnosis in appropriate clinical scenarios. Conservative management would dictate the use of noninvasive testing whenever possible, and randomized controlled trials have shown noninvasive testing to be noninferior to FOB in preventing need for mechanical ventilation, with no difference in overall mortality.⁵⁴ FOB has been shown to be most useful in establishing a diagnosis when an infectious etiology is suspected.⁵⁵ In multivariate analysis, a delay in the identification of the etiology of pulmonary infiltrate was associated with increased mortality.⁵⁶ Additionally, early FOB was found to be superior to late FOB in revealing a diagnosis. ^32,57 Despite its ability to detect the cause of pulmonary disease, direct antibiotic therapy, and possibly change therapy, FOB with diagnostic maneuvers has not been shown to affect mortality.⁵⁸ In a large case series, FOB with bronchoalveolar lavage (BAL) revealed a diagnosis in approximately 30% to 50% of cases. The addition of transbronchial biopsy did not improve diagnostic utility.⁵⁸ More recent studies have confirmed that the addition of transbronchial biopsy does not add to diagnostic yield and is associated with increased adverse events.⁵⁹ The appropriate use of advanced techniques such as endobronchial ultrasound–guided transbronchial needle aspirations, endobronchial biopsy, and CT-guided navigational bronchoscopy has not been established and should be considered on a case-by-case basis. In summary, routine early BAL is the diagnostic test of choice, especially when infectious pulmonary complications are suspected.

Contraindications for FOB in this population mirror those in the general population. These include acute severe hypoxemic respiratory failure, myocardial ischemia or acute coronary syndrome within 2 weeks of procedure, severe thrombocytopenia, and inability to provide or obtain informed consent from patient or health care power of attorney. Coagulopathy and thrombocytopenia are common comorbid conditions in the HSCT population. A platelet count of < 20 × 10³/µL has generally been used as a cut-off for routine FOB with BAL.⁶⁰ Risks of the procedures should be discussed clearly with the patient, but simple FOB for airway evaluation and BAL is generally well tolerated even under these conditions.

Early Nonifectious Pulmonary Complications

Case Patient 2 Continued

Bronchoscopy with BAL performed the day after admission is unremarkable and stains and cultures are negative for viral, bacterial, and fungal organisms. The patient is initially started on broad-spectrum antibiotics, but his oxygenation continues to worsen to the point that he is placed on noninvasive positive pressure ventilation. He is started empirically on amphotericin B and eventually is intubated. VATS lung biopsy is ultimately performed and pathology is consistent with diffuse alveolar damage.

• Based on these biopsy findings, what is the diagnosis?

Based on the pathology consistent with diffuse alveolar damage, a diagnosis of idiopathic pneumonia syndrome (IPS) is made.

• What noninfectious pulmonary complications occur in the early post-transplant period?

The overall incidence of noninfectious pulmonary complications after HSCT is generally estimated at 20% to 30%.³² Acute pulmonary edema is a common very early noninfectious pulmonary complication and clinically the most straightforward to treat. Three distinct clinical syndromes—peri-engraftment respiratory distress syndrome (PERDS), diffuse alveolar hemorrhage (DAH), and IPS—comprise the remainder of the pertinent early noninfectious complications. Clinical presentation differs based upon the disease entity. Recent studies have evaluated the role of angiotensin-converting enzyme polymorphisms as a predictive marker for risk of developing early noninfectious pulmonary complications.⁶¹

Peri-Engraftment Respiratory Distress Syndrome

PERDS is a clinical syndrome comprising the cardinal features of erythematous rash and fever along with noncardiogenic pulmonary infiltrates and hypoxemia that occur in the peri-engraftment period, defined as recovery of absolute neutrophil count to > 500/μL on 2 consecutive days.⁶² PERDS occurs in the autologous HSCT population and may be a clinical correlate to early GVHD in the allogeneic HSCT population. It is hypothesized that the pathophysiology underlying PERDS is an autoimmune-related capillary leak caused by pro-inflammatory cytokine release.⁶³ Treatment remains anecdotal and currently consists of supportive care and high-dose corticosteroids. Some have favored limiting the use of gCSF given its role in stimulating rapid white blood cell recovery.³³ Prognosis is favorable, but progression to fulminant respiratory failure requiring mechanical ventilation portends a poor prognosis.

Diffuse Alveolar Hemorrhage

DAH is clinical syndrome consisting of diffuse alveolar infiltrates on pulmonary imaging combined with progressively bloodier return per aliquot during BAL in 3 different subsegments or more than 20% hemosiderin-laden macrophages on BAL fluid evaluation. Classically, DAH is defined in the absence of pulmonary infection or cardiac dysfunction. The pathophysiology is thought to be related to inflammation of pulmonary vasculature within the alveolar walls leading to alveolitis. Although no prospective trials exist, early use of high-dose corticosteroid therapy is thought to improve outcomes;^64,65 a recent study, however, showed low-dose steroids may be associated with the lowest mortality.⁶⁶ Mortality is directly linked to the presence of superimposed infection, need for mechanical ventilation, late onset, and development of multiorgan failure.⁶⁷

Idiopathic Pneumonia Syndrome

IPS is a complex clinical syndrome whose pathology is felt to stem from a variety of possible lung insults such as direct myeloablative drug toxicity, occult pulmonary infection, or cytokine-driven inflammation. The ATS published an article further subcategorizing IPS as different clinical entities based upon whether the primary insult involves the vascular endothelium, interstitial tissue, and airway tissue, truly idiopathic, or unclassified.⁶⁸ In clinical practice, IPS is defined as widespread alveolar injury in the absence of evidence of renal failure, heart failure, and excessive fluid resuscitation. In addition, negative testing for a variety of bacterial, viral, and fungal causes is also necessary.⁶⁹ Clinical syndromes included within the IPS definition are ARDS, acute interstitial pneumonia, DAH, cryptogenic organizing pneumonia, and BOS.⁷⁰ Risk factors for developing IPS include TBI, older age of recipient, acute GVHD, and underlying diagnosis of AML or myelodysplastic syndrome.¹² In addition, it has been shown that risk for developing IPS is lower in patients undergoing allogeneic HSCT who receive non-myeloablative conditioning regimens.⁷¹ The pathologic finding in IPS is diffuse alveolar damage. A 2006 study in which investigators reviewed BAL samples from patients with IPS found that 3% of the patients had PCR evidence of human metapneumovirus infection, and a study in 2015 found PCR evidence of infection in 53% of BAL samples from patients diagnosed with IPS.^72,73 This fuels the debate on whether IPS is truly an infection-driven process where the source of infection, pulmonary or otherwise, simply escapes detection. Various surfactant proteins, which play a role in decreasing surface tension within the alveolar interface and function as mediators within the innate immunity of the lung, have been studied in regard to development of IPS. Small retrospective studies have shown a trend toward lower pre-transplant serum protein surfactant D and the development of IPS.⁷⁴

The diagnosis of IPS does not require pathologic diagnosis in most circumstances. The correct clinical findings in association with a negative infectious workup lead to a presumptive diagnosis of IPS. The extent of the infectious workup that must be completed to adequately rule out infection is often a difficult clinical question. Recent recommendations include BAL fluid evaluation for routine bacterial cultures, appropriate viral culture, and consideration of PCR testing to evaluate for Mycoplasma, Chlamydia, and Aspergillus antigens.⁷⁵ Transbronchial biopsy continues to appear in recommendations, but is not routinely performed and should be completed as the patient’s clinical status permits.^8,68 Table 3 reviews basic features of early noninfectious pulmonary complications.

• What treatment should be offered to the patient with diffuse alveolar damage on biopsy?

Treatment consists of supportive care and empiric broad-spectrum antibiotics with consideration of high-dose corticosteroids. Based upon early studies in murine models implicating TNF, pilot studies were performed evaluating etanercept as a possible safe and effective addition to high-dose systemic corticosteroids.⁷⁷ Although these results were promising, data from a truncated randomized control clinical trial failed to show improvement in patient response in the adult population.⁷⁶ More recent data from the same author suggests that pediatric populations with IPS are, however, responsive to etanercept and high-dose corticosteroid therapy.⁷⁸ When IPS develops as a late complication, treatment with high-dose corticosteroids (2 mg/kg/day) and etanercept (0.4 mg/kg twice weekly) has been shown to improve 2-year survival.⁷⁹

Case Patient 2 Conclusion

The patient is started on steroids and makes a speedy recovery. He is successfully extubated 5 days later.

Conclusion

Careful pretransplant evaluation, including a full set of pulmonary function tests, can help predict a patient’s risk for pulmonary complications after transplant, allowing risk factor modification strategies to be implemented prior to transplant, including smoking cessation. It also helps identify patients at high risk for complications who will require closer monitoring after transplantation. Early posttransplant complications include infectious and noninfectious entities. Bacterial, viral, and fungal pneumonias are in the differential of infectious pneumonia, and bronchoscopy can be helpful in establishing a diagnosis. A common, important noninfectious cause of early pulmonary complications is IPS, which is treated with steroids and sometimes anti-TNF therapy.

A study of diagnostic accuracy in the primary care setting showed that among patients receiving inhaled therapies, most had not received an accurate diagnosis of chronic obstructive pulmonary disease (COPD) or asthma according to international guidelines.^1,2 Other studies have shown that up to one-third of patients with a diagnosis of asthma³ or COPD⁴ may not actually have disease based on subsequent lung function testing.

Diagnostic error in medicine leads to numerous lost opportunities including the opportunity to: identify chronic conditions that are the true sources of patients’ symptoms, prevent morbidity and mortality, reduce unnecessary costs to patients and health systems, and deliver high-quality care.^5-7 The reasons for diagnostic error in COPD and asthma are multifactorial, stemming from insufficient knowledge of clinical practice guidelines and underutilization of spirometry testing. Spirometry is recommended as part of the workup for suspected COPD and is the preferred test for diagnosing asthma. Spirometry, combined with clinical findings, can help differentiate between these diseases.

IMAGE © JOE GORMAN

In this article, we review the definitions and characteristics of COPD and asthma, address the potential causes for diagnostic error, and explain how current clinical practice guidelines can steer examinations to the right diagnosis, improve clinical management, and contribute to better patient outcomes and quality of life.^8,9

COPD and asthma characteristics

COPD. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a common lung disease characterized by persistent respiratory symptoms and airflow obstruction caused by airway or alveolar abnormalities secondary to significant exposure to noxious particles or gases.¹⁰ The most common COPD-risk exposure in the United States is tobacco smoke, chiefly from cigarettes. Risk is also heightened with use of other types of tobacco (pipe, cigar, water pipe), indoor and outdoor air pollution (including second-hand tobacco smoke exposure), and occupational exposures. (Consider testing for alpha-1 antitrypsin deficiency—a known genetic risk factor for COPD—especially when an individual with COPD is younger and has a limited smoking history.)

If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

The most common symptom of COPD is chronic, progressive dyspnea — an increased effort to breathe, with chest heaviness, air hunger, or gasping. About one-third of people with COPD have a chronic cough with sputum production.¹⁰ There may be wheezing and chest tightness. Fatigue, weight loss, and anorexia can be seen in severe COPD. Consider this disorder in any individual older than 40 years of age who has dyspnea and chronic cough with sputum production, as well as a history of risk factors. If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

Asthma is usually characterized by variable airway hyperresponsiveness and chronic inflammation. A typical clinical presentation is an individual with a history of wheezing, shortness of breath, chest tightness, and cough that vary in intensity over time and are coupled with variable expiratory flow limitation. Asthma symptoms are often triggered by allergen or irritant exposure, exercise, weather changes, or viral respiratory infections.² Symptoms may also be worse at night or first thing in the morning. Once asthma is suspected, document the presence of airflow variability with spirometry to confirm the diagnosis.

[polldaddy:10261486]

Diagnostic error in suspected COPD and asthma

Numerous studies have demonstrated the prevalence of diagnostic error when testing of lung function is neglected.^11-14 Using spirometry to confirm a prior clinical diagnosis of COPD, researchers found that:

• 35% to 50% of patients did not have objective evidence of COPD^12,13;
• 37% with an asthma-only diagnosis had persistent obstruction, which may indicate COPD or chronic obstructive asthma¹²; and
• 31% of patients thought to have asthma-COPD overlap did not have a COPD component.¹²

Continue to: In 2 longitudinal studies...

In 2 longitudinal studies, patients with a diagnosis of asthma were recruited to undergo medication reduction and serial lung function testing. Asthma was excluded in approximately 30% of patients.^15,16 Diagnostic error has also been seen in patients hospitalized with exacerbations of COPD and asthma. One study found that only 31% of patients admitted with a diagnosis of COPD exacerbation had undergone a spirometry test prior to hospitalization.¹⁷ And of those patients with a diagnosis of COPD who underwent spirometry, 30% had results inconsistent with COPD.¹⁷

In another study, 22% of adults hospitalized for COPD or asthma exacerbations had no evidence of obstruction on spirometry at the time of hospitalization.¹⁸ This finding refutes a diagnosis of COPD and, in the midst of an exacerbation, challenges an asthma diagnosis as well. Increased awareness of clinical practice guidelines, coupled with the use and accurate interpretation of spirometry are needed for optimal management and treatment of COPD and asthma.

Airflow measurement is decisive in diagnosing COPD and asthma

Clinical practice guidelines recommend spirometry for the diagnosis of COPD and asthma and have been issued by GOLD¹⁰; the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and the European Respiratory Society¹⁹; the Global Initiative for Asthma (GINA)²; and the National Heart, Lung, and Blood Institute.²⁰

When a patient’s symptoms and risk factors suggest COPD, spirometry is needed to show persistent post-bronchodilator airflow obstruction and thereby confirm the diagnosis. However, in the United States, confirmatory spirometry is used only in about one third of patients newly diagnosed with COPD.^21,22 Similarly for asthma, in the presence of suggestive symptoms, spirometry is the preferred and most reliable and reproducible test to detect the variable expiratory airflow limitation consistent with this diagnosis.

An alternative to spirometry for the diagnosis of asthma (if needed) is a peak flow meter, a simple tool to measure peak expiratory flow. When compared with spirometry, peak flow measurements are less time consuming, less costly, and not dependent on trained staff to perform.²³ However, this option does require that patients perform and document multiple measurements over several days without an objective assessment of their efforts. Unlike spirometry, the peak flow meter has no reference values or reliability and reproducibility standards, and measurements can differ from one peak flow meter to another. Thus, a peak flow meter is less reliable than spirometry for diagnosing asthma. But it can be useful for monitoring asthma control at home and in the clinic setting,²⁴ or for diagnosis if spirometry is unavailable.²³

Continue to: Barriers to the use of spirometry...

Barriers to the use of spirometry in the primary care setting exist on several levels. Providers may lack knowledge of clinical practice guidelines that recommend spirometry in the diagnosis of COPD, and they may lack general awareness of the utility of spirometry.^25-29 In 2 studies of primary care practices that offered office spirometry, lack of knowledge in conducting and interpreting the test was a barrier to its use.^28,30 Primary care physicians also struggle with logistical challenges when clinical visits last just 10 to 15 minutes for patients with multiple comorbidities,²⁷ and maintenance of an office spirometry program may not always be feasible.

Getting to the right diagnosis

Guideline-based treatment recommendations differ for COPD and asthma, and mistakenly treating the wrong condition can lead to adverse events (AEs). For instance, while inhaled corticosteroids use is common in patients with persistent asthma, its use in COPD increases the risk of pneumonia³¹ and thus is usually reserved for add-on treatment mainly if patients experience continued exacerbations. Use of long-acting beta-agonists (LABAs) as monotherapy is appropriate in COPD but not so in the management of asthma. In 2006, a large randomized controlled trial evaluated a LABA (salmeterol) vs placebo added to usual care and found more serious AEs and asthma-related deaths in the salmeterol group.^32,33 Thus LABA monotherapy is not recommended in asthma guidelines.

Likewise, nonpharmacologic interventions may be misused or go unused when needed if the diagnosis is inaccurate. For patients with COPD, outcomes are improved with pulmonary rehabilitation and supplemental oxygen in the setting of resting hypoxemia, but these resources will not be considered if patients are misdiagnosed as having asthma. A patient with undetected heart failure or obstructive sleep apnea who has been misdiagnosed with COPD or asthma may not receive appropriate diagnostic testing or treatment until asthma or COPD has been ruled out with lung function testing.

Objectively documenting the right diagnosis helps ensure guideline-based management of COPD or asthma. Ruling out these 2 disorders prompts further investigation into other conditions (eg, coronary artery disease, heart failure, gastroesophageal reflux disease, pulmonary hypertension, interstitial lung diseases) that can cause symptoms such as shortness of breath, wheezing, or cough.

The TABLE^2,10,34 summarizes some of the more common clinical and spirometric features of COPD and asthma. Onset of COPD usually occurs in those over age 40. Asthma can present in younger individuals, including children. Tobacco use or exposure to noxious substances is more often associated with COPD. Patients with asthma are more likely to have atopy. Symptoms in COPD usually progress with increasing activity or exertion. Symptoms in asthma may vary with certain activities, such as exercise, and with various triggers. These features represent “typical” cases of COPD or asthma, but some patients may have clinical characteristics that do not fit easily into one disease pattern, making diagnostic testing of lung function even more essential.

Continue to: The utility of spirometry in measuring lung function

The utility of spirometry in measuring lung function. Spirometry is the most reproducible and objective measurement of airflow limitation,¹⁰ and it should precede any treatment decisions. This technique—in which the patient performs maximal inhalation followed by forced exhalation—measures airflow over time and determines the lung volume exhaled at any time point. Because this respiratory exercise is patient dependent, a well-trained technician is needed to ensure reproducibility and reliability of results based on technical standards.

Asthma was excluded in about 30% of patients studied longitudinally who subsequently underwent spirometry.

Spirometry measures forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁), from which the FEV₁/FVC ratio is calculated. FVC is the total amount of air from total lung volume that can be exhaled in one breath. FEV₁ is the total amount of air exhaled in the first second after initiation of exhalation. Thus, the FEV₁/FVC ratio is the percentage of the total amount of air in a single breath that is exhaled in the first second. On average, an individual with normal lungs can exhale approximately 80% of their FVC in the first second, thereby resulting in a FEV₁/FVC ratio of 80%.

Spirometry findings with COPD. A post-bronchodilator FEV₁/FVC ratio of less than 70% confirms airflow obstruction and is consistent with COPD according to GOLD criteria.¹⁰ Post-bronchodilator spirometry is performed after the patient has received a specified dose of an inhaled bronchodilator per lab protocols. In patients with COPD, the FEV₁/FVC ratio is persistently low even after administration of a bronchodilator.

Another means of using spirometry to diagnose COPD is referring to age-dependent cutoff values below the lower fifth percentile of the FEV₁/FVC ratio (ie, lower limit of normal [LLN]), which differs from the GOLD strategy but is consistent with the American Thoracic Society/European Respiratory Society guidelines.³⁵ Because the FEV₁/FVC ratio declines with age, older adults may have a normal post-bronchodilator ratio less than 70%. Admittedly, applying GOLD criteria to older adults could result in overdiagnosis, while using the LLN could lead to underdiagnosis. Although there is no consensus on which method to use, the best approach may be the one that most strongly correlates with pretest probability of disease. In a large Canadian study, the approach that most strongly predicted poor patient outcomes was using a FEV₁/FVC based on fixed (70%) and/or LLN criteria, and a low FEV₁³⁴

Spirometry findings with asthma. According to the American Thoracic Society, a post-bronchodilator response is defined as an increase in FEV₁ (or FVC) of 12% if that volume is also ≥200 mL. In patients with suspected asthma, an increase in FEV₁ ≥12% and 200 mL is consistent with variable airflow limitation² and supports the diagnosis. Of note, lung function in patients with asthma may be normal when patients are not symptomatic or when they are receiving therapy. Spirometry is therefore ideally performed before initiating therapy and when maintenance therapy is being considered due to symptoms. If therapy is clinically indicated, a short-acting bronchodilator may be prescribed alone and then held 6 to 8 hours before conducting spirometry. If a trial of a maintenance medication is prescribed before spirometry, consider de-escalation of therapy once the patient is more stable and then perform spirometry to confirm the presence of airflow variability consistent with asthma. (In COPD, there can be a positive bronchodilator response; however, the post-bronchodilator FEV₁/FVC ratio remains low.)

Continue to: Don't use in isolation

Don’t use in isolation. Use spirometry to support a clinical suspicion of asthma³⁶ or COPD after a thorough history and physical exam, and not in isolation.

Special consideration: Asthma-COPD overlap syndrome

Some patients have features characteristic of both asthma and COPD and are said to have asthma-COPD overlap syndrome (ACOS). Between 15% and 20% of patients with COPD may in fact have ACOS.³⁶ While there is no specific definition of ACOS, GOLD and GINA describe ACOS as persistent airflow limitation with several features usually associated with asthma and several features usually associated with COPD.^2,10,37 ACOS becomes more prevalent with advancing age.

In the United States, confirmatory spirometry is used in only about one-third of patients newly diagnosed with COPD.

In ACOS, patients with COPD present with increased reversibility or patients with asthma and smoking history develop non-fully reversible airway obstruction at an older age.³⁸ Patients with ACOS have worse lung function, more respiratory symptoms, and lower health-related quality of life than individuals with asthma or COPD alone,^39,40 leading to more consumption of medical resources.⁴¹ In patients with ACOS, the FEV₁/FVC ratio is low and consistent with the diagnosis of COPD. The post-bronchodilator response may be variable, depending on the stage of disease and predominant clinical features. It is still unclear whether ACOS is a separate disease entity, a representation of severe asthma that has morphed into COPD, or not a syndrome but simply 2 separate comorbid disease states.

CORRESPONDENCE
Christina D. Wells, MD, University of Illinois Mile Square Health Center, 1220 S. Wood Street, Chicago, IL 60612; [email protected].

A study of diagnostic accuracy in the primary care setting showed that among patients receiving inhaled therapies, most had not received an accurate diagnosis of chronic obstructive pulmonary disease (COPD) or asthma according to international guidelines.^1,2 Other studies have shown that up to one-third of patients with a diagnosis of asthma³ or COPD⁴ may not actually have disease based on subsequent lung function testing.

Diagnostic error in medicine leads to numerous lost opportunities including the opportunity to: identify chronic conditions that are the true sources of patients’ symptoms, prevent morbidity and mortality, reduce unnecessary costs to patients and health systems, and deliver high-quality care.^5-7 The reasons for diagnostic error in COPD and asthma are multifactorial, stemming from insufficient knowledge of clinical practice guidelines and underutilization of spirometry testing. Spirometry is recommended as part of the workup for suspected COPD and is the preferred test for diagnosing asthma. Spirometry, combined with clinical findings, can help differentiate between these diseases.

IMAGE © JOE GORMAN

In this article, we review the definitions and characteristics of COPD and asthma, address the potential causes for diagnostic error, and explain how current clinical practice guidelines can steer examinations to the right diagnosis, improve clinical management, and contribute to better patient outcomes and quality of life.^8,9

COPD and asthma characteristics

COPD. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a common lung disease characterized by persistent respiratory symptoms and airflow obstruction caused by airway or alveolar abnormalities secondary to significant exposure to noxious particles or gases.¹⁰ The most common COPD-risk exposure in the United States is tobacco smoke, chiefly from cigarettes. Risk is also heightened with use of other types of tobacco (pipe, cigar, water pipe), indoor and outdoor air pollution (including second-hand tobacco smoke exposure), and occupational exposures. (Consider testing for alpha-1 antitrypsin deficiency—a known genetic risk factor for COPD—especially when an individual with COPD is younger and has a limited smoking history.)

If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

The most common symptom of COPD is chronic, progressive dyspnea — an increased effort to breathe, with chest heaviness, air hunger, or gasping. About one-third of people with COPD have a chronic cough with sputum production.¹⁰ There may be wheezing and chest tightness. Fatigue, weight loss, and anorexia can be seen in severe COPD. Consider this disorder in any individual older than 40 years of age who has dyspnea and chronic cough with sputum production, as well as a history of risk factors. If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

Asthma is usually characterized by variable airway hyperresponsiveness and chronic inflammation. A typical clinical presentation is an individual with a history of wheezing, shortness of breath, chest tightness, and cough that vary in intensity over time and are coupled with variable expiratory flow limitation. Asthma symptoms are often triggered by allergen or irritant exposure, exercise, weather changes, or viral respiratory infections.² Symptoms may also be worse at night or first thing in the morning. Once asthma is suspected, document the presence of airflow variability with spirometry to confirm the diagnosis.

[polldaddy:10261486]

Diagnostic error in suspected COPD and asthma

Numerous studies have demonstrated the prevalence of diagnostic error when testing of lung function is neglected.^11-14 Using spirometry to confirm a prior clinical diagnosis of COPD, researchers found that:

• 35% to 50% of patients did not have objective evidence of COPD^12,13;
• 37% with an asthma-only diagnosis had persistent obstruction, which may indicate COPD or chronic obstructive asthma¹²; and
• 31% of patients thought to have asthma-COPD overlap did not have a COPD component.¹²

Continue to: In 2 longitudinal studies...

In 2 longitudinal studies, patients with a diagnosis of asthma were recruited to undergo medication reduction and serial lung function testing. Asthma was excluded in approximately 30% of patients.^15,16 Diagnostic error has also been seen in patients hospitalized with exacerbations of COPD and asthma. One study found that only 31% of patients admitted with a diagnosis of COPD exacerbation had undergone a spirometry test prior to hospitalization.¹⁷ And of those patients with a diagnosis of COPD who underwent spirometry, 30% had results inconsistent with COPD.¹⁷

In another study, 22% of adults hospitalized for COPD or asthma exacerbations had no evidence of obstruction on spirometry at the time of hospitalization.¹⁸ This finding refutes a diagnosis of COPD and, in the midst of an exacerbation, challenges an asthma diagnosis as well. Increased awareness of clinical practice guidelines, coupled with the use and accurate interpretation of spirometry are needed for optimal management and treatment of COPD and asthma.

Airflow measurement is decisive in diagnosing COPD and asthma

Clinical practice guidelines recommend spirometry for the diagnosis of COPD and asthma and have been issued by GOLD¹⁰; the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and the European Respiratory Society¹⁹; the Global Initiative for Asthma (GINA)²; and the National Heart, Lung, and Blood Institute.²⁰

When a patient’s symptoms and risk factors suggest COPD, spirometry is needed to show persistent post-bronchodilator airflow obstruction and thereby confirm the diagnosis. However, in the United States, confirmatory spirometry is used only in about one third of patients newly diagnosed with COPD.^21,22 Similarly for asthma, in the presence of suggestive symptoms, spirometry is the preferred and most reliable and reproducible test to detect the variable expiratory airflow limitation consistent with this diagnosis.

An alternative to spirometry for the diagnosis of asthma (if needed) is a peak flow meter, a simple tool to measure peak expiratory flow. When compared with spirometry, peak flow measurements are less time consuming, less costly, and not dependent on trained staff to perform.²³ However, this option does require that patients perform and document multiple measurements over several days without an objective assessment of their efforts. Unlike spirometry, the peak flow meter has no reference values or reliability and reproducibility standards, and measurements can differ from one peak flow meter to another. Thus, a peak flow meter is less reliable than spirometry for diagnosing asthma. But it can be useful for monitoring asthma control at home and in the clinic setting,²⁴ or for diagnosis if spirometry is unavailable.²³

Continue to: Barriers to the use of spirometry...

Barriers to the use of spirometry in the primary care setting exist on several levels. Providers may lack knowledge of clinical practice guidelines that recommend spirometry in the diagnosis of COPD, and they may lack general awareness of the utility of spirometry.^25-29 In 2 studies of primary care practices that offered office spirometry, lack of knowledge in conducting and interpreting the test was a barrier to its use.^28,30 Primary care physicians also struggle with logistical challenges when clinical visits last just 10 to 15 minutes for patients with multiple comorbidities,²⁷ and maintenance of an office spirometry program may not always be feasible.

Getting to the right diagnosis

Guideline-based treatment recommendations differ for COPD and asthma, and mistakenly treating the wrong condition can lead to adverse events (AEs). For instance, while inhaled corticosteroids use is common in patients with persistent asthma, its use in COPD increases the risk of pneumonia³¹ and thus is usually reserved for add-on treatment mainly if patients experience continued exacerbations. Use of long-acting beta-agonists (LABAs) as monotherapy is appropriate in COPD but not so in the management of asthma. In 2006, a large randomized controlled trial evaluated a LABA (salmeterol) vs placebo added to usual care and found more serious AEs and asthma-related deaths in the salmeterol group.^32,33 Thus LABA monotherapy is not recommended in asthma guidelines.

Likewise, nonpharmacologic interventions may be misused or go unused when needed if the diagnosis is inaccurate. For patients with COPD, outcomes are improved with pulmonary rehabilitation and supplemental oxygen in the setting of resting hypoxemia, but these resources will not be considered if patients are misdiagnosed as having asthma. A patient with undetected heart failure or obstructive sleep apnea who has been misdiagnosed with COPD or asthma may not receive appropriate diagnostic testing or treatment until asthma or COPD has been ruled out with lung function testing.

Objectively documenting the right diagnosis helps ensure guideline-based management of COPD or asthma. Ruling out these 2 disorders prompts further investigation into other conditions (eg, coronary artery disease, heart failure, gastroesophageal reflux disease, pulmonary hypertension, interstitial lung diseases) that can cause symptoms such as shortness of breath, wheezing, or cough.

The TABLE^2,10,34 summarizes some of the more common clinical and spirometric features of COPD and asthma. Onset of COPD usually occurs in those over age 40. Asthma can present in younger individuals, including children. Tobacco use or exposure to noxious substances is more often associated with COPD. Patients with asthma are more likely to have atopy. Symptoms in COPD usually progress with increasing activity or exertion. Symptoms in asthma may vary with certain activities, such as exercise, and with various triggers. These features represent “typical” cases of COPD or asthma, but some patients may have clinical characteristics that do not fit easily into one disease pattern, making diagnostic testing of lung function even more essential.

Continue to: The utility of spirometry in measuring lung function

The utility of spirometry in measuring lung function. Spirometry is the most reproducible and objective measurement of airflow limitation,¹⁰ and it should precede any treatment decisions. This technique—in which the patient performs maximal inhalation followed by forced exhalation—measures airflow over time and determines the lung volume exhaled at any time point. Because this respiratory exercise is patient dependent, a well-trained technician is needed to ensure reproducibility and reliability of results based on technical standards.

Asthma was excluded in about 30% of patients studied longitudinally who subsequently underwent spirometry.

Spirometry measures forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁), from which the FEV₁/FVC ratio is calculated. FVC is the total amount of air from total lung volume that can be exhaled in one breath. FEV₁ is the total amount of air exhaled in the first second after initiation of exhalation. Thus, the FEV₁/FVC ratio is the percentage of the total amount of air in a single breath that is exhaled in the first second. On average, an individual with normal lungs can exhale approximately 80% of their FVC in the first second, thereby resulting in a FEV₁/FVC ratio of 80%.

Spirometry findings with COPD. A post-bronchodilator FEV₁/FVC ratio of less than 70% confirms airflow obstruction and is consistent with COPD according to GOLD criteria.¹⁰ Post-bronchodilator spirometry is performed after the patient has received a specified dose of an inhaled bronchodilator per lab protocols. In patients with COPD, the FEV₁/FVC ratio is persistently low even after administration of a bronchodilator.

Another means of using spirometry to diagnose COPD is referring to age-dependent cutoff values below the lower fifth percentile of the FEV₁/FVC ratio (ie, lower limit of normal [LLN]), which differs from the GOLD strategy but is consistent with the American Thoracic Society/European Respiratory Society guidelines.³⁵ Because the FEV₁/FVC ratio declines with age, older adults may have a normal post-bronchodilator ratio less than 70%. Admittedly, applying GOLD criteria to older adults could result in overdiagnosis, while using the LLN could lead to underdiagnosis. Although there is no consensus on which method to use, the best approach may be the one that most strongly correlates with pretest probability of disease. In a large Canadian study, the approach that most strongly predicted poor patient outcomes was using a FEV₁/FVC based on fixed (70%) and/or LLN criteria, and a low FEV₁³⁴

Spirometry findings with asthma. According to the American Thoracic Society, a post-bronchodilator response is defined as an increase in FEV₁ (or FVC) of 12% if that volume is also ≥200 mL. In patients with suspected asthma, an increase in FEV₁ ≥12% and 200 mL is consistent with variable airflow limitation² and supports the diagnosis. Of note, lung function in patients with asthma may be normal when patients are not symptomatic or when they are receiving therapy. Spirometry is therefore ideally performed before initiating therapy and when maintenance therapy is being considered due to symptoms. If therapy is clinically indicated, a short-acting bronchodilator may be prescribed alone and then held 6 to 8 hours before conducting spirometry. If a trial of a maintenance medication is prescribed before spirometry, consider de-escalation of therapy once the patient is more stable and then perform spirometry to confirm the presence of airflow variability consistent with asthma. (In COPD, there can be a positive bronchodilator response; however, the post-bronchodilator FEV₁/FVC ratio remains low.)

Continue to: Don't use in isolation

Don’t use in isolation. Use spirometry to support a clinical suspicion of asthma³⁶ or COPD after a thorough history and physical exam, and not in isolation.

Special consideration: Asthma-COPD overlap syndrome

Some patients have features characteristic of both asthma and COPD and are said to have asthma-COPD overlap syndrome (ACOS). Between 15% and 20% of patients with COPD may in fact have ACOS.³⁶ While there is no specific definition of ACOS, GOLD and GINA describe ACOS as persistent airflow limitation with several features usually associated with asthma and several features usually associated with COPD.^2,10,37 ACOS becomes more prevalent with advancing age.

In the United States, confirmatory spirometry is used in only about one-third of patients newly diagnosed with COPD.

In ACOS, patients with COPD present with increased reversibility or patients with asthma and smoking history develop non-fully reversible airway obstruction at an older age.³⁸ Patients with ACOS have worse lung function, more respiratory symptoms, and lower health-related quality of life than individuals with asthma or COPD alone,^39,40 leading to more consumption of medical resources.⁴¹ In patients with ACOS, the FEV₁/FVC ratio is low and consistent with the diagnosis of COPD. The post-bronchodilator response may be variable, depending on the stage of disease and predominant clinical features. It is still unclear whether ACOS is a separate disease entity, a representation of severe asthma that has morphed into COPD, or not a syndrome but simply 2 separate comorbid disease states.

CORRESPONDENCE
Christina D. Wells, MD, University of Illinois Mile Square Health Center, 1220 S. Wood Street, Chicago, IL 60612; [email protected].

A study of diagnostic accuracy in the primary care setting showed that among patients receiving inhaled therapies, most had not received an accurate diagnosis of chronic obstructive pulmonary disease (COPD) or asthma according to international guidelines.^1,2 Other studies have shown that up to one-third of patients with a diagnosis of asthma³ or COPD⁴ may not actually have disease based on subsequent lung function testing.

Diagnostic error in medicine leads to numerous lost opportunities including the opportunity to: identify chronic conditions that are the true sources of patients’ symptoms, prevent morbidity and mortality, reduce unnecessary costs to patients and health systems, and deliver high-quality care.^5-7 The reasons for diagnostic error in COPD and asthma are multifactorial, stemming from insufficient knowledge of clinical practice guidelines and underutilization of spirometry testing. Spirometry is recommended as part of the workup for suspected COPD and is the preferred test for diagnosing asthma. Spirometry, combined with clinical findings, can help differentiate between these diseases.

IMAGE © JOE GORMAN

In this article, we review the definitions and characteristics of COPD and asthma, address the potential causes for diagnostic error, and explain how current clinical practice guidelines can steer examinations to the right diagnosis, improve clinical management, and contribute to better patient outcomes and quality of life.^8,9

COPD and asthma characteristics

COPD. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a common lung disease characterized by persistent respiratory symptoms and airflow obstruction caused by airway or alveolar abnormalities secondary to significant exposure to noxious particles or gases.¹⁰ The most common COPD-risk exposure in the United States is tobacco smoke, chiefly from cigarettes. Risk is also heightened with use of other types of tobacco (pipe, cigar, water pipe), indoor and outdoor air pollution (including second-hand tobacco smoke exposure), and occupational exposures. (Consider testing for alpha-1 antitrypsin deficiency—a known genetic risk factor for COPD—especially when an individual with COPD is younger and has a limited smoking history.)

If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

The most common symptom of COPD is chronic, progressive dyspnea — an increased effort to breathe, with chest heaviness, air hunger, or gasping. About one-third of people with COPD have a chronic cough with sputum production.¹⁰ There may be wheezing and chest tightness. Fatigue, weight loss, and anorexia can be seen in severe COPD. Consider this disorder in any individual older than 40 years of age who has dyspnea and chronic cough with sputum production, as well as a history of risk factors. If COPD is suspected, perform spirometry to determine the presence of fixed airflow limitation and confirm the diagnosis.

Asthma is usually characterized by variable airway hyperresponsiveness and chronic inflammation. A typical clinical presentation is an individual with a history of wheezing, shortness of breath, chest tightness, and cough that vary in intensity over time and are coupled with variable expiratory flow limitation. Asthma symptoms are often triggered by allergen or irritant exposure, exercise, weather changes, or viral respiratory infections.² Symptoms may also be worse at night or first thing in the morning. Once asthma is suspected, document the presence of airflow variability with spirometry to confirm the diagnosis.

[polldaddy:10261486]

Diagnostic error in suspected COPD and asthma

Numerous studies have demonstrated the prevalence of diagnostic error when testing of lung function is neglected.^11-14 Using spirometry to confirm a prior clinical diagnosis of COPD, researchers found that:

• 35% to 50% of patients did not have objective evidence of COPD^12,13;
• 37% with an asthma-only diagnosis had persistent obstruction, which may indicate COPD or chronic obstructive asthma¹²; and
• 31% of patients thought to have asthma-COPD overlap did not have a COPD component.¹²

Continue to: In 2 longitudinal studies...

In 2 longitudinal studies, patients with a diagnosis of asthma were recruited to undergo medication reduction and serial lung function testing. Asthma was excluded in approximately 30% of patients.^15,16 Diagnostic error has also been seen in patients hospitalized with exacerbations of COPD and asthma. One study found that only 31% of patients admitted with a diagnosis of COPD exacerbation had undergone a spirometry test prior to hospitalization.¹⁷ And of those patients with a diagnosis of COPD who underwent spirometry, 30% had results inconsistent with COPD.¹⁷

In another study, 22% of adults hospitalized for COPD or asthma exacerbations had no evidence of obstruction on spirometry at the time of hospitalization.¹⁸ This finding refutes a diagnosis of COPD and, in the midst of an exacerbation, challenges an asthma diagnosis as well. Increased awareness of clinical practice guidelines, coupled with the use and accurate interpretation of spirometry are needed for optimal management and treatment of COPD and asthma.

Airflow measurement is decisive in diagnosing COPD and asthma

Clinical practice guidelines recommend spirometry for the diagnosis of COPD and asthma and have been issued by GOLD¹⁰; the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and the European Respiratory Society¹⁹; the Global Initiative for Asthma (GINA)²; and the National Heart, Lung, and Blood Institute.²⁰

When a patient’s symptoms and risk factors suggest COPD, spirometry is needed to show persistent post-bronchodilator airflow obstruction and thereby confirm the diagnosis. However, in the United States, confirmatory spirometry is used only in about one third of patients newly diagnosed with COPD.^21,22 Similarly for asthma, in the presence of suggestive symptoms, spirometry is the preferred and most reliable and reproducible test to detect the variable expiratory airflow limitation consistent with this diagnosis.

An alternative to spirometry for the diagnosis of asthma (if needed) is a peak flow meter, a simple tool to measure peak expiratory flow. When compared with spirometry, peak flow measurements are less time consuming, less costly, and not dependent on trained staff to perform.²³ However, this option does require that patients perform and document multiple measurements over several days without an objective assessment of their efforts. Unlike spirometry, the peak flow meter has no reference values or reliability and reproducibility standards, and measurements can differ from one peak flow meter to another. Thus, a peak flow meter is less reliable than spirometry for diagnosing asthma. But it can be useful for monitoring asthma control at home and in the clinic setting,²⁴ or for diagnosis if spirometry is unavailable.²³

Continue to: Barriers to the use of spirometry...

Barriers to the use of spirometry in the primary care setting exist on several levels. Providers may lack knowledge of clinical practice guidelines that recommend spirometry in the diagnosis of COPD, and they may lack general awareness of the utility of spirometry.^25-29 In 2 studies of primary care practices that offered office spirometry, lack of knowledge in conducting and interpreting the test was a barrier to its use.^28,30 Primary care physicians also struggle with logistical challenges when clinical visits last just 10 to 15 minutes for patients with multiple comorbidities,²⁷ and maintenance of an office spirometry program may not always be feasible.

Getting to the right diagnosis

Guideline-based treatment recommendations differ for COPD and asthma, and mistakenly treating the wrong condition can lead to adverse events (AEs). For instance, while inhaled corticosteroids use is common in patients with persistent asthma, its use in COPD increases the risk of pneumonia³¹ and thus is usually reserved for add-on treatment mainly if patients experience continued exacerbations. Use of long-acting beta-agonists (LABAs) as monotherapy is appropriate in COPD but not so in the management of asthma. In 2006, a large randomized controlled trial evaluated a LABA (salmeterol) vs placebo added to usual care and found more serious AEs and asthma-related deaths in the salmeterol group.^32,33 Thus LABA monotherapy is not recommended in asthma guidelines.

Likewise, nonpharmacologic interventions may be misused or go unused when needed if the diagnosis is inaccurate. For patients with COPD, outcomes are improved with pulmonary rehabilitation and supplemental oxygen in the setting of resting hypoxemia, but these resources will not be considered if patients are misdiagnosed as having asthma. A patient with undetected heart failure or obstructive sleep apnea who has been misdiagnosed with COPD or asthma may not receive appropriate diagnostic testing or treatment until asthma or COPD has been ruled out with lung function testing.

Objectively documenting the right diagnosis helps ensure guideline-based management of COPD or asthma. Ruling out these 2 disorders prompts further investigation into other conditions (eg, coronary artery disease, heart failure, gastroesophageal reflux disease, pulmonary hypertension, interstitial lung diseases) that can cause symptoms such as shortness of breath, wheezing, or cough.

The TABLE^2,10,34 summarizes some of the more common clinical and spirometric features of COPD and asthma. Onset of COPD usually occurs in those over age 40. Asthma can present in younger individuals, including children. Tobacco use or exposure to noxious substances is more often associated with COPD. Patients with asthma are more likely to have atopy. Symptoms in COPD usually progress with increasing activity or exertion. Symptoms in asthma may vary with certain activities, such as exercise, and with various triggers. These features represent “typical” cases of COPD or asthma, but some patients may have clinical characteristics that do not fit easily into one disease pattern, making diagnostic testing of lung function even more essential.

Continue to: The utility of spirometry in measuring lung function

The utility of spirometry in measuring lung function. Spirometry is the most reproducible and objective measurement of airflow limitation,¹⁰ and it should precede any treatment decisions. This technique—in which the patient performs maximal inhalation followed by forced exhalation—measures airflow over time and determines the lung volume exhaled at any time point. Because this respiratory exercise is patient dependent, a well-trained technician is needed to ensure reproducibility and reliability of results based on technical standards.

Asthma was excluded in about 30% of patients studied longitudinally who subsequently underwent spirometry.

Spirometry measures forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁), from which the FEV₁/FVC ratio is calculated. FVC is the total amount of air from total lung volume that can be exhaled in one breath. FEV₁ is the total amount of air exhaled in the first second after initiation of exhalation. Thus, the FEV₁/FVC ratio is the percentage of the total amount of air in a single breath that is exhaled in the first second. On average, an individual with normal lungs can exhale approximately 80% of their FVC in the first second, thereby resulting in a FEV₁/FVC ratio of 80%.

Spirometry findings with COPD. A post-bronchodilator FEV₁/FVC ratio of less than 70% confirms airflow obstruction and is consistent with COPD according to GOLD criteria.¹⁰ Post-bronchodilator spirometry is performed after the patient has received a specified dose of an inhaled bronchodilator per lab protocols. In patients with COPD, the FEV₁/FVC ratio is persistently low even after administration of a bronchodilator.

Another means of using spirometry to diagnose COPD is referring to age-dependent cutoff values below the lower fifth percentile of the FEV₁/FVC ratio (ie, lower limit of normal [LLN]), which differs from the GOLD strategy but is consistent with the American Thoracic Society/European Respiratory Society guidelines.³⁵ Because the FEV₁/FVC ratio declines with age, older adults may have a normal post-bronchodilator ratio less than 70%. Admittedly, applying GOLD criteria to older adults could result in overdiagnosis, while using the LLN could lead to underdiagnosis. Although there is no consensus on which method to use, the best approach may be the one that most strongly correlates with pretest probability of disease. In a large Canadian study, the approach that most strongly predicted poor patient outcomes was using a FEV₁/FVC based on fixed (70%) and/or LLN criteria, and a low FEV₁³⁴

Spirometry findings with asthma. According to the American Thoracic Society, a post-bronchodilator response is defined as an increase in FEV₁ (or FVC) of 12% if that volume is also ≥200 mL. In patients with suspected asthma, an increase in FEV₁ ≥12% and 200 mL is consistent with variable airflow limitation² and supports the diagnosis. Of note, lung function in patients with asthma may be normal when patients are not symptomatic or when they are receiving therapy. Spirometry is therefore ideally performed before initiating therapy and when maintenance therapy is being considered due to symptoms. If therapy is clinically indicated, a short-acting bronchodilator may be prescribed alone and then held 6 to 8 hours before conducting spirometry. If a trial of a maintenance medication is prescribed before spirometry, consider de-escalation of therapy once the patient is more stable and then perform spirometry to confirm the presence of airflow variability consistent with asthma. (In COPD, there can be a positive bronchodilator response; however, the post-bronchodilator FEV₁/FVC ratio remains low.)

Continue to: Don't use in isolation

Don’t use in isolation. Use spirometry to support a clinical suspicion of asthma³⁶ or COPD after a thorough history and physical exam, and not in isolation.

Special consideration: Asthma-COPD overlap syndrome

Some patients have features characteristic of both asthma and COPD and are said to have asthma-COPD overlap syndrome (ACOS). Between 15% and 20% of patients with COPD may in fact have ACOS.³⁶ While there is no specific definition of ACOS, GOLD and GINA describe ACOS as persistent airflow limitation with several features usually associated with asthma and several features usually associated with COPD.^2,10,37 ACOS becomes more prevalent with advancing age.

In the United States, confirmatory spirometry is used in only about one-third of patients newly diagnosed with COPD.

In ACOS, patients with COPD present with increased reversibility or patients with asthma and smoking history develop non-fully reversible airway obstruction at an older age.³⁸ Patients with ACOS have worse lung function, more respiratory symptoms, and lower health-related quality of life than individuals with asthma or COPD alone,^39,40 leading to more consumption of medical resources.⁴¹ In patients with ACOS, the FEV₁/FVC ratio is low and consistent with the diagnosis of COPD. The post-bronchodilator response may be variable, depending on the stage of disease and predominant clinical features. It is still unclear whether ACOS is a separate disease entity, a representation of severe asthma that has morphed into COPD, or not a syndrome but simply 2 separate comorbid disease states.

CORRESPONDENCE
Christina D. Wells, MD, University of Illinois Mile Square Health Center, 1220 S. Wood Street, Chicago, IL 60612; [email protected].

Patients infected with HIV have an increased risk of mortality and morbidity from diseases that are preventable with vaccines. Undervaccination of these patients poses a major concern, according to a literature review of the vaccine response in the adult patient with HIV published in The American Journal of Medicine.

copyright itsmejust/Thinkstock

Despite the fact that data are limited, patients infected with HIV are advised to receive their age-specific and risk group−based vaccines, according to Firas El Chaer, MD, of the University of Maryland, Baltimore, and his colleague.

HIV patients are of particular concern regarding vaccination, because, despite the use of retroviral therapy, CD4+ T-lymphocytes in individuals infected with HIV remain lower than in those without HIV. In addition, HIV causes an inappropriate response to B-cell stimulation, which results in suboptimal primary and secondary response to vaccination, according to Dr. El Chaer and his colleague. Despite this and initial concerns about vaccine safety in this population, it is now recommended that adult patients infected with HIV receive their age-specific and risk group−based vaccines, they stated.
 

Inactivated or subunit vaccines

Haemophilus influenzae type b vaccine is not recommended under current guidelines for individuals older than age 18 with HIV infection, unless they have a clinical indication.

Vaccination against hepatitis A virus is recommended for HIV-infected patients who are hepatitis A virus seronegative and have chronic liver disease, men who have sex with men, intravenous drug users, and travelers to endemic regions. However, research has shown that the immunogenicity of the vaccine is lower in patients with HIV than in uninfected individuals. It was found that the CD4 count at the time of vaccination, not the CD4 low point, was the major predictor of the immune response.

Patients coinfected with HIV and hepatitis B virus have an 8-fold and 19-fold increase in mortality, respectively, compared with either virus monoinfection. Although vaccination is recommended, the optimal hepatitis B virus vaccination schedule in patients with HIV remains controversial, according to the authors. They indicated that new strategies to improve hepatitis B virus vaccine immunogenicity for those infected with HIV are needed.

Individuals infected with HIV have been found to have a higher risk of human papillomavirus (HPV) infection. The safety and immunogenicity results and prospect of benefits has led to a consensus on the benefit of vaccinating HIV-infected patients who meet the HPV vaccine age criteria, the authors indicated.

With regard to standard flu vaccinations: “An annual inactivated influenza vaccine is recommended during the influenza season for all adult individuals with HIV; however, a live attenuated influenza vaccine is contraindicated in this population,” according to the review.

Patients with HIV have a more than 10-fold increased risk of invasive meningococcal disease, compared with the general population, with the risk being particularly higher in those individuals with CD4 counts less than 200 cells/mm³ and in men who have sex with men in cities with meningococcal outbreaks. For these reasons, the “quadrivalent meningococcal vaccine is recommended for all patients with HIV regardless of their CD4 count, with 2-dose primary series at least 2 months apart and with a booster every 5 years.”

Pneumonia is known to be especially dangerous in the HIV-infected population. With regard to pneumonia vaccination, the 13-valent pneumococcal conjugate vaccine is recommended for all patients with HIV, regardless of their CD4 cell counts. According to Dr. El Chaer and his colleague, it should be followed by the 23-valent pneumococcal polysaccharide vaccine at least 8 weeks later as a prime-boost regimen, preferably when CD4 counts are greater than 200 cells/mm³ and in patients receiving ART.

“Tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccines are recommended once for all individuals infected with HIV, regardless of the CD4 count, with a tetanus toxoid and diphtheria toxoid booster every 10 years,” according to the review.
 

Live vaccines

Live vaccines are a concerning issue for HIV-infected adults and recommendations for use are generally tied to the CD4 T-cell count. The measles, mumps, and rubella vaccine seems to be safe in patients infected with HIV with a CD4 count greater than 200 cells/mm³, according to Dr. El Chaer and his colleague. Similarly, patients with HIV with CD4 counts greater than 200 cells/mm³ and no evidence of documented immunity to varicella should receive the varicella vaccine.

In contrast, the live, attenuated varicella zoster virus vaccine is not recommended for patients infected with HIV, and it is contraindicated if CD4 count is less than 200 cells/mm³. Recently, a herpes zoster subunit vaccine (HZ/su) was tested in a phase 1/2a randomized, placebo-controlled study and was found to be safe and immunogenic regardless of CD4 count, although it has not yet been given a specific recommendation for immunocompromised patients.

“With the widespread use of ART resulting in better HIV control, clinical vaccine development plans should include patients with HIV and other at-risk populations because they often carry much of the disease burden,” the authors concluded.

The study was not sponsored. Dr. El Chaer and his colleague reported that they had no conflicts.

[email protected]

SOURCE: El Chaer F et al. Am J Med. 2019. doi: 10.1016/j.amjmed.2018.12.011.

Patients infected with HIV have an increased risk of mortality and morbidity from diseases that are preventable with vaccines. Undervaccination of these patients poses a major concern, according to a literature review of the vaccine response in the adult patient with HIV published in The American Journal of Medicine.

copyright itsmejust/Thinkstock

Despite the fact that data are limited, patients infected with HIV are advised to receive their age-specific and risk group−based vaccines, according to Firas El Chaer, MD, of the University of Maryland, Baltimore, and his colleague.

HIV patients are of particular concern regarding vaccination, because, despite the use of retroviral therapy, CD4+ T-lymphocytes in individuals infected with HIV remain lower than in those without HIV. In addition, HIV causes an inappropriate response to B-cell stimulation, which results in suboptimal primary and secondary response to vaccination, according to Dr. El Chaer and his colleague. Despite this and initial concerns about vaccine safety in this population, it is now recommended that adult patients infected with HIV receive their age-specific and risk group−based vaccines, they stated.
 

Inactivated or subunit vaccines

Haemophilus influenzae type b vaccine is not recommended under current guidelines for individuals older than age 18 with HIV infection, unless they have a clinical indication.

Vaccination against hepatitis A virus is recommended for HIV-infected patients who are hepatitis A virus seronegative and have chronic liver disease, men who have sex with men, intravenous drug users, and travelers to endemic regions. However, research has shown that the immunogenicity of the vaccine is lower in patients with HIV than in uninfected individuals. It was found that the CD4 count at the time of vaccination, not the CD4 low point, was the major predictor of the immune response.

Patients coinfected with HIV and hepatitis B virus have an 8-fold and 19-fold increase in mortality, respectively, compared with either virus monoinfection. Although vaccination is recommended, the optimal hepatitis B virus vaccination schedule in patients with HIV remains controversial, according to the authors. They indicated that new strategies to improve hepatitis B virus vaccine immunogenicity for those infected with HIV are needed.

Individuals infected with HIV have been found to have a higher risk of human papillomavirus (HPV) infection. The safety and immunogenicity results and prospect of benefits has led to a consensus on the benefit of vaccinating HIV-infected patients who meet the HPV vaccine age criteria, the authors indicated.

With regard to standard flu vaccinations: “An annual inactivated influenza vaccine is recommended during the influenza season for all adult individuals with HIV; however, a live attenuated influenza vaccine is contraindicated in this population,” according to the review.

Patients with HIV have a more than 10-fold increased risk of invasive meningococcal disease, compared with the general population, with the risk being particularly higher in those individuals with CD4 counts less than 200 cells/mm³ and in men who have sex with men in cities with meningococcal outbreaks. For these reasons, the “quadrivalent meningococcal vaccine is recommended for all patients with HIV regardless of their CD4 count, with 2-dose primary series at least 2 months apart and with a booster every 5 years.”

Pneumonia is known to be especially dangerous in the HIV-infected population. With regard to pneumonia vaccination, the 13-valent pneumococcal conjugate vaccine is recommended for all patients with HIV, regardless of their CD4 cell counts. According to Dr. El Chaer and his colleague, it should be followed by the 23-valent pneumococcal polysaccharide vaccine at least 8 weeks later as a prime-boost regimen, preferably when CD4 counts are greater than 200 cells/mm³ and in patients receiving ART.

“Tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccines are recommended once for all individuals infected with HIV, regardless of the CD4 count, with a tetanus toxoid and diphtheria toxoid booster every 10 years,” according to the review.
 

Live vaccines

Live vaccines are a concerning issue for HIV-infected adults and recommendations for use are generally tied to the CD4 T-cell count. The measles, mumps, and rubella vaccine seems to be safe in patients infected with HIV with a CD4 count greater than 200 cells/mm³, according to Dr. El Chaer and his colleague. Similarly, patients with HIV with CD4 counts greater than 200 cells/mm³ and no evidence of documented immunity to varicella should receive the varicella vaccine.

In contrast, the live, attenuated varicella zoster virus vaccine is not recommended for patients infected with HIV, and it is contraindicated if CD4 count is less than 200 cells/mm³. Recently, a herpes zoster subunit vaccine (HZ/su) was tested in a phase 1/2a randomized, placebo-controlled study and was found to be safe and immunogenic regardless of CD4 count, although it has not yet been given a specific recommendation for immunocompromised patients.

“With the widespread use of ART resulting in better HIV control, clinical vaccine development plans should include patients with HIV and other at-risk populations because they often carry much of the disease burden,” the authors concluded.

The study was not sponsored. Dr. El Chaer and his colleague reported that they had no conflicts.

[email protected]

SOURCE: El Chaer F et al. Am J Med. 2019. doi: 10.1016/j.amjmed.2018.12.011.

Patients infected with HIV have an increased risk of mortality and morbidity from diseases that are preventable with vaccines. Undervaccination of these patients poses a major concern, according to a literature review of the vaccine response in the adult patient with HIV published in The American Journal of Medicine.

copyright itsmejust/Thinkstock

Despite the fact that data are limited, patients infected with HIV are advised to receive their age-specific and risk group−based vaccines, according to Firas El Chaer, MD, of the University of Maryland, Baltimore, and his colleague.

HIV patients are of particular concern regarding vaccination, because, despite the use of retroviral therapy, CD4+ T-lymphocytes in individuals infected with HIV remain lower than in those without HIV. In addition, HIV causes an inappropriate response to B-cell stimulation, which results in suboptimal primary and secondary response to vaccination, according to Dr. El Chaer and his colleague. Despite this and initial concerns about vaccine safety in this population, it is now recommended that adult patients infected with HIV receive their age-specific and risk group−based vaccines, they stated.
 

Inactivated or subunit vaccines

Haemophilus influenzae type b vaccine is not recommended under current guidelines for individuals older than age 18 with HIV infection, unless they have a clinical indication.

Vaccination against hepatitis A virus is recommended for HIV-infected patients who are hepatitis A virus seronegative and have chronic liver disease, men who have sex with men, intravenous drug users, and travelers to endemic regions. However, research has shown that the immunogenicity of the vaccine is lower in patients with HIV than in uninfected individuals. It was found that the CD4 count at the time of vaccination, not the CD4 low point, was the major predictor of the immune response.

Patients coinfected with HIV and hepatitis B virus have an 8-fold and 19-fold increase in mortality, respectively, compared with either virus monoinfection. Although vaccination is recommended, the optimal hepatitis B virus vaccination schedule in patients with HIV remains controversial, according to the authors. They indicated that new strategies to improve hepatitis B virus vaccine immunogenicity for those infected with HIV are needed.

Individuals infected with HIV have been found to have a higher risk of human papillomavirus (HPV) infection. The safety and immunogenicity results and prospect of benefits has led to a consensus on the benefit of vaccinating HIV-infected patients who meet the HPV vaccine age criteria, the authors indicated.

With regard to standard flu vaccinations: “An annual inactivated influenza vaccine is recommended during the influenza season for all adult individuals with HIV; however, a live attenuated influenza vaccine is contraindicated in this population,” according to the review.

Patients with HIV have a more than 10-fold increased risk of invasive meningococcal disease, compared with the general population, with the risk being particularly higher in those individuals with CD4 counts less than 200 cells/mm³ and in men who have sex with men in cities with meningococcal outbreaks. For these reasons, the “quadrivalent meningococcal vaccine is recommended for all patients with HIV regardless of their CD4 count, with 2-dose primary series at least 2 months apart and with a booster every 5 years.”

Pneumonia is known to be especially dangerous in the HIV-infected population. With regard to pneumonia vaccination, the 13-valent pneumococcal conjugate vaccine is recommended for all patients with HIV, regardless of their CD4 cell counts. According to Dr. El Chaer and his colleague, it should be followed by the 23-valent pneumococcal polysaccharide vaccine at least 8 weeks later as a prime-boost regimen, preferably when CD4 counts are greater than 200 cells/mm³ and in patients receiving ART.

“Tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccines are recommended once for all individuals infected with HIV, regardless of the CD4 count, with a tetanus toxoid and diphtheria toxoid booster every 10 years,” according to the review.