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Enoxaparin vs Continuous Heparin for Periprocedural Bridging in Patients With Atrial Fibrillation and Advanced Chronic Kidney Disease
There has been a long-standing controversy in the use of parenteral anticoagulation for perioperative bridging in patients with atrial fibrillation (AF) pursuing elective surgery.1 The decision to bridge is dependent on the patient’s risk of thromboembolic complications and susceptibility to bleed.1 The BRIDGE trial showed noninferiority in rate of stroke and embolism events between low molecular weight heparins (LMWHs) and no perioperative bridging.2 However, according to the American College of Chest Physicians (CHEST) 2012 guidelines, patients in the BRIDGE trial would be deemed low risk for thromboembolic events displayed by a mean CHADS2 (congestive heart failure [CHF], hypertension, age, diabetes mellitus, and stroke/transient ischemic attack) score of 2.3. Also, the BRIDGE study and many others excluded patients with advanced forms of chronic kidney disease (CKD).2,3
Similar to patients with AF, patients with advanced CKD (ACKD, stage 4 and 5 CKD) have an increased risk of stroke and venous thromboembolism (VTE).4,5 Patients with AF and ACKD have not been adequately studied for perioperative anticoagulation bridging outcomes. Although unfractionated heparin (UFH) is preferred over LMWH in ACKD patients,enoxaparin can be used in this population.1,6 Enoxaparin 1 mg/kg once daily is approved by the US Food and Drug Administration (FDA) for use in patients with severe renal insufficiency defined as creatinine clearance (CrCl) < 30 mL/min. This dosage adjustment is subsequent to studies with enoxaparin 1 mg/kg twice daily that showed a significant increase in major and minor bleeding in severe renal-insufficient patients with CrCl < 30 mL/min vs patients with CrCl > 30 mL/min.7 When comparing the myocardial infarction (MI) outcomes of severe renal-insufficient patients in the ExTRACT-TIMI 25 trial, enoxaparin 1 mg/kg once daily had no significant difference in nonfatal major bleeding vs UFH.8 In patients without renal impairment (no documentation of kidney disease), bridging therapy with LMWH was completed more than UFH in < 24 hours of hospital stay and with similar rates of VTEs and major bleeding.9 In addition to its ability to be administered outpatient, enoxaparin has a more predictable pharmacokinetic profile, allowing for less monitoring and a lower incidence of heparin-induced thrombocytopenia (HIT) vs that of UFH.6
The Michael E. DeBakey Veteran Affairs Medical Center (MEDVAMC) in Houston, Texas, is one of the largest US Department of Veterans Affairs (VA) hospitals in the US, managing > 150,000 veterans in Southeast Texas and other southern states. As a referral center for traveling patients, it is crucial that MEDVAMC decrease hospital length of stay (LOS) to increase space for incoming patients. Reducing LOS also reduces costs and may have a correlation with decreasing the incidence of nosocomial infections. Because of its significance to this facility, hospital LOS is an appropriate primary outcome for this study.
To our knowledge, bridging outcomes between LMWH and UFH in patients with AF and ACKD have never been studied. We hypothesized that using enoxaparin instead of heparin for periprocedural management would result in decreased hospital LOS, leading to a lower economic burden and lower incidence of nosocomial infections with no significant differences in major and minor bleeding and thromboembolic complications.10
Methods
This study was a single-center, retrospective chart review of adult patients from January 2008 to September 2017. The review was conducted at MEDVAMC and was approved by the research and development committee and by the Baylor College of Medicine Institutional Review Board. Formal consent was not required.
Included patients were aged ≥ 18 years with diagnoses of AF or atrial flutter and ACKD as recognized by a glomerular filtration rate (eGFR) of < 30 mL/min/1.73 m2 as calculated by use of the Modification of Diet in Renal Disease Study (MDRD) equation.11 Patients must have previously been on warfarin and required temporary interruption of warfarin for an elective procedure. During the interruption of warfarin therapy, a requirement was set for patients to be on periprocedural anticoagulation with subcutaneous (SC) enoxaparin 1 mg/kg daily or continuous IV heparin per MEDVAMC heparin protocol. Patients were excluded if they had experienced major bleeding in the 6 weeks prior to the elective procedure, had current thrombocytopenia (platelet count < 100 × 109/L), or had a history of heparin-induced thrombocytopenia (HIT) or a heparin allergy.
This patient population was identified using TheraDoc Clinical Surveillance Software System (Charlotte, NC), which has prebuilt alert reviews for anticoagulation medications, including enoxaparin and heparin. An alert for patients on enoxaparin with serum creatinine (SCr) > 1.5 mg/dL was used to screen patients who met the inclusion criteria. A second alert identified patients on heparin. The VA Computerized Patient Record System (CPRS) was used to collect patient data.
Economic Analysis
An economic analysis was conducted using data from the VA Managerial Cost Accounting Reports. Data on the national average cost per bed day was used for the purpose of extrapolating this information to multiple VA institutions.12 National average cost per day was determined by dividing the total cost by the number of bed days for the identified treating specialty during the fiscal period of 2018. Average cost per day data included costs for bed day, surgery, radiology services, laboratory tests, pharmacy services, treatment location (ie, intensive care units [ICUs]) and all other costs associated with an inpatient stay. A cost analysis was performed using this average cost per bed day and the mean LOS between enoxaparin and UFH for each treating specialty. The major outcome of the cost analysis was the total cost per average inpatient stay. The national average cost per bed day for each treating specialty was multiplied by the average LOS found for each treating specialty in this study; the sum of all the average costs per inpatient stay for the treating specialties resulted in the total cost per average inpatient stay. Permission to use these data was granted by the Pharmacy and Critical Care Services at MEDVAMC.
Patient Demographics and Characteristics
Data were collected on patient demographics (Table 1). Nosocomial infections, stroke/transient ischemic attack, MI, VTE, major and minor bleeding, and death are defined in Table 2.
The primary outcome of the study was hospital LOS. The study was powered at 90% for α = .05, which gives a required study population of 114 (1:1 enrollment ratio) patients to determine a statistically significant difference in hospital stay. This sample size was calculated using the mean hospital LOS (the primary objective) in the REGIMEN registry for LMWH (4.6 days) and UFH (10.3 days).9 To our knowledge, the incidence of nosocomial infections (a secondary outcome) has not been studied in this patient population; therefore, there was no basis to assess an appropriate sample size to find a difference in this outcome. Furthermore, the goal was to collect as many patients as possible to best assess this variable. Because of an expected high exclusion rate, 504 patients were reviewed to target a sample size of 120 patients. Due to the single-center nature of this review, the secondary outcomes of thromboembolic complications and major and minor bleeding were expected to be underpowered.
The final analysis compared the enoxaparin arm with the UFH arm. Univariate differences between the treatment groups were compared using the Fisher exact test for categorical variables. Demographic data and other continuous variables were analyzed by an unpaired t test to compare means between the 2 arms. Outcomes and characteristics were deemed statistically significant when α (P value) was < .05. All P values reported were 2-tailed with a 95% CI. No statistical analysis was performed for the cost differences (based on LOS per treating specialty) in the 2 treatment arms. Statistical analyses were completed by utilizing GraphPad Software (San Diego, CA).
Results
In total, 50 patients were analyzed in the study. There were 36 patients bridged with IV UFH at a concentration of 25,000 U/250 mL with an initial infusion rate of 12 U/kg/h. For the other arm, 14 patients were anticoagulated with renally dosed enoxaparin 1 mg/kg/d with an average daily dose of 89.3 mg; the mean actual body weight in this group was 90.9 mg (correlates with enoxaparin daily dose). Physicians of the primary team decided which parenteral anticoagulant to use. The difference in mean duration of inpatient parental anticoagulation between both groups was not statistically significant: enoxaparin at 7.1 days and UFH at 9.6 days (P = .19). Patients in the enoxaparin arm were off warfarin therapy for an average of 6.0 days vs 7.5 days for the UFH group (P = .29). The duration of outpatient anticoagulation with enoxaparin was not analyzed in this study.
Patient and Procedure Characteristics
All patients had AF or atrial flutter with 86% of patients (n = 43) having a CHADS2 > 2 and 48% (n = 29) having a CHA2DS2VASc > 4. Overall, the mean age was 71.3 years with similarities in ethnicity distribution. Patients had multiple comorbidities as shown by a mean Charlson Comorbidity Index (CCI) of 7.7 and an increased risk of bleeding as evidenced by 98% (n = 48) of patients having a HAS-BLED score of ≥ 3. A greater percentage of patients bridged with enoxaparin had DM, history of stroke and MI, and a heart valve, whereas UFH patients were more likely to be in stage 5 CKD (eGFR < 15 mL/min/1.73m2) with a significantly lower mean eGFR (16.76 vs 22.64, P = .03). Furthermore, there were more patients on hemodialysis in the UFH (50%) arm vs enoxaparin (21%) arm and a lower mean CrCl with UFH (20.1 mL/min) compared with enoxaparin (24.9 mL/min); however, the differences in hemodialysis and mean CrCl were not statistically significant. There were no patients on peritoneal dialysis in this review.
Procedure Characteristics
The average Revised Cardiac Risk Index (RCRI) score was about 3, indicating that these patients were at a Class IV risk (11%) of having a perioperative cardiac event (Table 3). Nineteen patients (38%) elected for a major surgery with all but 1 of the surgeries (major or minor) being invasive. The average length of surgery was 1.2 hours, and patients were more likely to undergo cardiothoracic procedures (38%). There were 2 out of 14 (14%) patients on enoxaparin who were able to have surgery as an outpatient; whereas this did not occur in patients on UFH. The procedures completed for these patients were a colostomy (minor surgery) and arteriovenous graft repair (major surgery). There were no statistically significant differences regarding types of procedures between the 2 arms.
Outcomes
The primary outcome of this study, hospital LOS, differed significantly in the enoxaparin arm vs UFH: 10.2 days vs 17.5 days, P = .04 (Table 4). The time-to-discharge from initiation of parenteral anticoagulation was significantly reduced with enoxaparin (7.1 days) compared with UFH (11.9 days); P = .04. Although also reduced in the enoxaparin arm, ICU LOS did not show statistical significance (1.1 days vs 4.0 days, P = .09).
About 36% (n = 18) of patients in this study acquired an infection during hospitalization for elective surgery. The most common microorganism and site of infection were Enterococcus species and urinary tract, respectively (Table 5). Nearly half (44%, n = 16) of the patients in the UFH group had a nosocomial infection vs 14% (n = 2) of enoxaparin-bridged patients with a difference approaching significance; P = .056. Both patients in the enoxaparin group had the urinary tract as the primary source of infection; 1 of these patients had a urologic procedure.
Major bleeding occurred in 7% (n = 1) of enoxaparin patients vs 22% (n = 8) in the UFH arm, but this was not found to be statistically significant (P = .41). Minor bleeding was similar between enoxaparin and UFH arms (14% vs 19%, P = .99). Regarding thromboembolic complications, the enoxaparin group (0%) had a numerical reduction compared to UFH (11%) with VTE (n = 4) being the only occurrence of the composite outcome (P = .57). There were 4 deaths within 30 days posthospitalization—all were from the UFH group (P = .57). Due to the small sample size of this study, these outcomes (bleeding and thrombotic events) were not powered to detect a statistically significant difference.
Economic Analysis
The average cost differences (Table 6) of hospitalization between enoxaparin and UFH were calculated using the average LOS per treating specialty multiplied by the national average cost of the MCO for an inpatient bed day in 2018.12 The treating specialty with the longest average LOS in the enoxaparin arm was thoracic (4.7 days). The UFH arm also had a large LOS (average days) for the thoracic specialty (6.4 days); however, the vascular specialty (6.7 days) had the longest average LOS in this group. Due to a mean LOS of 10.2 days in the enoxaparin arm, which was further stratified by treating specialty, the total cost per average inpatient stay was calculated as $51,710. On the other hand, patients in the UFH arm had a total cost per average inpatient stay of $92,848.
Monitoring
Anti-factor Xa levels for LMWH monitoring were not analyzed in this study due to a lack of values collected; only 1 patient had an anti-factor Xa level checked during this time frame. Infusion rates of UFH were adjusted based on aPTT levels collected per MEDVAMC inpatient anticoagulation protocol. The average percentage of aPTT in therapeutic range was 46.3% and the mean time-to-therapeutic range (SD) was about 2.4 (1.3) days. Due to this study’s retrospective nature, there were inconsistencies with availability of documentation of UFH infusion rates. For this reason, these values were not analyzed further.
Discussion
In 2017, the American College of Cardiology published the Periprocedural Anticoagulation Expert Consensus Pathway, which recommends for patients with AF at low risk (CHA2DS2VASc 1-4) of thromboembolism to not be bridged (unless patient had a prior VTE or stroke/TIA).13 Nearly half the patients in this study, were classified as moderate-to-high thrombotic risk as evidenced by a CHA2DS2VASc > 4 with a mean score of 4.8. Due to this study’s retrospective design from 2008 to 2017, many of the clinicians may have referenced the 2008 CHEST antithrombotic guidelines when making the decision to bridge patients; these guidelines and the previous MEDVAMC anticoagulation protocol recommend bridging patients with AF with CHADS2 > 2 (moderate-to-high thrombotic risk) in which all but 1 of the patients in this study met criteria.1,14 In contrast to the landmark BRIDGE trial, the mean CHADS2 score in this study was 3.6; this is an indication that our patient population was of individuals at an increased risk of stroke and embolism.
In addition to thromboembolic complications, patients in the current study also were at increased risk of clinically relevant bleeding with a mean HAS-BLED score of 4.1 and nearly all patients having a score > 3. The complexity of the veteran population also was displayed by this study’s mean CCI (7.7) and RCRI (3.0) indicating a 0% estimated 10-year survival and a 11% increase in having a perioperative cardiac event, respectively. A mean CCI of 7.7 is associated with a 13.3 relative risk of death within 6 years postoperation.15 All patients had a diagnosis of hypertension, and > 75% had this diagnosis complicated by DM. In addition, this patient population was of those with extensive cardiovascular disease or increased risk, which makes for a clinically relevant application of patients who would require periprocedural bridging.
Another positive aspect of this study is that all the baseline characteristics, apart from renal function, were similar between arms, helping to strengthen the ability to adequately compare the 2 bridging modalities. Our assumption for the reasoning that more stage 5 CKD and dialysis patients were anticoagulated with UFH vs enoxaparin is a result of concern for an increased risk of bleeding with a medication that is renally cleared 30% less in CrCl < 30 mL/min.16 Although, enoxaparin 1 mg/kg/d is FDA approved as a therapeutic anticoagulant option, clinicians at MEDVAMC likely had reservations about its use in end-stage CKD patients. Unlike many studies, including the BRIDGE trial, patients with ACKD were not excluded from this trial, and the outcomes with enoxaparin are available for interpretation.
To no surprise, for patients included in this study, enoxaparin use led to shorter hospital LOS, reduced ICU LOS, and a quicker time-to-discharge from initiation. This is credited to the 100% bioavailability of SC enoxaparin in conjunction with its means to be a therapeutic option as an outpatient.16 Unlike IV UFH, patients requiring bridging can be discharged on SC injections of enoxaparin until a therapeutic INR is maintained with warfarin.The duration of hospital LOS in both arms were longer in this study compared with that of other studies.9 This may be due to clinicians being more cautious with renal insufficient patients, and the patients included in this study had multiple comorbidities. According to an economic analysis performed by Amorosi and colleagues in 2004, bridging with enoxaparin instead of UFH can save up to $3,733 per patient and reduce bridging costs by 63% to 85% driven primarily by decreased hospital LOS.10
Economic Outcome
In our study, we conducted a cost analysis using national VA data that indicated a $41,138 or 44% reduction in total cost per average inpatient stay when bridging 1 patient with enoxaparin vs UFH. The benefit of this cost analysis is that it reflects direct costs at VA institutions nationally; this will allow these data to be useful for practitioners at MEDVAMC and other VA hospitals. Stratifying the costs by treating specialty instead of treatment location minimized skewing of the data as there were some patients with long LOS in the ICU. No patients in the enoxaparin arm were treated in otolaryngology, which may have skewed the data. The data included direct costs for beds as well as costs for multiple services, such as procedures, pharmacy, nursing, laboratory tests, and imaging. Unlike the Amorosi study, our review did not include acquisition costs for enoxaparin syringes and bags of UFH or laboratory costs for aPTT and anti-factor Xa levels in part because of the data source and the difficulty calculating costs over a 10-year span.
Patients in the enoxaparin arm had a trend toward fewer occurrences of hospital-acquired infections than did those in the UFH arm, which we believe is due to a decreased LOS (in both total hospital and ICU days) and fewer blood draws needed for monitoring. This also may be attributed to a longer mean duration of surgery in the UFH arm (1.3 hours) vs enoxaparin (0.9 hours). The percentage of patients with procedures ≥ 45 minutes and the types of procedures between both arms were similar. However, these outcomes were not statistically significant. In addition, elderly males who are hospitalized may require a catheter (due to urinary retention), and catheter-associated urinary tract infection (CAUTI) is one of the highest reported infections in acute care hospitals in the US. This is in line with our patient population and may be a supplementary reason for the increase in infection incidence with UFH. Though, whether urinary catheters were used in these patients was not evaluated in this study.
Despite being at an increased risk of experiencing a major adverse cardiovascular event (MACE), no patients in either arm had a stroke/TIA or MI within 30 days postprocedure. The only occurrences documented were VTEs, which happened only in 4 patients on UFH. Four people died in this study, solely in the UFH arm. The incidence of thromboembolic complications and death along with major and minor bleeding cannot be deduced as meaningful as this study was underpowered for these outcomes. Despite anti-factor Xa monitoring being recommended in ACKD patients on enoxaparin, this monitoring was not routinely performed in this study. Another limitation was the inability to adequately assess the appropriateness of nurse-adjusted UFH infusion rates largely due to the retrospective nature of this study. The variability of aPTT percentage in therapeutic range and time-to-therapeutic range reported was indicative of the difficulties of monitoring for the safety and efficacy of UFH.
In 1991, Cruickshank and colleagues conducted a study in which a standard nomogram (similar to the MEDVAMC nomogram) for the adjustment of IV heparin was implemented at a single hospital.17 The success rate (aPTT percentage in therapeutic range) was 59.4% and average time-to-therapeutic range was about 1 day. The success rate (46.3%) and time-to-therapeutic range (2.4 days) in our study were lower and longer, respectively, than was expected. One potential reason for this discrepancy could be the differences in indication as the patients in Cruickshank and colleagues were being treated for VTE, whereas patients in our study had AF or atrial flutter. Also, there were inconsistencies in the availability of documentation of monitoring parameters for heparin due to the study time frame and retrospective design. Patients on UFH who are not within the therapeutic range in a timely manner are at greater risk of MACE and major/minor bleeding. Our study was not powered to detect these findings.
Strengths and Limitations
A significant limitation of this study was its small sample size; the study was not able to meet power for the primary outcome; it is unknown whether our study met power for nosocomial infections. The study also was not a powered review of other adverse events, such as thromboembolic complications, bleeding, and death. The study had an uneven number of patients, which made it more difficult to appropriately compare 2 patient populations; the study also did not include medians for patient characteristics and outcomes.
Due to this study’s time frame, the clinical pharmacy services at MEDVAMC were not as robust as they are now, which is the reason the decisions on which anticoagulant to use were primarily physician based. The use of TheraDoc to identify patients posed the risk of missing patients who may not have had the appropriate laboratory tests performed (ie, SCr). Patients on UFH had a reduced eGFR compared with that of enoxaparin, which may limit our extrapolation of enoxaparin’s use in end-stage renal disease. The reduced eGFR and higher number of dialysis patients in the UFH arm may have increased the occurrence of more labile INRs and bleeding outcomes. Patients on hemodialysis typically have more comorbidities and an increased risk of infection due to the frequent use of catheters and needles to access the bloodstream. In addition, the potential differences in catheter use and duration between groups were not identified. If these parameters were studied, the data collected may have helped better explain the reasoning for increased incidence of infection in the UFH arm.
Strengths of this study include a complex patient population with similar characteristics, distribution of ethnicities representative of the US population, patients at moderate-to-high thrombotic risk, the analysis of nosocomial infections, and the exclusion of patients with normal renal function or moderate CKD.
Conclusion
To our knowledge, this is the first study to compare periprocedural bridging outcomes and incidence of nosocomial infections in patients with AF and ACKD. This review provides new evidence that in this patient population, enoxaparin is a potential anticoagulant to reduce hospital LOS and hospital-acquired infections. Compared with UFH, bridging with enoxaparin reduced hospital LOS and anticoagulation time-to-discharge by 7 and 5 days, respectively, and decreased the incidence of nosocomial infections by 30%. Using the mean LOS per treating specialty for both arms, bridging 1 patient with AF with enoxaparin vs UFH can potentially lead to an estimated $40,000 (44%) reduction in total cost of hospitalization. Enoxaparin also had no numeric differences in mortality and adverse events (stroke/TIA, MI, VTE) vs that of UFH, but it is important to note that this study was not powered to find a significant difference in these outcomes. Due to the mean eGFR of patients on enoxaparin being 22.6 mL/min/1.73 m2 and only 1 in 5 having stage 5 CKD, at this time, we do not recommend enoxaparin for periprocedural use in stage 5 CKD or in patients on hemodialysis. Larger studies are needed, including randomized trials, in this patient population to further evaluate these outcomes and assess the use of enoxaparin in patients with ACKD.
1. Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2)(suppl):e326S-350S.
2. Douketis JD, Spyropoulos AC, Kaatz S, et al; BRIDGE Investigators. Perioperative bridging anticoagulation in patients with atrial fibrillation. N Engl J Med. 2015;373(9):823-833.
3. Hammerstingl C, Schmitz A, Fimmers R, Omran H. Bridging of chronic oral anticoagulation with enoxaparin in patients with atrial fibrillation: results from the prospective BRAVE registry. Cardiovasc Ther. 2009;27(4):230-238.
4. Dad T, Weiner DE. Stroke and chronic kidney disease: epidemiology, pathogenesis, and management across kidney disease stages. Semin Nephrol. 2015;35(4):311-322.
5. Wattanakit K, Cushman M. Chronic kidney disease and venous thromboembolism: epidemiology and mechanisms. Curr Opin Pulm Med. 2009;15(5):408-412.
6. Saltiel M. Dosing low molecular weight heparins in kidney disease. J Pharm Pract. 2010;23(3):205-209.
7. Spinler SA, Inverso SM, Cohen M, Goodman SG, Stringer KA, Antman EM; ESSENCE and TIMI 11B Investigators. Safety and efficacy of unfractionated heparin versus enoxaparin in patients who are obese and patients with severe renal impairment: analysis from the ESSENCE and TIMI 11B studies. Am Heart J. 2003;146(1):33-41.
8. Fox KA, Antman EM, Montalescot G, et al. The impact of renal dysfunction on outcomes in the ExTRACT-TIMI 25 trial. J Am Coll Cardiol. 2007;49(23):2249-2255.
9. Spyropoulos AC, Turpie AG, Dunn AS, et al; REGIMEN Investigators. Clinical outcomes with unfractionated heparin or low-molecular-weight heparin as bridging therapy in patients on long-term oral anticoagulants: the REGIMEN registry. J Thromb Haemost. 2006;4(6):1246-1252.
10. Amorosi SL, Tsilimingras K, Thompson D, Fanikos J, Weinstein MC, Goldhaber SZ. Cost analysis of “bridging therapy” with low-molecular-weight heparin versus unfractionated heparin during temporary interruption of chronic anticoagulation. Am J Cardiol. 2004;93(4):509-511.
11. Inker LA, Astor BC, Fox CH, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD. Am J Kidney Dis. 2014;63(5):713-735.
12. US Department of Veteran Affairs. Managerial Cost Accounting Financial User Support Reports: fiscal year 2018. https://www.herc.research.va.gov/include/page.asp?id=managerial-cost-accounting. [Source not verified.]
13. Doherty JU, Gluckman TJ, Hucker WJ, et al. 2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients With Nonvalvular Atrial Fibrillation: a report of the American College of Cardiology Clinical Expert Consensus Document Task Force. J Am Coll Cardiol. 2017;69(7):871-898.
14. Kearon C, Kahn SR, Agnelli G, et al. Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 suppl):454S-545S.
15. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994;47(11):1245-1251.
16. Lovenox [package insert]. Bridgewater, NJ: Sanofi-Aventis; December 2017.
17. Cruickshank MK, Levine MN, Hirsh J, Roberts R, Siguenza M. A standard heparin nomogram for the management of heparin therapy. Arch Intern Med. 1991;151(2):333-337.
18. Steinberg BA, Peterson ED, Kim S, et al; Outcomes Registry for Better Informed Treatment of Atrial Fibrillation Investigators and Patients. Use and outcomes associated with bridging during anticoagulation interruptions in patients with atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 2015;131(5):488-494.
19. Verheugt FW, Steinhubl SR, Hamon M, et al. Incidence, prognostic impact, and influence of antithrombotic therapy on access and nonaccess site bleeding in percutaneous coronary intervention. JACC Cardiovasc Interv. 2011;4(2):191-197.
20. Bijsterveld NR, Peters RJ, Murphy SA, Bernink PJ, Tijssen JG, Cohen M. Recurrent cardiac ischemic events early after discontinuation of short-term heparin treatment in acute coronary syndromes: results from the Thrombolysis in Myocardial Infarction (TIMI) 11B and Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events (ESSENCE) studies. J Am Coll Cardiol. 2003;42(12):2083-2089.
There has been a long-standing controversy in the use of parenteral anticoagulation for perioperative bridging in patients with atrial fibrillation (AF) pursuing elective surgery.1 The decision to bridge is dependent on the patient’s risk of thromboembolic complications and susceptibility to bleed.1 The BRIDGE trial showed noninferiority in rate of stroke and embolism events between low molecular weight heparins (LMWHs) and no perioperative bridging.2 However, according to the American College of Chest Physicians (CHEST) 2012 guidelines, patients in the BRIDGE trial would be deemed low risk for thromboembolic events displayed by a mean CHADS2 (congestive heart failure [CHF], hypertension, age, diabetes mellitus, and stroke/transient ischemic attack) score of 2.3. Also, the BRIDGE study and many others excluded patients with advanced forms of chronic kidney disease (CKD).2,3
Similar to patients with AF, patients with advanced CKD (ACKD, stage 4 and 5 CKD) have an increased risk of stroke and venous thromboembolism (VTE).4,5 Patients with AF and ACKD have not been adequately studied for perioperative anticoagulation bridging outcomes. Although unfractionated heparin (UFH) is preferred over LMWH in ACKD patients,enoxaparin can be used in this population.1,6 Enoxaparin 1 mg/kg once daily is approved by the US Food and Drug Administration (FDA) for use in patients with severe renal insufficiency defined as creatinine clearance (CrCl) < 30 mL/min. This dosage adjustment is subsequent to studies with enoxaparin 1 mg/kg twice daily that showed a significant increase in major and minor bleeding in severe renal-insufficient patients with CrCl < 30 mL/min vs patients with CrCl > 30 mL/min.7 When comparing the myocardial infarction (MI) outcomes of severe renal-insufficient patients in the ExTRACT-TIMI 25 trial, enoxaparin 1 mg/kg once daily had no significant difference in nonfatal major bleeding vs UFH.8 In patients without renal impairment (no documentation of kidney disease), bridging therapy with LMWH was completed more than UFH in < 24 hours of hospital stay and with similar rates of VTEs and major bleeding.9 In addition to its ability to be administered outpatient, enoxaparin has a more predictable pharmacokinetic profile, allowing for less monitoring and a lower incidence of heparin-induced thrombocytopenia (HIT) vs that of UFH.6
The Michael E. DeBakey Veteran Affairs Medical Center (MEDVAMC) in Houston, Texas, is one of the largest US Department of Veterans Affairs (VA) hospitals in the US, managing > 150,000 veterans in Southeast Texas and other southern states. As a referral center for traveling patients, it is crucial that MEDVAMC decrease hospital length of stay (LOS) to increase space for incoming patients. Reducing LOS also reduces costs and may have a correlation with decreasing the incidence of nosocomial infections. Because of its significance to this facility, hospital LOS is an appropriate primary outcome for this study.
To our knowledge, bridging outcomes between LMWH and UFH in patients with AF and ACKD have never been studied. We hypothesized that using enoxaparin instead of heparin for periprocedural management would result in decreased hospital LOS, leading to a lower economic burden and lower incidence of nosocomial infections with no significant differences in major and minor bleeding and thromboembolic complications.10
Methods
This study was a single-center, retrospective chart review of adult patients from January 2008 to September 2017. The review was conducted at MEDVAMC and was approved by the research and development committee and by the Baylor College of Medicine Institutional Review Board. Formal consent was not required.
Included patients were aged ≥ 18 years with diagnoses of AF or atrial flutter and ACKD as recognized by a glomerular filtration rate (eGFR) of < 30 mL/min/1.73 m2 as calculated by use of the Modification of Diet in Renal Disease Study (MDRD) equation.11 Patients must have previously been on warfarin and required temporary interruption of warfarin for an elective procedure. During the interruption of warfarin therapy, a requirement was set for patients to be on periprocedural anticoagulation with subcutaneous (SC) enoxaparin 1 mg/kg daily or continuous IV heparin per MEDVAMC heparin protocol. Patients were excluded if they had experienced major bleeding in the 6 weeks prior to the elective procedure, had current thrombocytopenia (platelet count < 100 × 109/L), or had a history of heparin-induced thrombocytopenia (HIT) or a heparin allergy.
This patient population was identified using TheraDoc Clinical Surveillance Software System (Charlotte, NC), which has prebuilt alert reviews for anticoagulation medications, including enoxaparin and heparin. An alert for patients on enoxaparin with serum creatinine (SCr) > 1.5 mg/dL was used to screen patients who met the inclusion criteria. A second alert identified patients on heparin. The VA Computerized Patient Record System (CPRS) was used to collect patient data.
Economic Analysis
An economic analysis was conducted using data from the VA Managerial Cost Accounting Reports. Data on the national average cost per bed day was used for the purpose of extrapolating this information to multiple VA institutions.12 National average cost per day was determined by dividing the total cost by the number of bed days for the identified treating specialty during the fiscal period of 2018. Average cost per day data included costs for bed day, surgery, radiology services, laboratory tests, pharmacy services, treatment location (ie, intensive care units [ICUs]) and all other costs associated with an inpatient stay. A cost analysis was performed using this average cost per bed day and the mean LOS between enoxaparin and UFH for each treating specialty. The major outcome of the cost analysis was the total cost per average inpatient stay. The national average cost per bed day for each treating specialty was multiplied by the average LOS found for each treating specialty in this study; the sum of all the average costs per inpatient stay for the treating specialties resulted in the total cost per average inpatient stay. Permission to use these data was granted by the Pharmacy and Critical Care Services at MEDVAMC.
Patient Demographics and Characteristics
Data were collected on patient demographics (Table 1). Nosocomial infections, stroke/transient ischemic attack, MI, VTE, major and minor bleeding, and death are defined in Table 2.
The primary outcome of the study was hospital LOS. The study was powered at 90% for α = .05, which gives a required study population of 114 (1:1 enrollment ratio) patients to determine a statistically significant difference in hospital stay. This sample size was calculated using the mean hospital LOS (the primary objective) in the REGIMEN registry for LMWH (4.6 days) and UFH (10.3 days).9 To our knowledge, the incidence of nosocomial infections (a secondary outcome) has not been studied in this patient population; therefore, there was no basis to assess an appropriate sample size to find a difference in this outcome. Furthermore, the goal was to collect as many patients as possible to best assess this variable. Because of an expected high exclusion rate, 504 patients were reviewed to target a sample size of 120 patients. Due to the single-center nature of this review, the secondary outcomes of thromboembolic complications and major and minor bleeding were expected to be underpowered.
The final analysis compared the enoxaparin arm with the UFH arm. Univariate differences between the treatment groups were compared using the Fisher exact test for categorical variables. Demographic data and other continuous variables were analyzed by an unpaired t test to compare means between the 2 arms. Outcomes and characteristics were deemed statistically significant when α (P value) was < .05. All P values reported were 2-tailed with a 95% CI. No statistical analysis was performed for the cost differences (based on LOS per treating specialty) in the 2 treatment arms. Statistical analyses were completed by utilizing GraphPad Software (San Diego, CA).
Results
In total, 50 patients were analyzed in the study. There were 36 patients bridged with IV UFH at a concentration of 25,000 U/250 mL with an initial infusion rate of 12 U/kg/h. For the other arm, 14 patients were anticoagulated with renally dosed enoxaparin 1 mg/kg/d with an average daily dose of 89.3 mg; the mean actual body weight in this group was 90.9 mg (correlates with enoxaparin daily dose). Physicians of the primary team decided which parenteral anticoagulant to use. The difference in mean duration of inpatient parental anticoagulation between both groups was not statistically significant: enoxaparin at 7.1 days and UFH at 9.6 days (P = .19). Patients in the enoxaparin arm were off warfarin therapy for an average of 6.0 days vs 7.5 days for the UFH group (P = .29). The duration of outpatient anticoagulation with enoxaparin was not analyzed in this study.
Patient and Procedure Characteristics
All patients had AF or atrial flutter with 86% of patients (n = 43) having a CHADS2 > 2 and 48% (n = 29) having a CHA2DS2VASc > 4. Overall, the mean age was 71.3 years with similarities in ethnicity distribution. Patients had multiple comorbidities as shown by a mean Charlson Comorbidity Index (CCI) of 7.7 and an increased risk of bleeding as evidenced by 98% (n = 48) of patients having a HAS-BLED score of ≥ 3. A greater percentage of patients bridged with enoxaparin had DM, history of stroke and MI, and a heart valve, whereas UFH patients were more likely to be in stage 5 CKD (eGFR < 15 mL/min/1.73m2) with a significantly lower mean eGFR (16.76 vs 22.64, P = .03). Furthermore, there were more patients on hemodialysis in the UFH (50%) arm vs enoxaparin (21%) arm and a lower mean CrCl with UFH (20.1 mL/min) compared with enoxaparin (24.9 mL/min); however, the differences in hemodialysis and mean CrCl were not statistically significant. There were no patients on peritoneal dialysis in this review.
Procedure Characteristics
The average Revised Cardiac Risk Index (RCRI) score was about 3, indicating that these patients were at a Class IV risk (11%) of having a perioperative cardiac event (Table 3). Nineteen patients (38%) elected for a major surgery with all but 1 of the surgeries (major or minor) being invasive. The average length of surgery was 1.2 hours, and patients were more likely to undergo cardiothoracic procedures (38%). There were 2 out of 14 (14%) patients on enoxaparin who were able to have surgery as an outpatient; whereas this did not occur in patients on UFH. The procedures completed for these patients were a colostomy (minor surgery) and arteriovenous graft repair (major surgery). There were no statistically significant differences regarding types of procedures between the 2 arms.
Outcomes
The primary outcome of this study, hospital LOS, differed significantly in the enoxaparin arm vs UFH: 10.2 days vs 17.5 days, P = .04 (Table 4). The time-to-discharge from initiation of parenteral anticoagulation was significantly reduced with enoxaparin (7.1 days) compared with UFH (11.9 days); P = .04. Although also reduced in the enoxaparin arm, ICU LOS did not show statistical significance (1.1 days vs 4.0 days, P = .09).
About 36% (n = 18) of patients in this study acquired an infection during hospitalization for elective surgery. The most common microorganism and site of infection were Enterococcus species and urinary tract, respectively (Table 5). Nearly half (44%, n = 16) of the patients in the UFH group had a nosocomial infection vs 14% (n = 2) of enoxaparin-bridged patients with a difference approaching significance; P = .056. Both patients in the enoxaparin group had the urinary tract as the primary source of infection; 1 of these patients had a urologic procedure.
Major bleeding occurred in 7% (n = 1) of enoxaparin patients vs 22% (n = 8) in the UFH arm, but this was not found to be statistically significant (P = .41). Minor bleeding was similar between enoxaparin and UFH arms (14% vs 19%, P = .99). Regarding thromboembolic complications, the enoxaparin group (0%) had a numerical reduction compared to UFH (11%) with VTE (n = 4) being the only occurrence of the composite outcome (P = .57). There were 4 deaths within 30 days posthospitalization—all were from the UFH group (P = .57). Due to the small sample size of this study, these outcomes (bleeding and thrombotic events) were not powered to detect a statistically significant difference.
Economic Analysis
The average cost differences (Table 6) of hospitalization between enoxaparin and UFH were calculated using the average LOS per treating specialty multiplied by the national average cost of the MCO for an inpatient bed day in 2018.12 The treating specialty with the longest average LOS in the enoxaparin arm was thoracic (4.7 days). The UFH arm also had a large LOS (average days) for the thoracic specialty (6.4 days); however, the vascular specialty (6.7 days) had the longest average LOS in this group. Due to a mean LOS of 10.2 days in the enoxaparin arm, which was further stratified by treating specialty, the total cost per average inpatient stay was calculated as $51,710. On the other hand, patients in the UFH arm had a total cost per average inpatient stay of $92,848.
Monitoring
Anti-factor Xa levels for LMWH monitoring were not analyzed in this study due to a lack of values collected; only 1 patient had an anti-factor Xa level checked during this time frame. Infusion rates of UFH were adjusted based on aPTT levels collected per MEDVAMC inpatient anticoagulation protocol. The average percentage of aPTT in therapeutic range was 46.3% and the mean time-to-therapeutic range (SD) was about 2.4 (1.3) days. Due to this study’s retrospective nature, there were inconsistencies with availability of documentation of UFH infusion rates. For this reason, these values were not analyzed further.
Discussion
In 2017, the American College of Cardiology published the Periprocedural Anticoagulation Expert Consensus Pathway, which recommends for patients with AF at low risk (CHA2DS2VASc 1-4) of thromboembolism to not be bridged (unless patient had a prior VTE or stroke/TIA).13 Nearly half the patients in this study, were classified as moderate-to-high thrombotic risk as evidenced by a CHA2DS2VASc > 4 with a mean score of 4.8. Due to this study’s retrospective design from 2008 to 2017, many of the clinicians may have referenced the 2008 CHEST antithrombotic guidelines when making the decision to bridge patients; these guidelines and the previous MEDVAMC anticoagulation protocol recommend bridging patients with AF with CHADS2 > 2 (moderate-to-high thrombotic risk) in which all but 1 of the patients in this study met criteria.1,14 In contrast to the landmark BRIDGE trial, the mean CHADS2 score in this study was 3.6; this is an indication that our patient population was of individuals at an increased risk of stroke and embolism.
In addition to thromboembolic complications, patients in the current study also were at increased risk of clinically relevant bleeding with a mean HAS-BLED score of 4.1 and nearly all patients having a score > 3. The complexity of the veteran population also was displayed by this study’s mean CCI (7.7) and RCRI (3.0) indicating a 0% estimated 10-year survival and a 11% increase in having a perioperative cardiac event, respectively. A mean CCI of 7.7 is associated with a 13.3 relative risk of death within 6 years postoperation.15 All patients had a diagnosis of hypertension, and > 75% had this diagnosis complicated by DM. In addition, this patient population was of those with extensive cardiovascular disease or increased risk, which makes for a clinically relevant application of patients who would require periprocedural bridging.
Another positive aspect of this study is that all the baseline characteristics, apart from renal function, were similar between arms, helping to strengthen the ability to adequately compare the 2 bridging modalities. Our assumption for the reasoning that more stage 5 CKD and dialysis patients were anticoagulated with UFH vs enoxaparin is a result of concern for an increased risk of bleeding with a medication that is renally cleared 30% less in CrCl < 30 mL/min.16 Although, enoxaparin 1 mg/kg/d is FDA approved as a therapeutic anticoagulant option, clinicians at MEDVAMC likely had reservations about its use in end-stage CKD patients. Unlike many studies, including the BRIDGE trial, patients with ACKD were not excluded from this trial, and the outcomes with enoxaparin are available for interpretation.
To no surprise, for patients included in this study, enoxaparin use led to shorter hospital LOS, reduced ICU LOS, and a quicker time-to-discharge from initiation. This is credited to the 100% bioavailability of SC enoxaparin in conjunction with its means to be a therapeutic option as an outpatient.16 Unlike IV UFH, patients requiring bridging can be discharged on SC injections of enoxaparin until a therapeutic INR is maintained with warfarin.The duration of hospital LOS in both arms were longer in this study compared with that of other studies.9 This may be due to clinicians being more cautious with renal insufficient patients, and the patients included in this study had multiple comorbidities. According to an economic analysis performed by Amorosi and colleagues in 2004, bridging with enoxaparin instead of UFH can save up to $3,733 per patient and reduce bridging costs by 63% to 85% driven primarily by decreased hospital LOS.10
Economic Outcome
In our study, we conducted a cost analysis using national VA data that indicated a $41,138 or 44% reduction in total cost per average inpatient stay when bridging 1 patient with enoxaparin vs UFH. The benefit of this cost analysis is that it reflects direct costs at VA institutions nationally; this will allow these data to be useful for practitioners at MEDVAMC and other VA hospitals. Stratifying the costs by treating specialty instead of treatment location minimized skewing of the data as there were some patients with long LOS in the ICU. No patients in the enoxaparin arm were treated in otolaryngology, which may have skewed the data. The data included direct costs for beds as well as costs for multiple services, such as procedures, pharmacy, nursing, laboratory tests, and imaging. Unlike the Amorosi study, our review did not include acquisition costs for enoxaparin syringes and bags of UFH or laboratory costs for aPTT and anti-factor Xa levels in part because of the data source and the difficulty calculating costs over a 10-year span.
Patients in the enoxaparin arm had a trend toward fewer occurrences of hospital-acquired infections than did those in the UFH arm, which we believe is due to a decreased LOS (in both total hospital and ICU days) and fewer blood draws needed for monitoring. This also may be attributed to a longer mean duration of surgery in the UFH arm (1.3 hours) vs enoxaparin (0.9 hours). The percentage of patients with procedures ≥ 45 minutes and the types of procedures between both arms were similar. However, these outcomes were not statistically significant. In addition, elderly males who are hospitalized may require a catheter (due to urinary retention), and catheter-associated urinary tract infection (CAUTI) is one of the highest reported infections in acute care hospitals in the US. This is in line with our patient population and may be a supplementary reason for the increase in infection incidence with UFH. Though, whether urinary catheters were used in these patients was not evaluated in this study.
Despite being at an increased risk of experiencing a major adverse cardiovascular event (MACE), no patients in either arm had a stroke/TIA or MI within 30 days postprocedure. The only occurrences documented were VTEs, which happened only in 4 patients on UFH. Four people died in this study, solely in the UFH arm. The incidence of thromboembolic complications and death along with major and minor bleeding cannot be deduced as meaningful as this study was underpowered for these outcomes. Despite anti-factor Xa monitoring being recommended in ACKD patients on enoxaparin, this monitoring was not routinely performed in this study. Another limitation was the inability to adequately assess the appropriateness of nurse-adjusted UFH infusion rates largely due to the retrospective nature of this study. The variability of aPTT percentage in therapeutic range and time-to-therapeutic range reported was indicative of the difficulties of monitoring for the safety and efficacy of UFH.
In 1991, Cruickshank and colleagues conducted a study in which a standard nomogram (similar to the MEDVAMC nomogram) for the adjustment of IV heparin was implemented at a single hospital.17 The success rate (aPTT percentage in therapeutic range) was 59.4% and average time-to-therapeutic range was about 1 day. The success rate (46.3%) and time-to-therapeutic range (2.4 days) in our study were lower and longer, respectively, than was expected. One potential reason for this discrepancy could be the differences in indication as the patients in Cruickshank and colleagues were being treated for VTE, whereas patients in our study had AF or atrial flutter. Also, there were inconsistencies in the availability of documentation of monitoring parameters for heparin due to the study time frame and retrospective design. Patients on UFH who are not within the therapeutic range in a timely manner are at greater risk of MACE and major/minor bleeding. Our study was not powered to detect these findings.
Strengths and Limitations
A significant limitation of this study was its small sample size; the study was not able to meet power for the primary outcome; it is unknown whether our study met power for nosocomial infections. The study also was not a powered review of other adverse events, such as thromboembolic complications, bleeding, and death. The study had an uneven number of patients, which made it more difficult to appropriately compare 2 patient populations; the study also did not include medians for patient characteristics and outcomes.
Due to this study’s time frame, the clinical pharmacy services at MEDVAMC were not as robust as they are now, which is the reason the decisions on which anticoagulant to use were primarily physician based. The use of TheraDoc to identify patients posed the risk of missing patients who may not have had the appropriate laboratory tests performed (ie, SCr). Patients on UFH had a reduced eGFR compared with that of enoxaparin, which may limit our extrapolation of enoxaparin’s use in end-stage renal disease. The reduced eGFR and higher number of dialysis patients in the UFH arm may have increased the occurrence of more labile INRs and bleeding outcomes. Patients on hemodialysis typically have more comorbidities and an increased risk of infection due to the frequent use of catheters and needles to access the bloodstream. In addition, the potential differences in catheter use and duration between groups were not identified. If these parameters were studied, the data collected may have helped better explain the reasoning for increased incidence of infection in the UFH arm.
Strengths of this study include a complex patient population with similar characteristics, distribution of ethnicities representative of the US population, patients at moderate-to-high thrombotic risk, the analysis of nosocomial infections, and the exclusion of patients with normal renal function or moderate CKD.
Conclusion
To our knowledge, this is the first study to compare periprocedural bridging outcomes and incidence of nosocomial infections in patients with AF and ACKD. This review provides new evidence that in this patient population, enoxaparin is a potential anticoagulant to reduce hospital LOS and hospital-acquired infections. Compared with UFH, bridging with enoxaparin reduced hospital LOS and anticoagulation time-to-discharge by 7 and 5 days, respectively, and decreased the incidence of nosocomial infections by 30%. Using the mean LOS per treating specialty for both arms, bridging 1 patient with AF with enoxaparin vs UFH can potentially lead to an estimated $40,000 (44%) reduction in total cost of hospitalization. Enoxaparin also had no numeric differences in mortality and adverse events (stroke/TIA, MI, VTE) vs that of UFH, but it is important to note that this study was not powered to find a significant difference in these outcomes. Due to the mean eGFR of patients on enoxaparin being 22.6 mL/min/1.73 m2 and only 1 in 5 having stage 5 CKD, at this time, we do not recommend enoxaparin for periprocedural use in stage 5 CKD or in patients on hemodialysis. Larger studies are needed, including randomized trials, in this patient population to further evaluate these outcomes and assess the use of enoxaparin in patients with ACKD.
There has been a long-standing controversy in the use of parenteral anticoagulation for perioperative bridging in patients with atrial fibrillation (AF) pursuing elective surgery.1 The decision to bridge is dependent on the patient’s risk of thromboembolic complications and susceptibility to bleed.1 The BRIDGE trial showed noninferiority in rate of stroke and embolism events between low molecular weight heparins (LMWHs) and no perioperative bridging.2 However, according to the American College of Chest Physicians (CHEST) 2012 guidelines, patients in the BRIDGE trial would be deemed low risk for thromboembolic events displayed by a mean CHADS2 (congestive heart failure [CHF], hypertension, age, diabetes mellitus, and stroke/transient ischemic attack) score of 2.3. Also, the BRIDGE study and many others excluded patients with advanced forms of chronic kidney disease (CKD).2,3
Similar to patients with AF, patients with advanced CKD (ACKD, stage 4 and 5 CKD) have an increased risk of stroke and venous thromboembolism (VTE).4,5 Patients with AF and ACKD have not been adequately studied for perioperative anticoagulation bridging outcomes. Although unfractionated heparin (UFH) is preferred over LMWH in ACKD patients,enoxaparin can be used in this population.1,6 Enoxaparin 1 mg/kg once daily is approved by the US Food and Drug Administration (FDA) for use in patients with severe renal insufficiency defined as creatinine clearance (CrCl) < 30 mL/min. This dosage adjustment is subsequent to studies with enoxaparin 1 mg/kg twice daily that showed a significant increase in major and minor bleeding in severe renal-insufficient patients with CrCl < 30 mL/min vs patients with CrCl > 30 mL/min.7 When comparing the myocardial infarction (MI) outcomes of severe renal-insufficient patients in the ExTRACT-TIMI 25 trial, enoxaparin 1 mg/kg once daily had no significant difference in nonfatal major bleeding vs UFH.8 In patients without renal impairment (no documentation of kidney disease), bridging therapy with LMWH was completed more than UFH in < 24 hours of hospital stay and with similar rates of VTEs and major bleeding.9 In addition to its ability to be administered outpatient, enoxaparin has a more predictable pharmacokinetic profile, allowing for less monitoring and a lower incidence of heparin-induced thrombocytopenia (HIT) vs that of UFH.6
The Michael E. DeBakey Veteran Affairs Medical Center (MEDVAMC) in Houston, Texas, is one of the largest US Department of Veterans Affairs (VA) hospitals in the US, managing > 150,000 veterans in Southeast Texas and other southern states. As a referral center for traveling patients, it is crucial that MEDVAMC decrease hospital length of stay (LOS) to increase space for incoming patients. Reducing LOS also reduces costs and may have a correlation with decreasing the incidence of nosocomial infections. Because of its significance to this facility, hospital LOS is an appropriate primary outcome for this study.
To our knowledge, bridging outcomes between LMWH and UFH in patients with AF and ACKD have never been studied. We hypothesized that using enoxaparin instead of heparin for periprocedural management would result in decreased hospital LOS, leading to a lower economic burden and lower incidence of nosocomial infections with no significant differences in major and minor bleeding and thromboembolic complications.10
Methods
This study was a single-center, retrospective chart review of adult patients from January 2008 to September 2017. The review was conducted at MEDVAMC and was approved by the research and development committee and by the Baylor College of Medicine Institutional Review Board. Formal consent was not required.
Included patients were aged ≥ 18 years with diagnoses of AF or atrial flutter and ACKD as recognized by a glomerular filtration rate (eGFR) of < 30 mL/min/1.73 m2 as calculated by use of the Modification of Diet in Renal Disease Study (MDRD) equation.11 Patients must have previously been on warfarin and required temporary interruption of warfarin for an elective procedure. During the interruption of warfarin therapy, a requirement was set for patients to be on periprocedural anticoagulation with subcutaneous (SC) enoxaparin 1 mg/kg daily or continuous IV heparin per MEDVAMC heparin protocol. Patients were excluded if they had experienced major bleeding in the 6 weeks prior to the elective procedure, had current thrombocytopenia (platelet count < 100 × 109/L), or had a history of heparin-induced thrombocytopenia (HIT) or a heparin allergy.
This patient population was identified using TheraDoc Clinical Surveillance Software System (Charlotte, NC), which has prebuilt alert reviews for anticoagulation medications, including enoxaparin and heparin. An alert for patients on enoxaparin with serum creatinine (SCr) > 1.5 mg/dL was used to screen patients who met the inclusion criteria. A second alert identified patients on heparin. The VA Computerized Patient Record System (CPRS) was used to collect patient data.
Economic Analysis
An economic analysis was conducted using data from the VA Managerial Cost Accounting Reports. Data on the national average cost per bed day was used for the purpose of extrapolating this information to multiple VA institutions.12 National average cost per day was determined by dividing the total cost by the number of bed days for the identified treating specialty during the fiscal period of 2018. Average cost per day data included costs for bed day, surgery, radiology services, laboratory tests, pharmacy services, treatment location (ie, intensive care units [ICUs]) and all other costs associated with an inpatient stay. A cost analysis was performed using this average cost per bed day and the mean LOS between enoxaparin and UFH for each treating specialty. The major outcome of the cost analysis was the total cost per average inpatient stay. The national average cost per bed day for each treating specialty was multiplied by the average LOS found for each treating specialty in this study; the sum of all the average costs per inpatient stay for the treating specialties resulted in the total cost per average inpatient stay. Permission to use these data was granted by the Pharmacy and Critical Care Services at MEDVAMC.
Patient Demographics and Characteristics
Data were collected on patient demographics (Table 1). Nosocomial infections, stroke/transient ischemic attack, MI, VTE, major and minor bleeding, and death are defined in Table 2.
The primary outcome of the study was hospital LOS. The study was powered at 90% for α = .05, which gives a required study population of 114 (1:1 enrollment ratio) patients to determine a statistically significant difference in hospital stay. This sample size was calculated using the mean hospital LOS (the primary objective) in the REGIMEN registry for LMWH (4.6 days) and UFH (10.3 days).9 To our knowledge, the incidence of nosocomial infections (a secondary outcome) has not been studied in this patient population; therefore, there was no basis to assess an appropriate sample size to find a difference in this outcome. Furthermore, the goal was to collect as many patients as possible to best assess this variable. Because of an expected high exclusion rate, 504 patients were reviewed to target a sample size of 120 patients. Due to the single-center nature of this review, the secondary outcomes of thromboembolic complications and major and minor bleeding were expected to be underpowered.
The final analysis compared the enoxaparin arm with the UFH arm. Univariate differences between the treatment groups were compared using the Fisher exact test for categorical variables. Demographic data and other continuous variables were analyzed by an unpaired t test to compare means between the 2 arms. Outcomes and characteristics were deemed statistically significant when α (P value) was < .05. All P values reported were 2-tailed with a 95% CI. No statistical analysis was performed for the cost differences (based on LOS per treating specialty) in the 2 treatment arms. Statistical analyses were completed by utilizing GraphPad Software (San Diego, CA).
Results
In total, 50 patients were analyzed in the study. There were 36 patients bridged with IV UFH at a concentration of 25,000 U/250 mL with an initial infusion rate of 12 U/kg/h. For the other arm, 14 patients were anticoagulated with renally dosed enoxaparin 1 mg/kg/d with an average daily dose of 89.3 mg; the mean actual body weight in this group was 90.9 mg (correlates with enoxaparin daily dose). Physicians of the primary team decided which parenteral anticoagulant to use. The difference in mean duration of inpatient parental anticoagulation between both groups was not statistically significant: enoxaparin at 7.1 days and UFH at 9.6 days (P = .19). Patients in the enoxaparin arm were off warfarin therapy for an average of 6.0 days vs 7.5 days for the UFH group (P = .29). The duration of outpatient anticoagulation with enoxaparin was not analyzed in this study.
Patient and Procedure Characteristics
All patients had AF or atrial flutter with 86% of patients (n = 43) having a CHADS2 > 2 and 48% (n = 29) having a CHA2DS2VASc > 4. Overall, the mean age was 71.3 years with similarities in ethnicity distribution. Patients had multiple comorbidities as shown by a mean Charlson Comorbidity Index (CCI) of 7.7 and an increased risk of bleeding as evidenced by 98% (n = 48) of patients having a HAS-BLED score of ≥ 3. A greater percentage of patients bridged with enoxaparin had DM, history of stroke and MI, and a heart valve, whereas UFH patients were more likely to be in stage 5 CKD (eGFR < 15 mL/min/1.73m2) with a significantly lower mean eGFR (16.76 vs 22.64, P = .03). Furthermore, there were more patients on hemodialysis in the UFH (50%) arm vs enoxaparin (21%) arm and a lower mean CrCl with UFH (20.1 mL/min) compared with enoxaparin (24.9 mL/min); however, the differences in hemodialysis and mean CrCl were not statistically significant. There were no patients on peritoneal dialysis in this review.
Procedure Characteristics
The average Revised Cardiac Risk Index (RCRI) score was about 3, indicating that these patients were at a Class IV risk (11%) of having a perioperative cardiac event (Table 3). Nineteen patients (38%) elected for a major surgery with all but 1 of the surgeries (major or minor) being invasive. The average length of surgery was 1.2 hours, and patients were more likely to undergo cardiothoracic procedures (38%). There were 2 out of 14 (14%) patients on enoxaparin who were able to have surgery as an outpatient; whereas this did not occur in patients on UFH. The procedures completed for these patients were a colostomy (minor surgery) and arteriovenous graft repair (major surgery). There were no statistically significant differences regarding types of procedures between the 2 arms.
Outcomes
The primary outcome of this study, hospital LOS, differed significantly in the enoxaparin arm vs UFH: 10.2 days vs 17.5 days, P = .04 (Table 4). The time-to-discharge from initiation of parenteral anticoagulation was significantly reduced with enoxaparin (7.1 days) compared with UFH (11.9 days); P = .04. Although also reduced in the enoxaparin arm, ICU LOS did not show statistical significance (1.1 days vs 4.0 days, P = .09).
About 36% (n = 18) of patients in this study acquired an infection during hospitalization for elective surgery. The most common microorganism and site of infection were Enterococcus species and urinary tract, respectively (Table 5). Nearly half (44%, n = 16) of the patients in the UFH group had a nosocomial infection vs 14% (n = 2) of enoxaparin-bridged patients with a difference approaching significance; P = .056. Both patients in the enoxaparin group had the urinary tract as the primary source of infection; 1 of these patients had a urologic procedure.
Major bleeding occurred in 7% (n = 1) of enoxaparin patients vs 22% (n = 8) in the UFH arm, but this was not found to be statistically significant (P = .41). Minor bleeding was similar between enoxaparin and UFH arms (14% vs 19%, P = .99). Regarding thromboembolic complications, the enoxaparin group (0%) had a numerical reduction compared to UFH (11%) with VTE (n = 4) being the only occurrence of the composite outcome (P = .57). There were 4 deaths within 30 days posthospitalization—all were from the UFH group (P = .57). Due to the small sample size of this study, these outcomes (bleeding and thrombotic events) were not powered to detect a statistically significant difference.
Economic Analysis
The average cost differences (Table 6) of hospitalization between enoxaparin and UFH were calculated using the average LOS per treating specialty multiplied by the national average cost of the MCO for an inpatient bed day in 2018.12 The treating specialty with the longest average LOS in the enoxaparin arm was thoracic (4.7 days). The UFH arm also had a large LOS (average days) for the thoracic specialty (6.4 days); however, the vascular specialty (6.7 days) had the longest average LOS in this group. Due to a mean LOS of 10.2 days in the enoxaparin arm, which was further stratified by treating specialty, the total cost per average inpatient stay was calculated as $51,710. On the other hand, patients in the UFH arm had a total cost per average inpatient stay of $92,848.
Monitoring
Anti-factor Xa levels for LMWH monitoring were not analyzed in this study due to a lack of values collected; only 1 patient had an anti-factor Xa level checked during this time frame. Infusion rates of UFH were adjusted based on aPTT levels collected per MEDVAMC inpatient anticoagulation protocol. The average percentage of aPTT in therapeutic range was 46.3% and the mean time-to-therapeutic range (SD) was about 2.4 (1.3) days. Due to this study’s retrospective nature, there were inconsistencies with availability of documentation of UFH infusion rates. For this reason, these values were not analyzed further.
Discussion
In 2017, the American College of Cardiology published the Periprocedural Anticoagulation Expert Consensus Pathway, which recommends for patients with AF at low risk (CHA2DS2VASc 1-4) of thromboembolism to not be bridged (unless patient had a prior VTE or stroke/TIA).13 Nearly half the patients in this study, were classified as moderate-to-high thrombotic risk as evidenced by a CHA2DS2VASc > 4 with a mean score of 4.8. Due to this study’s retrospective design from 2008 to 2017, many of the clinicians may have referenced the 2008 CHEST antithrombotic guidelines when making the decision to bridge patients; these guidelines and the previous MEDVAMC anticoagulation protocol recommend bridging patients with AF with CHADS2 > 2 (moderate-to-high thrombotic risk) in which all but 1 of the patients in this study met criteria.1,14 In contrast to the landmark BRIDGE trial, the mean CHADS2 score in this study was 3.6; this is an indication that our patient population was of individuals at an increased risk of stroke and embolism.
In addition to thromboembolic complications, patients in the current study also were at increased risk of clinically relevant bleeding with a mean HAS-BLED score of 4.1 and nearly all patients having a score > 3. The complexity of the veteran population also was displayed by this study’s mean CCI (7.7) and RCRI (3.0) indicating a 0% estimated 10-year survival and a 11% increase in having a perioperative cardiac event, respectively. A mean CCI of 7.7 is associated with a 13.3 relative risk of death within 6 years postoperation.15 All patients had a diagnosis of hypertension, and > 75% had this diagnosis complicated by DM. In addition, this patient population was of those with extensive cardiovascular disease or increased risk, which makes for a clinically relevant application of patients who would require periprocedural bridging.
Another positive aspect of this study is that all the baseline characteristics, apart from renal function, were similar between arms, helping to strengthen the ability to adequately compare the 2 bridging modalities. Our assumption for the reasoning that more stage 5 CKD and dialysis patients were anticoagulated with UFH vs enoxaparin is a result of concern for an increased risk of bleeding with a medication that is renally cleared 30% less in CrCl < 30 mL/min.16 Although, enoxaparin 1 mg/kg/d is FDA approved as a therapeutic anticoagulant option, clinicians at MEDVAMC likely had reservations about its use in end-stage CKD patients. Unlike many studies, including the BRIDGE trial, patients with ACKD were not excluded from this trial, and the outcomes with enoxaparin are available for interpretation.
To no surprise, for patients included in this study, enoxaparin use led to shorter hospital LOS, reduced ICU LOS, and a quicker time-to-discharge from initiation. This is credited to the 100% bioavailability of SC enoxaparin in conjunction with its means to be a therapeutic option as an outpatient.16 Unlike IV UFH, patients requiring bridging can be discharged on SC injections of enoxaparin until a therapeutic INR is maintained with warfarin.The duration of hospital LOS in both arms were longer in this study compared with that of other studies.9 This may be due to clinicians being more cautious with renal insufficient patients, and the patients included in this study had multiple comorbidities. According to an economic analysis performed by Amorosi and colleagues in 2004, bridging with enoxaparin instead of UFH can save up to $3,733 per patient and reduce bridging costs by 63% to 85% driven primarily by decreased hospital LOS.10
Economic Outcome
In our study, we conducted a cost analysis using national VA data that indicated a $41,138 or 44% reduction in total cost per average inpatient stay when bridging 1 patient with enoxaparin vs UFH. The benefit of this cost analysis is that it reflects direct costs at VA institutions nationally; this will allow these data to be useful for practitioners at MEDVAMC and other VA hospitals. Stratifying the costs by treating specialty instead of treatment location minimized skewing of the data as there were some patients with long LOS in the ICU. No patients in the enoxaparin arm were treated in otolaryngology, which may have skewed the data. The data included direct costs for beds as well as costs for multiple services, such as procedures, pharmacy, nursing, laboratory tests, and imaging. Unlike the Amorosi study, our review did not include acquisition costs for enoxaparin syringes and bags of UFH or laboratory costs for aPTT and anti-factor Xa levels in part because of the data source and the difficulty calculating costs over a 10-year span.
Patients in the enoxaparin arm had a trend toward fewer occurrences of hospital-acquired infections than did those in the UFH arm, which we believe is due to a decreased LOS (in both total hospital and ICU days) and fewer blood draws needed for monitoring. This also may be attributed to a longer mean duration of surgery in the UFH arm (1.3 hours) vs enoxaparin (0.9 hours). The percentage of patients with procedures ≥ 45 minutes and the types of procedures between both arms were similar. However, these outcomes were not statistically significant. In addition, elderly males who are hospitalized may require a catheter (due to urinary retention), and catheter-associated urinary tract infection (CAUTI) is one of the highest reported infections in acute care hospitals in the US. This is in line with our patient population and may be a supplementary reason for the increase in infection incidence with UFH. Though, whether urinary catheters were used in these patients was not evaluated in this study.
Despite being at an increased risk of experiencing a major adverse cardiovascular event (MACE), no patients in either arm had a stroke/TIA or MI within 30 days postprocedure. The only occurrences documented were VTEs, which happened only in 4 patients on UFH. Four people died in this study, solely in the UFH arm. The incidence of thromboembolic complications and death along with major and minor bleeding cannot be deduced as meaningful as this study was underpowered for these outcomes. Despite anti-factor Xa monitoring being recommended in ACKD patients on enoxaparin, this monitoring was not routinely performed in this study. Another limitation was the inability to adequately assess the appropriateness of nurse-adjusted UFH infusion rates largely due to the retrospective nature of this study. The variability of aPTT percentage in therapeutic range and time-to-therapeutic range reported was indicative of the difficulties of monitoring for the safety and efficacy of UFH.
In 1991, Cruickshank and colleagues conducted a study in which a standard nomogram (similar to the MEDVAMC nomogram) for the adjustment of IV heparin was implemented at a single hospital.17 The success rate (aPTT percentage in therapeutic range) was 59.4% and average time-to-therapeutic range was about 1 day. The success rate (46.3%) and time-to-therapeutic range (2.4 days) in our study were lower and longer, respectively, than was expected. One potential reason for this discrepancy could be the differences in indication as the patients in Cruickshank and colleagues were being treated for VTE, whereas patients in our study had AF or atrial flutter. Also, there were inconsistencies in the availability of documentation of monitoring parameters for heparin due to the study time frame and retrospective design. Patients on UFH who are not within the therapeutic range in a timely manner are at greater risk of MACE and major/minor bleeding. Our study was not powered to detect these findings.
Strengths and Limitations
A significant limitation of this study was its small sample size; the study was not able to meet power for the primary outcome; it is unknown whether our study met power for nosocomial infections. The study also was not a powered review of other adverse events, such as thromboembolic complications, bleeding, and death. The study had an uneven number of patients, which made it more difficult to appropriately compare 2 patient populations; the study also did not include medians for patient characteristics and outcomes.
Due to this study’s time frame, the clinical pharmacy services at MEDVAMC were not as robust as they are now, which is the reason the decisions on which anticoagulant to use were primarily physician based. The use of TheraDoc to identify patients posed the risk of missing patients who may not have had the appropriate laboratory tests performed (ie, SCr). Patients on UFH had a reduced eGFR compared with that of enoxaparin, which may limit our extrapolation of enoxaparin’s use in end-stage renal disease. The reduced eGFR and higher number of dialysis patients in the UFH arm may have increased the occurrence of more labile INRs and bleeding outcomes. Patients on hemodialysis typically have more comorbidities and an increased risk of infection due to the frequent use of catheters and needles to access the bloodstream. In addition, the potential differences in catheter use and duration between groups were not identified. If these parameters were studied, the data collected may have helped better explain the reasoning for increased incidence of infection in the UFH arm.
Strengths of this study include a complex patient population with similar characteristics, distribution of ethnicities representative of the US population, patients at moderate-to-high thrombotic risk, the analysis of nosocomial infections, and the exclusion of patients with normal renal function or moderate CKD.
Conclusion
To our knowledge, this is the first study to compare periprocedural bridging outcomes and incidence of nosocomial infections in patients with AF and ACKD. This review provides new evidence that in this patient population, enoxaparin is a potential anticoagulant to reduce hospital LOS and hospital-acquired infections. Compared with UFH, bridging with enoxaparin reduced hospital LOS and anticoagulation time-to-discharge by 7 and 5 days, respectively, and decreased the incidence of nosocomial infections by 30%. Using the mean LOS per treating specialty for both arms, bridging 1 patient with AF with enoxaparin vs UFH can potentially lead to an estimated $40,000 (44%) reduction in total cost of hospitalization. Enoxaparin also had no numeric differences in mortality and adverse events (stroke/TIA, MI, VTE) vs that of UFH, but it is important to note that this study was not powered to find a significant difference in these outcomes. Due to the mean eGFR of patients on enoxaparin being 22.6 mL/min/1.73 m2 and only 1 in 5 having stage 5 CKD, at this time, we do not recommend enoxaparin for periprocedural use in stage 5 CKD or in patients on hemodialysis. Larger studies are needed, including randomized trials, in this patient population to further evaluate these outcomes and assess the use of enoxaparin in patients with ACKD.
1. Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2)(suppl):e326S-350S.
2. Douketis JD, Spyropoulos AC, Kaatz S, et al; BRIDGE Investigators. Perioperative bridging anticoagulation in patients with atrial fibrillation. N Engl J Med. 2015;373(9):823-833.
3. Hammerstingl C, Schmitz A, Fimmers R, Omran H. Bridging of chronic oral anticoagulation with enoxaparin in patients with atrial fibrillation: results from the prospective BRAVE registry. Cardiovasc Ther. 2009;27(4):230-238.
4. Dad T, Weiner DE. Stroke and chronic kidney disease: epidemiology, pathogenesis, and management across kidney disease stages. Semin Nephrol. 2015;35(4):311-322.
5. Wattanakit K, Cushman M. Chronic kidney disease and venous thromboembolism: epidemiology and mechanisms. Curr Opin Pulm Med. 2009;15(5):408-412.
6. Saltiel M. Dosing low molecular weight heparins in kidney disease. J Pharm Pract. 2010;23(3):205-209.
7. Spinler SA, Inverso SM, Cohen M, Goodman SG, Stringer KA, Antman EM; ESSENCE and TIMI 11B Investigators. Safety and efficacy of unfractionated heparin versus enoxaparin in patients who are obese and patients with severe renal impairment: analysis from the ESSENCE and TIMI 11B studies. Am Heart J. 2003;146(1):33-41.
8. Fox KA, Antman EM, Montalescot G, et al. The impact of renal dysfunction on outcomes in the ExTRACT-TIMI 25 trial. J Am Coll Cardiol. 2007;49(23):2249-2255.
9. Spyropoulos AC, Turpie AG, Dunn AS, et al; REGIMEN Investigators. Clinical outcomes with unfractionated heparin or low-molecular-weight heparin as bridging therapy in patients on long-term oral anticoagulants: the REGIMEN registry. J Thromb Haemost. 2006;4(6):1246-1252.
10. Amorosi SL, Tsilimingras K, Thompson D, Fanikos J, Weinstein MC, Goldhaber SZ. Cost analysis of “bridging therapy” with low-molecular-weight heparin versus unfractionated heparin during temporary interruption of chronic anticoagulation. Am J Cardiol. 2004;93(4):509-511.
11. Inker LA, Astor BC, Fox CH, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD. Am J Kidney Dis. 2014;63(5):713-735.
12. US Department of Veteran Affairs. Managerial Cost Accounting Financial User Support Reports: fiscal year 2018. https://www.herc.research.va.gov/include/page.asp?id=managerial-cost-accounting. [Source not verified.]
13. Doherty JU, Gluckman TJ, Hucker WJ, et al. 2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients With Nonvalvular Atrial Fibrillation: a report of the American College of Cardiology Clinical Expert Consensus Document Task Force. J Am Coll Cardiol. 2017;69(7):871-898.
14. Kearon C, Kahn SR, Agnelli G, et al. Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 suppl):454S-545S.
15. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994;47(11):1245-1251.
16. Lovenox [package insert]. Bridgewater, NJ: Sanofi-Aventis; December 2017.
17. Cruickshank MK, Levine MN, Hirsh J, Roberts R, Siguenza M. A standard heparin nomogram for the management of heparin therapy. Arch Intern Med. 1991;151(2):333-337.
18. Steinberg BA, Peterson ED, Kim S, et al; Outcomes Registry for Better Informed Treatment of Atrial Fibrillation Investigators and Patients. Use and outcomes associated with bridging during anticoagulation interruptions in patients with atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 2015;131(5):488-494.
19. Verheugt FW, Steinhubl SR, Hamon M, et al. Incidence, prognostic impact, and influence of antithrombotic therapy on access and nonaccess site bleeding in percutaneous coronary intervention. JACC Cardiovasc Interv. 2011;4(2):191-197.
20. Bijsterveld NR, Peters RJ, Murphy SA, Bernink PJ, Tijssen JG, Cohen M. Recurrent cardiac ischemic events early after discontinuation of short-term heparin treatment in acute coronary syndromes: results from the Thrombolysis in Myocardial Infarction (TIMI) 11B and Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events (ESSENCE) studies. J Am Coll Cardiol. 2003;42(12):2083-2089.
1. Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2)(suppl):e326S-350S.
2. Douketis JD, Spyropoulos AC, Kaatz S, et al; BRIDGE Investigators. Perioperative bridging anticoagulation in patients with atrial fibrillation. N Engl J Med. 2015;373(9):823-833.
3. Hammerstingl C, Schmitz A, Fimmers R, Omran H. Bridging of chronic oral anticoagulation with enoxaparin in patients with atrial fibrillation: results from the prospective BRAVE registry. Cardiovasc Ther. 2009;27(4):230-238.
4. Dad T, Weiner DE. Stroke and chronic kidney disease: epidemiology, pathogenesis, and management across kidney disease stages. Semin Nephrol. 2015;35(4):311-322.
5. Wattanakit K, Cushman M. Chronic kidney disease and venous thromboembolism: epidemiology and mechanisms. Curr Opin Pulm Med. 2009;15(5):408-412.
6. Saltiel M. Dosing low molecular weight heparins in kidney disease. J Pharm Pract. 2010;23(3):205-209.
7. Spinler SA, Inverso SM, Cohen M, Goodman SG, Stringer KA, Antman EM; ESSENCE and TIMI 11B Investigators. Safety and efficacy of unfractionated heparin versus enoxaparin in patients who are obese and patients with severe renal impairment: analysis from the ESSENCE and TIMI 11B studies. Am Heart J. 2003;146(1):33-41.
8. Fox KA, Antman EM, Montalescot G, et al. The impact of renal dysfunction on outcomes in the ExTRACT-TIMI 25 trial. J Am Coll Cardiol. 2007;49(23):2249-2255.
9. Spyropoulos AC, Turpie AG, Dunn AS, et al; REGIMEN Investigators. Clinical outcomes with unfractionated heparin or low-molecular-weight heparin as bridging therapy in patients on long-term oral anticoagulants: the REGIMEN registry. J Thromb Haemost. 2006;4(6):1246-1252.
10. Amorosi SL, Tsilimingras K, Thompson D, Fanikos J, Weinstein MC, Goldhaber SZ. Cost analysis of “bridging therapy” with low-molecular-weight heparin versus unfractionated heparin during temporary interruption of chronic anticoagulation. Am J Cardiol. 2004;93(4):509-511.
11. Inker LA, Astor BC, Fox CH, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD. Am J Kidney Dis. 2014;63(5):713-735.
12. US Department of Veteran Affairs. Managerial Cost Accounting Financial User Support Reports: fiscal year 2018. https://www.herc.research.va.gov/include/page.asp?id=managerial-cost-accounting. [Source not verified.]
13. Doherty JU, Gluckman TJ, Hucker WJ, et al. 2017 ACC Expert Consensus Decision Pathway for Periprocedural Management of Anticoagulation in Patients With Nonvalvular Atrial Fibrillation: a report of the American College of Cardiology Clinical Expert Consensus Document Task Force. J Am Coll Cardiol. 2017;69(7):871-898.
14. Kearon C, Kahn SR, Agnelli G, et al. Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 suppl):454S-545S.
15. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994;47(11):1245-1251.
16. Lovenox [package insert]. Bridgewater, NJ: Sanofi-Aventis; December 2017.
17. Cruickshank MK, Levine MN, Hirsh J, Roberts R, Siguenza M. A standard heparin nomogram for the management of heparin therapy. Arch Intern Med. 1991;151(2):333-337.
18. Steinberg BA, Peterson ED, Kim S, et al; Outcomes Registry for Better Informed Treatment of Atrial Fibrillation Investigators and Patients. Use and outcomes associated with bridging during anticoagulation interruptions in patients with atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 2015;131(5):488-494.
19. Verheugt FW, Steinhubl SR, Hamon M, et al. Incidence, prognostic impact, and influence of antithrombotic therapy on access and nonaccess site bleeding in percutaneous coronary intervention. JACC Cardiovasc Interv. 2011;4(2):191-197.
20. Bijsterveld NR, Peters RJ, Murphy SA, Bernink PJ, Tijssen JG, Cohen M. Recurrent cardiac ischemic events early after discontinuation of short-term heparin treatment in acute coronary syndromes: results from the Thrombolysis in Myocardial Infarction (TIMI) 11B and Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events (ESSENCE) studies. J Am Coll Cardiol. 2003;42(12):2083-2089.
Fluoroscopically Guided Lateral Approach Hip Injection
Hip injections are performed as diagnostic and therapeutic interventions across a variety of medical subspecialties, including but not limited to those practicing physical medicine and rehabilitation, pain medicine, sports medicine, orthopedic surgery, and radiology. Traditional image-guided intra-articular hip injection commonly uses an anterior-oblique approach from a starting point on the anterior groin traversing soft tissue anterior to the femoral neck to the target needle placement at the femoral head-neck junction.
In fluoroscopic procedures, a coaxial technique for needles placement is used for safe and precise insertion of needles. An X-ray beam is angled in line with the projected path of the needle from skin entry point to injection target. Coaxial, en face technique (also called EF, parallel, hub view, down the barrel, or barrel view) appears as a single radiopaque dot over the target injection site.1 This technique minimizes needle redirection for correction of the injection path and minimal disturbance of surrounding tissue on the approach to the intended target.
Noncoaxial technique, as used in the anterior-oblique approach, intentionally directs the needle away from a skin entry point, the needle barrel traversing the X-ray beam toward an injection target. Clinical challenges to injection with the anterior-oblique approach include using a noncoaxial technique. Additional challenges to the anterior-oblique (also referred to as anterior) approach are body habitus and pannus, proximity to neurovascular structures, and patient positioning. By understanding the risks and benefits of varied technical approaches to accomplish a clinical goal and outcome, trainees are better able to select the technique most appropriate for a varied patient population.
Common risks to patients for all intra-articular interventions include bleeding, infection, and pain. Risk of damage to nearby structures is often mentioned as part of a standard informed consent process as it relates to the femoral vein, artery, and nerve that are in close anatomical proximity to the target injection site. When prior studies have examined the risk of complications resulting from intra-articular hip injections, a common conclusion is that despite a relatively low-risk profile for skilled interventionalists, efforts to avoid needle placement in the medial 50% of the femoral head on antero-posterior imaging is recommended.2
The anterior technique is a commonly described approach, and the same can be used for both ultrasound-guided and fluoroscopically guided hip injections.3 Using ultrasound guidance, the anterior technique can be performed with in-plane direct visualization of the needle throughout the procedure. With fluoroscopic guidance, the anterior approach is performed out-of-plane, using the noncoaxial technique. This requires the interventionalist to use tactile and anatomic guidance to the target injection site. The anterior approach for hip injection is one of few interventions where coaxial technique is not used for the procedure, making the instruction for a learner less concrete and potentially more challenging related to the needle path not under direct visualization in plane with the X-ray beam.
Technical guidance and detailed instruction for the lateral approach is infrequently described in fluoroscopic interventional texts. Reference to a lateral approach hip injection was made as early as the 1970s, without detail provided on the technique, with respect to the advantage of visualization of the hip joint for needle placement when hardware is in place.4 A more recent article described a lateral approach technique involving the patient in a decubitus (lateral) supine position, which presents limitations in consistent fluoroscopic imaging and can be a challenging static position for the patient to maintain.5
The retrospective review of anterior-oblique and lateral approach procedures in this study aims to demonstrate that there is no significant difference in radiation exposure, rate of successful intra-articular injection, or complication rate. If proven as a noninferior technique, the lateral approach may be a valuable interventional skill to those performing hip injections. Potential benefits to the patient and provider include options for the provider to access the joint using either technique. Additionally, the approach can be added to the instructional plan for those practitioners providing technical instruction to trainees within their health care system.
Methods
The institutional review board at the VA Ann Arbor Healthcare System reviewed and granted approval for this study. One of 5 interventional pain physician staff members at the VA Ann Arbor Healthcare System performed fluoroscopically guided hip injections. Interventional pain fellows under the direct supervision of board-certified physicians performed the procedures for the study cases. Supervising physicians included both physiatrists and anesthesiologists. Images were reviewed and evaluated without corresponding patient biographic data.
For cases using the lateral approach, the patients were positioned supine on the fluoroscopy table. In anterior-posterior and lateral views, trajectory lines are drawn using a long metal marking rod held adjacent to the patient. With pulsed low-dose fluoroscopy, transverse lines are drawn to identify midpoint of the femoral head in lateral view (Figure 1A, x-axis) and the most direct line from skin to lateral femoral head neck junction joint target (Figure 1B, z-axis). Also confirmed in lateral view, the z-axis marked line drawn on the skin is used to confirm that this transverse plane crosses the overlapping femoral heads (Figure 1A, y-axis).
The cross-section of these transverse and coronal plane lines identifies the starting point for the most direct approach from skin to injection target at femoral head-neck junction. Using the coaxial technique in the lateral view, the needle is introduced and advanced using intermittent fluoroscopic images to the lateral joint target. Continuing in this view, the interventionalist can ensure that advancing the needle to the osseous endpoint will place the tip at the midpoint of the femoral head at the target on the lateral surface, avoiding inadvertent advance of the needle anterior or posterior the femoral head. Final needle placement confirmation is then completed in antero-posterior view (Figure 2A). Contrast enhancement is used to confirm intra-articular spread (Figure 2B).
Cases included in the study were performed over an 8-month period in 2017. Case images recorded in IntelliSpace PACS Radiology software (Andover, MA) were included by creating a list of all cases performed and documented using the major joint injection procedure code. The cases reviewed began with the most recent cases. Two research team members (1 radiologist and 1 interventional pain physician) reviewed the series of saved images for each patient and the associated procedure report. The research team members documented and recorded de-identified study data in Microsoft Excel (Redmond, WA).
Imaging reports, using the saved images and the associated procedure report, were classified for technical approach (anterior, lateral, or inconclusive), success of joint injection as evidenced by appropriate contrast enhancement within the joint space (successful, unsuccessful, or incomplete images), documented use of sedation (yes, no), patient positioning (supine, prone), radiation exposure dose, radiation exposure time, and additional comments, such as “notable pannus” or “hardware present” to annotate significant findings on imaging review.
Statistical Analysis
The distribution of 2 outcomes used to compare rates of complication, radiation dose, and exposure time was checked using the Shapiro-Wilk test. Power analysis determined that inclusion of 30 anterior and 30 lateral cases results in adequate power to detect a 1-point mean difference, assuming a standard deviation of 1.5 in each group. Both radiation dose and exposure time were found to be nonnormally distributed (W = 0.65, P < .001; W = 0.86, P < .001; respectively). Median and interquartile range (IQR) of dose and time in seconds for anterior and lateral approaches were computed. Median differences in radiation dose and exposure time between anterior and lateral approaches were assessed with the k-sample test of equality of medians. All analyses were conducted using Stata Version 14.1 (College Station, TX).
Results
Between June 2017 and January 2018, 88 cases were reviewed as performed, with 30 anterior and 30 lateral approach cases included in this retrospective comparison study. A total of 28 cases were excluded from the study for using an inconclusive approach, multiple or bilateral procedures, cases without recorded dose and time data, and inadequately saved images to provide meaningful data (Figure 3).
Rate of successful intervention with needle placement confirmed within the articular space on contrast enhancement was not significantly different in the study groups with 96.7% (29 of 30) anterior approach cases reported as successful, 100% (30 of 30) lateral approach cases reported as successful. Overhanging pannus in the viewing area was reported in 5 anterior approach cases and 4 lateral cases. Hardware was noted in 2 lateral approach cases, none in anterior approach cases. Sedation was used for 3 of the anterior approach cases and none of the lateral approach cases.
Patients undergoing the lateral approach received a higher median radiation dose than did those undergoing the anterior approach, but this was not statistically significant (P = .07) (Table). Those undergoing the lateral approach also had a longer median exposure time than did those undergoing the anterior approach, but this also was not statistically significant (P = .3). With no immediate complications reported in any of the studied interventions, there was no difference in complication rates between anterior and lateral approach cases.
Discussion
Pain medicine fellows who have previously completed residency in a variety of disciplines, often either anesthesiology or physical medicine and rehabilitation, perform fluoroscopically guided procedures and benefit from increased experience with coaxial technique as this improves needle depth and location awareness. Once mastered, this skill set can be applied to and useful for multiple interventional pain procedures. Similar technical instruction with an emphasis on coaxial technique for hip injections as performed in the anterior or anterolateral approach can be used in both fluoroscopic and ultrasound-guided procedures, including facet injection, transforaminal epidural steroid injection, and myriad other procedures performed to ameliorate pain. There are advantages to pursuing a similar approach with all image-guided procedures. Evaluated in this comparison study is an alternative technique that has potential for risk reduction benefit with reduced proximity to neurovascular structures, which ultimately leads to a safer procedure profile.
Using a lateral approach, the interventionalist determines a starting point, entering the skin at a greater distance from any overlying pannus and the elevated concentration of gram-negative and gram-positive bacteria contained within the inguinal skin.6 A previous study demonstrated improved success of intra-articular needle tip placement without image guidance in patients with body mass index (BMI) < 30.7 A prior study of anterior approach using anatomic landmarks as compared to lateral approach demonstrated the anterior approach pierced or contacted the femoral nerve in 27% of anterior cases and came within 5 mm of 60% of anterior cases.2 Use of image guidance, whether ultrasound, fluoroscopy, or computed tomography (CT) is preferred related to reduced risk of contact with adjacent neurovascular structures. Anatomic surface landmarks have been described as an alternative injection technique, without the use of fluoroscopy for confirmatory initial, intraprocedure, and final placement.8 Palpation of anatomic structures is required for this nonimage-guided technique, and although similar to the described technique in this study, the anatomically guided injection starting point is more lateral than the anterior approach but not in the most lateral position in the transverse plane that is used for this fluoroscopically guided lateral approach study.
Physiologic characteristics of subjects and technical aspects of fluoroscopy both can be factors in radiation dose and exposure times for hip injections. Patient BMI was not included in the data collection, but further study would seek to determine whether BMI is a significant risk for any increased radiation dose and exposure times using lateral approach injections. Use of lateral images for fluoroscopy requires penetration of X-ray beam through more tissue compared with that of anterior-posterior images. Further study of these techniques would benefit from comparing the pulse rate of fluoroscopic images and collimation (or focusing of the radiation beam over a smaller area of tissue) as factors in any observed increase in total radiation dose and exposure times.
Improving the safety profile of this procedure could have a positive impact on the patient population receiving fluoroscopic hip injections, both within the VA Ann Arbor Health System and elsewhere. While the study population was limited to the VA patient population seeking subspecialty nonsurgical joint care at a single tertiary care center, this technique is generalizable and can be used in most patients, as hip pain is a common condition necessitating nonoperative evaluation and treatment.
Radiation Exposures
As our analysis demonstrates, mean radiation dose exposure for each group was consistent with low (≤ 3 mSv) to moderate (> 3-20 mSv) annual effective doses in the general population.7 Both anterior and lateral median radiation dose of 1 mGy and 3 mGy, respectively, are within the standard exposure for radiographs of the pelvis (1.31 mGy).9 It is therefore reasonable to consider a lateral approach for hip injection, given the benefits of direct coaxial approach and avoiding needle entry through higher bacteria-concentrated skin.
The lateral approach did have increased radiation dose and exposure time, although it was not statistically significantly greater than the anterior approach. The difference between radiation dose and time to perform either technique was not clinically significant. One potential explanation for this is that the lateral technique has increased tissue to penetrate, which can be reduced with collimation and other fluoroscopic image adjustments. Additionally, as trainees progress in competency, fewer images should need to be obtained.7 We hypothesize that as familiarity and comfort with this technique increase, the number of images necessary for successful injection would decrease, leading to decreased radiation dose and exposure time. We would expect that in the hands of a board-certified interventionalist, radiation dose and exposure time would be significantly decreased as compared to our current dataset, and this is an area of planned further study. With our existing dataset, the majority of procedures were performed with trainees, with inadequate information documented for comparison of dose over time and procedural experience under individual physicians.
Notable strengths of this study are the direct comparison of the anterior approach when compared to the lateral approach with regard to radiation dose and exposure time, which we have not seen described in the literature. A detailed description of the technique may result in increased utilization by other providers. Data were collected from multiple providers, as board-certified pain physicians and board-eligible interventional pain fellows performed the procedures. This variability in providers increases the generalizability of the findings, with a variety of providers, disciplines, years of experiences, and type of training represented.
Limitations
Limitations include the retrospective nature of the study and the relatively small sample size. However, even with this limitation, it is notable that no statistically significant differences were observed in mean radiation dose or fluoroscopy exposure time, making the lateral approach, at minimum, a noninferior technique. Combined with the improved safety profile, this technique is a viable alternative to the traditional anterior-oblique approach. Further study should be performed, such as a prospective, randomized control trial investigating the 2 techniques and following pain scores and functional ability after the procedure.
Conclusion
Given the decreased procedural risk related to proximity of neurovascular structures and coaxial technique for needle advancement, lateral approach for hip injection should be considered by those in any discipline performing fluoroscopically guided procedures. Lateral technique may be particularly useful in technically challenging cases and when skin entry at the anterior groin is suboptimal, as a noninferior alternative to traditional anterior method.
1. Cianfoni A, Boulter DJ, Rumboldt Z, Sapton T, Bonaldi G. Guidelines to imaging landmarks for interventional spine procedures: fluoroscopy and CT anatomy. Neurographics. 2011;1(1):39-48.
2. Leopold SS, Battista V, Oliverio JA. Safety and efficacy of intraarticular hip injection using anatomic landmarks. Clin Orthop Relat Res. 2001;(391):192-197.
3. Dodré E, Lefebvre G, Cockenpot E, Chastanet P, Cotten A. Interventional MSK procedures: the hip. Br J Radiol. 2016;89(1057):20150408.
4. Hankey S, McCall IW, Park WM, O’Connor BT. Technical problems in arthrography of the painful hip arthroplasty. Clin Radiol. 1979;30(6):653-656.
5. Yasar E, Singh JR, Hill J, Akuthota V. Image-guided injections of the hip. J Nov Physiother Phys Rehabil. 2014;1(2):39-48.
6. Aly R, Maibach HI. Aerobic microbial flora of intertrigenous skin. Appl Environ Microbiol. 1977;33(1):97-100.
7. Fazel R, Krumholz HM, Wang W, et al. Exposure to low-dose ionizing radiation from medical imaging procedures. N Engl J Med. 2009;361(9):849-857.
8. Masoud MA, Said HG. Intra-articular hip injection using anatomic surface landmarks. Arthosc Tech. 2013;2(2):e147-e149.
9. Ofori K, Gordon SW, Akrobortu E, Ampene AA, Darko EO. Estimation of adult patient doses for selected x-ray diagnostic examinations. J Radiat Res Appl Sci. 2014;7(4):459-462.
Hip injections are performed as diagnostic and therapeutic interventions across a variety of medical subspecialties, including but not limited to those practicing physical medicine and rehabilitation, pain medicine, sports medicine, orthopedic surgery, and radiology. Traditional image-guided intra-articular hip injection commonly uses an anterior-oblique approach from a starting point on the anterior groin traversing soft tissue anterior to the femoral neck to the target needle placement at the femoral head-neck junction.
In fluoroscopic procedures, a coaxial technique for needles placement is used for safe and precise insertion of needles. An X-ray beam is angled in line with the projected path of the needle from skin entry point to injection target. Coaxial, en face technique (also called EF, parallel, hub view, down the barrel, or barrel view) appears as a single radiopaque dot over the target injection site.1 This technique minimizes needle redirection for correction of the injection path and minimal disturbance of surrounding tissue on the approach to the intended target.
Noncoaxial technique, as used in the anterior-oblique approach, intentionally directs the needle away from a skin entry point, the needle barrel traversing the X-ray beam toward an injection target. Clinical challenges to injection with the anterior-oblique approach include using a noncoaxial technique. Additional challenges to the anterior-oblique (also referred to as anterior) approach are body habitus and pannus, proximity to neurovascular structures, and patient positioning. By understanding the risks and benefits of varied technical approaches to accomplish a clinical goal and outcome, trainees are better able to select the technique most appropriate for a varied patient population.
Common risks to patients for all intra-articular interventions include bleeding, infection, and pain. Risk of damage to nearby structures is often mentioned as part of a standard informed consent process as it relates to the femoral vein, artery, and nerve that are in close anatomical proximity to the target injection site. When prior studies have examined the risk of complications resulting from intra-articular hip injections, a common conclusion is that despite a relatively low-risk profile for skilled interventionalists, efforts to avoid needle placement in the medial 50% of the femoral head on antero-posterior imaging is recommended.2
The anterior technique is a commonly described approach, and the same can be used for both ultrasound-guided and fluoroscopically guided hip injections.3 Using ultrasound guidance, the anterior technique can be performed with in-plane direct visualization of the needle throughout the procedure. With fluoroscopic guidance, the anterior approach is performed out-of-plane, using the noncoaxial technique. This requires the interventionalist to use tactile and anatomic guidance to the target injection site. The anterior approach for hip injection is one of few interventions where coaxial technique is not used for the procedure, making the instruction for a learner less concrete and potentially more challenging related to the needle path not under direct visualization in plane with the X-ray beam.
Technical guidance and detailed instruction for the lateral approach is infrequently described in fluoroscopic interventional texts. Reference to a lateral approach hip injection was made as early as the 1970s, without detail provided on the technique, with respect to the advantage of visualization of the hip joint for needle placement when hardware is in place.4 A more recent article described a lateral approach technique involving the patient in a decubitus (lateral) supine position, which presents limitations in consistent fluoroscopic imaging and can be a challenging static position for the patient to maintain.5
The retrospective review of anterior-oblique and lateral approach procedures in this study aims to demonstrate that there is no significant difference in radiation exposure, rate of successful intra-articular injection, or complication rate. If proven as a noninferior technique, the lateral approach may be a valuable interventional skill to those performing hip injections. Potential benefits to the patient and provider include options for the provider to access the joint using either technique. Additionally, the approach can be added to the instructional plan for those practitioners providing technical instruction to trainees within their health care system.
Methods
The institutional review board at the VA Ann Arbor Healthcare System reviewed and granted approval for this study. One of 5 interventional pain physician staff members at the VA Ann Arbor Healthcare System performed fluoroscopically guided hip injections. Interventional pain fellows under the direct supervision of board-certified physicians performed the procedures for the study cases. Supervising physicians included both physiatrists and anesthesiologists. Images were reviewed and evaluated without corresponding patient biographic data.
For cases using the lateral approach, the patients were positioned supine on the fluoroscopy table. In anterior-posterior and lateral views, trajectory lines are drawn using a long metal marking rod held adjacent to the patient. With pulsed low-dose fluoroscopy, transverse lines are drawn to identify midpoint of the femoral head in lateral view (Figure 1A, x-axis) and the most direct line from skin to lateral femoral head neck junction joint target (Figure 1B, z-axis). Also confirmed in lateral view, the z-axis marked line drawn on the skin is used to confirm that this transverse plane crosses the overlapping femoral heads (Figure 1A, y-axis).
The cross-section of these transverse and coronal plane lines identifies the starting point for the most direct approach from skin to injection target at femoral head-neck junction. Using the coaxial technique in the lateral view, the needle is introduced and advanced using intermittent fluoroscopic images to the lateral joint target. Continuing in this view, the interventionalist can ensure that advancing the needle to the osseous endpoint will place the tip at the midpoint of the femoral head at the target on the lateral surface, avoiding inadvertent advance of the needle anterior or posterior the femoral head. Final needle placement confirmation is then completed in antero-posterior view (Figure 2A). Contrast enhancement is used to confirm intra-articular spread (Figure 2B).
Cases included in the study were performed over an 8-month period in 2017. Case images recorded in IntelliSpace PACS Radiology software (Andover, MA) were included by creating a list of all cases performed and documented using the major joint injection procedure code. The cases reviewed began with the most recent cases. Two research team members (1 radiologist and 1 interventional pain physician) reviewed the series of saved images for each patient and the associated procedure report. The research team members documented and recorded de-identified study data in Microsoft Excel (Redmond, WA).
Imaging reports, using the saved images and the associated procedure report, were classified for technical approach (anterior, lateral, or inconclusive), success of joint injection as evidenced by appropriate contrast enhancement within the joint space (successful, unsuccessful, or incomplete images), documented use of sedation (yes, no), patient positioning (supine, prone), radiation exposure dose, radiation exposure time, and additional comments, such as “notable pannus” or “hardware present” to annotate significant findings on imaging review.
Statistical Analysis
The distribution of 2 outcomes used to compare rates of complication, radiation dose, and exposure time was checked using the Shapiro-Wilk test. Power analysis determined that inclusion of 30 anterior and 30 lateral cases results in adequate power to detect a 1-point mean difference, assuming a standard deviation of 1.5 in each group. Both radiation dose and exposure time were found to be nonnormally distributed (W = 0.65, P < .001; W = 0.86, P < .001; respectively). Median and interquartile range (IQR) of dose and time in seconds for anterior and lateral approaches were computed. Median differences in radiation dose and exposure time between anterior and lateral approaches were assessed with the k-sample test of equality of medians. All analyses were conducted using Stata Version 14.1 (College Station, TX).
Results
Between June 2017 and January 2018, 88 cases were reviewed as performed, with 30 anterior and 30 lateral approach cases included in this retrospective comparison study. A total of 28 cases were excluded from the study for using an inconclusive approach, multiple or bilateral procedures, cases without recorded dose and time data, and inadequately saved images to provide meaningful data (Figure 3).
Rate of successful intervention with needle placement confirmed within the articular space on contrast enhancement was not significantly different in the study groups with 96.7% (29 of 30) anterior approach cases reported as successful, 100% (30 of 30) lateral approach cases reported as successful. Overhanging pannus in the viewing area was reported in 5 anterior approach cases and 4 lateral cases. Hardware was noted in 2 lateral approach cases, none in anterior approach cases. Sedation was used for 3 of the anterior approach cases and none of the lateral approach cases.
Patients undergoing the lateral approach received a higher median radiation dose than did those undergoing the anterior approach, but this was not statistically significant (P = .07) (Table). Those undergoing the lateral approach also had a longer median exposure time than did those undergoing the anterior approach, but this also was not statistically significant (P = .3). With no immediate complications reported in any of the studied interventions, there was no difference in complication rates between anterior and lateral approach cases.
Discussion
Pain medicine fellows who have previously completed residency in a variety of disciplines, often either anesthesiology or physical medicine and rehabilitation, perform fluoroscopically guided procedures and benefit from increased experience with coaxial technique as this improves needle depth and location awareness. Once mastered, this skill set can be applied to and useful for multiple interventional pain procedures. Similar technical instruction with an emphasis on coaxial technique for hip injections as performed in the anterior or anterolateral approach can be used in both fluoroscopic and ultrasound-guided procedures, including facet injection, transforaminal epidural steroid injection, and myriad other procedures performed to ameliorate pain. There are advantages to pursuing a similar approach with all image-guided procedures. Evaluated in this comparison study is an alternative technique that has potential for risk reduction benefit with reduced proximity to neurovascular structures, which ultimately leads to a safer procedure profile.
Using a lateral approach, the interventionalist determines a starting point, entering the skin at a greater distance from any overlying pannus and the elevated concentration of gram-negative and gram-positive bacteria contained within the inguinal skin.6 A previous study demonstrated improved success of intra-articular needle tip placement without image guidance in patients with body mass index (BMI) < 30.7 A prior study of anterior approach using anatomic landmarks as compared to lateral approach demonstrated the anterior approach pierced or contacted the femoral nerve in 27% of anterior cases and came within 5 mm of 60% of anterior cases.2 Use of image guidance, whether ultrasound, fluoroscopy, or computed tomography (CT) is preferred related to reduced risk of contact with adjacent neurovascular structures. Anatomic surface landmarks have been described as an alternative injection technique, without the use of fluoroscopy for confirmatory initial, intraprocedure, and final placement.8 Palpation of anatomic structures is required for this nonimage-guided technique, and although similar to the described technique in this study, the anatomically guided injection starting point is more lateral than the anterior approach but not in the most lateral position in the transverse plane that is used for this fluoroscopically guided lateral approach study.
Physiologic characteristics of subjects and technical aspects of fluoroscopy both can be factors in radiation dose and exposure times for hip injections. Patient BMI was not included in the data collection, but further study would seek to determine whether BMI is a significant risk for any increased radiation dose and exposure times using lateral approach injections. Use of lateral images for fluoroscopy requires penetration of X-ray beam through more tissue compared with that of anterior-posterior images. Further study of these techniques would benefit from comparing the pulse rate of fluoroscopic images and collimation (or focusing of the radiation beam over a smaller area of tissue) as factors in any observed increase in total radiation dose and exposure times.
Improving the safety profile of this procedure could have a positive impact on the patient population receiving fluoroscopic hip injections, both within the VA Ann Arbor Health System and elsewhere. While the study population was limited to the VA patient population seeking subspecialty nonsurgical joint care at a single tertiary care center, this technique is generalizable and can be used in most patients, as hip pain is a common condition necessitating nonoperative evaluation and treatment.
Radiation Exposures
As our analysis demonstrates, mean radiation dose exposure for each group was consistent with low (≤ 3 mSv) to moderate (> 3-20 mSv) annual effective doses in the general population.7 Both anterior and lateral median radiation dose of 1 mGy and 3 mGy, respectively, are within the standard exposure for radiographs of the pelvis (1.31 mGy).9 It is therefore reasonable to consider a lateral approach for hip injection, given the benefits of direct coaxial approach and avoiding needle entry through higher bacteria-concentrated skin.
The lateral approach did have increased radiation dose and exposure time, although it was not statistically significantly greater than the anterior approach. The difference between radiation dose and time to perform either technique was not clinically significant. One potential explanation for this is that the lateral technique has increased tissue to penetrate, which can be reduced with collimation and other fluoroscopic image adjustments. Additionally, as trainees progress in competency, fewer images should need to be obtained.7 We hypothesize that as familiarity and comfort with this technique increase, the number of images necessary for successful injection would decrease, leading to decreased radiation dose and exposure time. We would expect that in the hands of a board-certified interventionalist, radiation dose and exposure time would be significantly decreased as compared to our current dataset, and this is an area of planned further study. With our existing dataset, the majority of procedures were performed with trainees, with inadequate information documented for comparison of dose over time and procedural experience under individual physicians.
Notable strengths of this study are the direct comparison of the anterior approach when compared to the lateral approach with regard to radiation dose and exposure time, which we have not seen described in the literature. A detailed description of the technique may result in increased utilization by other providers. Data were collected from multiple providers, as board-certified pain physicians and board-eligible interventional pain fellows performed the procedures. This variability in providers increases the generalizability of the findings, with a variety of providers, disciplines, years of experiences, and type of training represented.
Limitations
Limitations include the retrospective nature of the study and the relatively small sample size. However, even with this limitation, it is notable that no statistically significant differences were observed in mean radiation dose or fluoroscopy exposure time, making the lateral approach, at minimum, a noninferior technique. Combined with the improved safety profile, this technique is a viable alternative to the traditional anterior-oblique approach. Further study should be performed, such as a prospective, randomized control trial investigating the 2 techniques and following pain scores and functional ability after the procedure.
Conclusion
Given the decreased procedural risk related to proximity of neurovascular structures and coaxial technique for needle advancement, lateral approach for hip injection should be considered by those in any discipline performing fluoroscopically guided procedures. Lateral technique may be particularly useful in technically challenging cases and when skin entry at the anterior groin is suboptimal, as a noninferior alternative to traditional anterior method.
Hip injections are performed as diagnostic and therapeutic interventions across a variety of medical subspecialties, including but not limited to those practicing physical medicine and rehabilitation, pain medicine, sports medicine, orthopedic surgery, and radiology. Traditional image-guided intra-articular hip injection commonly uses an anterior-oblique approach from a starting point on the anterior groin traversing soft tissue anterior to the femoral neck to the target needle placement at the femoral head-neck junction.
In fluoroscopic procedures, a coaxial technique for needles placement is used for safe and precise insertion of needles. An X-ray beam is angled in line with the projected path of the needle from skin entry point to injection target. Coaxial, en face technique (also called EF, parallel, hub view, down the barrel, or barrel view) appears as a single radiopaque dot over the target injection site.1 This technique minimizes needle redirection for correction of the injection path and minimal disturbance of surrounding tissue on the approach to the intended target.
Noncoaxial technique, as used in the anterior-oblique approach, intentionally directs the needle away from a skin entry point, the needle barrel traversing the X-ray beam toward an injection target. Clinical challenges to injection with the anterior-oblique approach include using a noncoaxial technique. Additional challenges to the anterior-oblique (also referred to as anterior) approach are body habitus and pannus, proximity to neurovascular structures, and patient positioning. By understanding the risks and benefits of varied technical approaches to accomplish a clinical goal and outcome, trainees are better able to select the technique most appropriate for a varied patient population.
Common risks to patients for all intra-articular interventions include bleeding, infection, and pain. Risk of damage to nearby structures is often mentioned as part of a standard informed consent process as it relates to the femoral vein, artery, and nerve that are in close anatomical proximity to the target injection site. When prior studies have examined the risk of complications resulting from intra-articular hip injections, a common conclusion is that despite a relatively low-risk profile for skilled interventionalists, efforts to avoid needle placement in the medial 50% of the femoral head on antero-posterior imaging is recommended.2
The anterior technique is a commonly described approach, and the same can be used for both ultrasound-guided and fluoroscopically guided hip injections.3 Using ultrasound guidance, the anterior technique can be performed with in-plane direct visualization of the needle throughout the procedure. With fluoroscopic guidance, the anterior approach is performed out-of-plane, using the noncoaxial technique. This requires the interventionalist to use tactile and anatomic guidance to the target injection site. The anterior approach for hip injection is one of few interventions where coaxial technique is not used for the procedure, making the instruction for a learner less concrete and potentially more challenging related to the needle path not under direct visualization in plane with the X-ray beam.
Technical guidance and detailed instruction for the lateral approach is infrequently described in fluoroscopic interventional texts. Reference to a lateral approach hip injection was made as early as the 1970s, without detail provided on the technique, with respect to the advantage of visualization of the hip joint for needle placement when hardware is in place.4 A more recent article described a lateral approach technique involving the patient in a decubitus (lateral) supine position, which presents limitations in consistent fluoroscopic imaging and can be a challenging static position for the patient to maintain.5
The retrospective review of anterior-oblique and lateral approach procedures in this study aims to demonstrate that there is no significant difference in radiation exposure, rate of successful intra-articular injection, or complication rate. If proven as a noninferior technique, the lateral approach may be a valuable interventional skill to those performing hip injections. Potential benefits to the patient and provider include options for the provider to access the joint using either technique. Additionally, the approach can be added to the instructional plan for those practitioners providing technical instruction to trainees within their health care system.
Methods
The institutional review board at the VA Ann Arbor Healthcare System reviewed and granted approval for this study. One of 5 interventional pain physician staff members at the VA Ann Arbor Healthcare System performed fluoroscopically guided hip injections. Interventional pain fellows under the direct supervision of board-certified physicians performed the procedures for the study cases. Supervising physicians included both physiatrists and anesthesiologists. Images were reviewed and evaluated without corresponding patient biographic data.
For cases using the lateral approach, the patients were positioned supine on the fluoroscopy table. In anterior-posterior and lateral views, trajectory lines are drawn using a long metal marking rod held adjacent to the patient. With pulsed low-dose fluoroscopy, transverse lines are drawn to identify midpoint of the femoral head in lateral view (Figure 1A, x-axis) and the most direct line from skin to lateral femoral head neck junction joint target (Figure 1B, z-axis). Also confirmed in lateral view, the z-axis marked line drawn on the skin is used to confirm that this transverse plane crosses the overlapping femoral heads (Figure 1A, y-axis).
The cross-section of these transverse and coronal plane lines identifies the starting point for the most direct approach from skin to injection target at femoral head-neck junction. Using the coaxial technique in the lateral view, the needle is introduced and advanced using intermittent fluoroscopic images to the lateral joint target. Continuing in this view, the interventionalist can ensure that advancing the needle to the osseous endpoint will place the tip at the midpoint of the femoral head at the target on the lateral surface, avoiding inadvertent advance of the needle anterior or posterior the femoral head. Final needle placement confirmation is then completed in antero-posterior view (Figure 2A). Contrast enhancement is used to confirm intra-articular spread (Figure 2B).
Cases included in the study were performed over an 8-month period in 2017. Case images recorded in IntelliSpace PACS Radiology software (Andover, MA) were included by creating a list of all cases performed and documented using the major joint injection procedure code. The cases reviewed began with the most recent cases. Two research team members (1 radiologist and 1 interventional pain physician) reviewed the series of saved images for each patient and the associated procedure report. The research team members documented and recorded de-identified study data in Microsoft Excel (Redmond, WA).
Imaging reports, using the saved images and the associated procedure report, were classified for technical approach (anterior, lateral, or inconclusive), success of joint injection as evidenced by appropriate contrast enhancement within the joint space (successful, unsuccessful, or incomplete images), documented use of sedation (yes, no), patient positioning (supine, prone), radiation exposure dose, radiation exposure time, and additional comments, such as “notable pannus” or “hardware present” to annotate significant findings on imaging review.
Statistical Analysis
The distribution of 2 outcomes used to compare rates of complication, radiation dose, and exposure time was checked using the Shapiro-Wilk test. Power analysis determined that inclusion of 30 anterior and 30 lateral cases results in adequate power to detect a 1-point mean difference, assuming a standard deviation of 1.5 in each group. Both radiation dose and exposure time were found to be nonnormally distributed (W = 0.65, P < .001; W = 0.86, P < .001; respectively). Median and interquartile range (IQR) of dose and time in seconds for anterior and lateral approaches were computed. Median differences in radiation dose and exposure time between anterior and lateral approaches were assessed with the k-sample test of equality of medians. All analyses were conducted using Stata Version 14.1 (College Station, TX).
Results
Between June 2017 and January 2018, 88 cases were reviewed as performed, with 30 anterior and 30 lateral approach cases included in this retrospective comparison study. A total of 28 cases were excluded from the study for using an inconclusive approach, multiple or bilateral procedures, cases without recorded dose and time data, and inadequately saved images to provide meaningful data (Figure 3).
Rate of successful intervention with needle placement confirmed within the articular space on contrast enhancement was not significantly different in the study groups with 96.7% (29 of 30) anterior approach cases reported as successful, 100% (30 of 30) lateral approach cases reported as successful. Overhanging pannus in the viewing area was reported in 5 anterior approach cases and 4 lateral cases. Hardware was noted in 2 lateral approach cases, none in anterior approach cases. Sedation was used for 3 of the anterior approach cases and none of the lateral approach cases.
Patients undergoing the lateral approach received a higher median radiation dose than did those undergoing the anterior approach, but this was not statistically significant (P = .07) (Table). Those undergoing the lateral approach also had a longer median exposure time than did those undergoing the anterior approach, but this also was not statistically significant (P = .3). With no immediate complications reported in any of the studied interventions, there was no difference in complication rates between anterior and lateral approach cases.
Discussion
Pain medicine fellows who have previously completed residency in a variety of disciplines, often either anesthesiology or physical medicine and rehabilitation, perform fluoroscopically guided procedures and benefit from increased experience with coaxial technique as this improves needle depth and location awareness. Once mastered, this skill set can be applied to and useful for multiple interventional pain procedures. Similar technical instruction with an emphasis on coaxial technique for hip injections as performed in the anterior or anterolateral approach can be used in both fluoroscopic and ultrasound-guided procedures, including facet injection, transforaminal epidural steroid injection, and myriad other procedures performed to ameliorate pain. There are advantages to pursuing a similar approach with all image-guided procedures. Evaluated in this comparison study is an alternative technique that has potential for risk reduction benefit with reduced proximity to neurovascular structures, which ultimately leads to a safer procedure profile.
Using a lateral approach, the interventionalist determines a starting point, entering the skin at a greater distance from any overlying pannus and the elevated concentration of gram-negative and gram-positive bacteria contained within the inguinal skin.6 A previous study demonstrated improved success of intra-articular needle tip placement without image guidance in patients with body mass index (BMI) < 30.7 A prior study of anterior approach using anatomic landmarks as compared to lateral approach demonstrated the anterior approach pierced or contacted the femoral nerve in 27% of anterior cases and came within 5 mm of 60% of anterior cases.2 Use of image guidance, whether ultrasound, fluoroscopy, or computed tomography (CT) is preferred related to reduced risk of contact with adjacent neurovascular structures. Anatomic surface landmarks have been described as an alternative injection technique, without the use of fluoroscopy for confirmatory initial, intraprocedure, and final placement.8 Palpation of anatomic structures is required for this nonimage-guided technique, and although similar to the described technique in this study, the anatomically guided injection starting point is more lateral than the anterior approach but not in the most lateral position in the transverse plane that is used for this fluoroscopically guided lateral approach study.
Physiologic characteristics of subjects and technical aspects of fluoroscopy both can be factors in radiation dose and exposure times for hip injections. Patient BMI was not included in the data collection, but further study would seek to determine whether BMI is a significant risk for any increased radiation dose and exposure times using lateral approach injections. Use of lateral images for fluoroscopy requires penetration of X-ray beam through more tissue compared with that of anterior-posterior images. Further study of these techniques would benefit from comparing the pulse rate of fluoroscopic images and collimation (or focusing of the radiation beam over a smaller area of tissue) as factors in any observed increase in total radiation dose and exposure times.
Improving the safety profile of this procedure could have a positive impact on the patient population receiving fluoroscopic hip injections, both within the VA Ann Arbor Health System and elsewhere. While the study population was limited to the VA patient population seeking subspecialty nonsurgical joint care at a single tertiary care center, this technique is generalizable and can be used in most patients, as hip pain is a common condition necessitating nonoperative evaluation and treatment.
Radiation Exposures
As our analysis demonstrates, mean radiation dose exposure for each group was consistent with low (≤ 3 mSv) to moderate (> 3-20 mSv) annual effective doses in the general population.7 Both anterior and lateral median radiation dose of 1 mGy and 3 mGy, respectively, are within the standard exposure for radiographs of the pelvis (1.31 mGy).9 It is therefore reasonable to consider a lateral approach for hip injection, given the benefits of direct coaxial approach and avoiding needle entry through higher bacteria-concentrated skin.
The lateral approach did have increased radiation dose and exposure time, although it was not statistically significantly greater than the anterior approach. The difference between radiation dose and time to perform either technique was not clinically significant. One potential explanation for this is that the lateral technique has increased tissue to penetrate, which can be reduced with collimation and other fluoroscopic image adjustments. Additionally, as trainees progress in competency, fewer images should need to be obtained.7 We hypothesize that as familiarity and comfort with this technique increase, the number of images necessary for successful injection would decrease, leading to decreased radiation dose and exposure time. We would expect that in the hands of a board-certified interventionalist, radiation dose and exposure time would be significantly decreased as compared to our current dataset, and this is an area of planned further study. With our existing dataset, the majority of procedures were performed with trainees, with inadequate information documented for comparison of dose over time and procedural experience under individual physicians.
Notable strengths of this study are the direct comparison of the anterior approach when compared to the lateral approach with regard to radiation dose and exposure time, which we have not seen described in the literature. A detailed description of the technique may result in increased utilization by other providers. Data were collected from multiple providers, as board-certified pain physicians and board-eligible interventional pain fellows performed the procedures. This variability in providers increases the generalizability of the findings, with a variety of providers, disciplines, years of experiences, and type of training represented.
Limitations
Limitations include the retrospective nature of the study and the relatively small sample size. However, even with this limitation, it is notable that no statistically significant differences were observed in mean radiation dose or fluoroscopy exposure time, making the lateral approach, at minimum, a noninferior technique. Combined with the improved safety profile, this technique is a viable alternative to the traditional anterior-oblique approach. Further study should be performed, such as a prospective, randomized control trial investigating the 2 techniques and following pain scores and functional ability after the procedure.
Conclusion
Given the decreased procedural risk related to proximity of neurovascular structures and coaxial technique for needle advancement, lateral approach for hip injection should be considered by those in any discipline performing fluoroscopically guided procedures. Lateral technique may be particularly useful in technically challenging cases and when skin entry at the anterior groin is suboptimal, as a noninferior alternative to traditional anterior method.
1. Cianfoni A, Boulter DJ, Rumboldt Z, Sapton T, Bonaldi G. Guidelines to imaging landmarks for interventional spine procedures: fluoroscopy and CT anatomy. Neurographics. 2011;1(1):39-48.
2. Leopold SS, Battista V, Oliverio JA. Safety and efficacy of intraarticular hip injection using anatomic landmarks. Clin Orthop Relat Res. 2001;(391):192-197.
3. Dodré E, Lefebvre G, Cockenpot E, Chastanet P, Cotten A. Interventional MSK procedures: the hip. Br J Radiol. 2016;89(1057):20150408.
4. Hankey S, McCall IW, Park WM, O’Connor BT. Technical problems in arthrography of the painful hip arthroplasty. Clin Radiol. 1979;30(6):653-656.
5. Yasar E, Singh JR, Hill J, Akuthota V. Image-guided injections of the hip. J Nov Physiother Phys Rehabil. 2014;1(2):39-48.
6. Aly R, Maibach HI. Aerobic microbial flora of intertrigenous skin. Appl Environ Microbiol. 1977;33(1):97-100.
7. Fazel R, Krumholz HM, Wang W, et al. Exposure to low-dose ionizing radiation from medical imaging procedures. N Engl J Med. 2009;361(9):849-857.
8. Masoud MA, Said HG. Intra-articular hip injection using anatomic surface landmarks. Arthosc Tech. 2013;2(2):e147-e149.
9. Ofori K, Gordon SW, Akrobortu E, Ampene AA, Darko EO. Estimation of adult patient doses for selected x-ray diagnostic examinations. J Radiat Res Appl Sci. 2014;7(4):459-462.
1. Cianfoni A, Boulter DJ, Rumboldt Z, Sapton T, Bonaldi G. Guidelines to imaging landmarks for interventional spine procedures: fluoroscopy and CT anatomy. Neurographics. 2011;1(1):39-48.
2. Leopold SS, Battista V, Oliverio JA. Safety and efficacy of intraarticular hip injection using anatomic landmarks. Clin Orthop Relat Res. 2001;(391):192-197.
3. Dodré E, Lefebvre G, Cockenpot E, Chastanet P, Cotten A. Interventional MSK procedures: the hip. Br J Radiol. 2016;89(1057):20150408.
4. Hankey S, McCall IW, Park WM, O’Connor BT. Technical problems in arthrography of the painful hip arthroplasty. Clin Radiol. 1979;30(6):653-656.
5. Yasar E, Singh JR, Hill J, Akuthota V. Image-guided injections of the hip. J Nov Physiother Phys Rehabil. 2014;1(2):39-48.
6. Aly R, Maibach HI. Aerobic microbial flora of intertrigenous skin. Appl Environ Microbiol. 1977;33(1):97-100.
7. Fazel R, Krumholz HM, Wang W, et al. Exposure to low-dose ionizing radiation from medical imaging procedures. N Engl J Med. 2009;361(9):849-857.
8. Masoud MA, Said HG. Intra-articular hip injection using anatomic surface landmarks. Arthosc Tech. 2013;2(2):e147-e149.
9. Ofori K, Gordon SW, Akrobortu E, Ampene AA, Darko EO. Estimation of adult patient doses for selected x-ray diagnostic examinations. J Radiat Res Appl Sci. 2014;7(4):459-462.
The Shot That Won the Revolutionary War and Is Still Reverberating
The disputes about those who decline to vaccinate their children for communicable infectious diseases, especially measles, have been in the headlines of late. Those refusals are often done in the name of “medical freedom.”1 Yet this is a much older debate for the military. It seems fitting in this month in which we celebrate the 243rd anniversary of the Declaration of Independence to reflect on the earliest history of the interaction between vaccinations and war in the US and what it tells us about the fight for religious and political freedom and individual liberty.
Go back in time with me to 1776, long before the Fourth of July was a day for barbecues and fireworks. We are in Boston, Philadelphia, and other important cities in colonial America. This time, concern was not about measles but the even more dreaded smallpox. In the first years of the Revolutionary War, General George Washington took command of a newly formed and named Continental Army. A catastrophic 90% of casualties in the Continental Army were from infectious diseases, with the lion’s share of these from smallpox, which at that time had a mortality rate of about 30%.2,3
Early efforts to introduce inoculation into the colonies had failed for many of the same reasons parents across the US today refuse immunization: fear and anxiety. When the renowned New England Puritan minister and scientist Cotton Mather attempted in 1721 to introduce variolation, his house was firebombed and his fellow clergy and physicians alleged that his efforts at inoculation were challenging God’s will to send a plague.3 Variolation was the now antiquated and then laborious process in which a previously unexposed individual was inoculated with material from the vesicle of someone infected with the disease.4,5 Variolation was practiced in parts of Africa and Asia and among wealthy Europeans but remained controversial in many colonies where few Americans had been exposed to smallpox or could afford the procedure.3
It is important to note that the use of variolation was practiced before Edward Jenner famously demonstrated that cowpox vaccine could provide immunity to smallpox in 1798. The majority of those inoculated would develop a mild case of smallpox that required a 5-week period of illness and recovery that provided lifelong immunity. However, during those 5 weeks, they remained a vector of disease for the uninoculated. Southern and New England colonies passed laws that prohibited variolation. Those anti-inoculation attitudes were the basis for the order given to the surgeons general of the Continental Army in 1776 that all inoculations of the troops were forbidden, despite the fact that perhaps only 25% of soldiers possessed any natural immunity.2,3
There was yet another reason that many colonial Americans opposed government-sponsored preventative care, and it was the same reason that they were fighting a war of independence: distrust and resentment of authority. The modern antivaccine movement voices similar fears and suspicions regarding public health campaigns and especially legislative efforts to mandate vaccinations or remove extant exemptions.
In 1775 in Boston, a smallpox outbreak occurred at the same time the Americans laid siege to the British troops occupying the city. Greater natural immunity to the scourge of smallpox either through exposure or variolation provided the British with a stronger defense than the mere city fortifications. There are even some suspicions that the British used the virus as a proto-biologic weapon.
General Washington had initially been against inoculation until he realized that without it the British might win the war. This possibility presented him with a momentous decision: inoculate despite widespread anxiety that variolation would spread the disease or risk the virus ravaging the fighting force. Perhaps the most compelling reason to variolate was that new recruits refused to sign up, fearing not that they would die in battle but of smallpox. In 1777, Washington mandated variolation of the nonimmune troops and new recruits, making it the first large-scale military preventative care measure in history.
Recapitulating an ethical dilemma that still rages in the military nearly 3 centuries later, for British soldiers, inoculation was voluntary not compulsory as for the Americans. There was so much opposition to Washington’s order that communications with surgeons were secret, and commanding officers had to oversee the inoculations.2,3
Washington’s policy not only contributed mightily to the American victory in the war, but also set the precedent for compulsory vaccination in the US military for the next 3 centuries. Currently, regulations require that service members be vaccinated for multiple infectious diseases. Of interest, this mandatory vaccination program has led to no reported cases of measles among military families to date, in part because of federal regulations requiring families of those service members to be vaccinated.6
Ironically, once General Washington made the decision for mass inoculation, he encountered little actual resistance among the troops. However, throughout military history some service members have objected to compulsory vaccination on medical, religious, and personal grounds. In United States v Chadwell, a military court ruled against 2 Marine Corps members who refused vaccination for smallpox, typhoid, paratyphoid, and influenza, citing religious grounds. The court opined that the military orders that ensure the health and safety of the armed forces and thereby that of the public override personal religious beliefs.7
The paradox of liberty—the liberty first won in the Revolutionary War—is that in a pluralistic representative democracy like ours to secure the freedom for all, some, such as the military, must relinquish the very choice to refuse. Their sacrifices grant liberty to others. On June 6, we commemorated the seventy-fifth anniversary of D-Day, remembering how great the cost of that eternal vigilance, which the patriot Thomas Paine said was the price of liberty. On Memorial Day, we remember all those men and women who died in the service of their country. And while they gave up the most precious gift, we must never forget that every person in uniform also surrenders many other significant personal freedoms so that their fellow civilians may exercise them.
The question General Washington faced is one that public health authorities and our legislators again confront. When should the freedom to refuse, which was won with the blood of many valiant heroes and has been defended since 1776, be curtailed for the greater good? We are the one nation in history that has made the defense of self-determination its highest value and in so doing, its greatest challenge.
1. Sun LH. Senate panel warns of dangers of ant-vaccine movement. https://www.washingtonpost.com/health/2019/03/05/combat-anti-vaxxers-us-needs-national-campaign-top-washington-state-official-says/?utm_term=.9a4201be0ed1. Published March 5, 2019. Accessed June 9, 2019.
2. Filsinger AL, Dwek R. George Washington and the first mass military inoculation. http://www.loc.gov/rr/scitech/GW&smallpoxinoculation.html. Published February 12, 2009. Accessed June 10, 2019.
3. Fenn EA. Pox Americana. New York: Hill and Wang; 2001.
4. Steadman’s Medical Dictionary. 28th edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2006.
5. Artenstein AW, Opal JM, Opal SM, Tramont EC, Georges P, Russell PK. History of U.S. military contributions to the study of vaccines and infectious diseases. Mil Med. 2005;170(suppl 4):3-11.
6. Jowers K. So far, no measles cases at military medical facilities—but officials are watching. https://www.militarytimes.com/pay-benefits/2019/04/19/so-far-no-measles-cases-at-military-medical-facilities-but-officials-are-watching/. Published April 19, 2019. Accessed June 9, 2019.
7. Cole JP, Swendiman KS. Mandatory vaccinations: precedent and current laws. https://fas.org/sgp/crs/misc/RS21414.pdf. Published May 21, 2014. Accessed June 10, 2019.
The disputes about those who decline to vaccinate their children for communicable infectious diseases, especially measles, have been in the headlines of late. Those refusals are often done in the name of “medical freedom.”1 Yet this is a much older debate for the military. It seems fitting in this month in which we celebrate the 243rd anniversary of the Declaration of Independence to reflect on the earliest history of the interaction between vaccinations and war in the US and what it tells us about the fight for religious and political freedom and individual liberty.
Go back in time with me to 1776, long before the Fourth of July was a day for barbecues and fireworks. We are in Boston, Philadelphia, and other important cities in colonial America. This time, concern was not about measles but the even more dreaded smallpox. In the first years of the Revolutionary War, General George Washington took command of a newly formed and named Continental Army. A catastrophic 90% of casualties in the Continental Army were from infectious diseases, with the lion’s share of these from smallpox, which at that time had a mortality rate of about 30%.2,3
Early efforts to introduce inoculation into the colonies had failed for many of the same reasons parents across the US today refuse immunization: fear and anxiety. When the renowned New England Puritan minister and scientist Cotton Mather attempted in 1721 to introduce variolation, his house was firebombed and his fellow clergy and physicians alleged that his efforts at inoculation were challenging God’s will to send a plague.3 Variolation was the now antiquated and then laborious process in which a previously unexposed individual was inoculated with material from the vesicle of someone infected with the disease.4,5 Variolation was practiced in parts of Africa and Asia and among wealthy Europeans but remained controversial in many colonies where few Americans had been exposed to smallpox or could afford the procedure.3
It is important to note that the use of variolation was practiced before Edward Jenner famously demonstrated that cowpox vaccine could provide immunity to smallpox in 1798. The majority of those inoculated would develop a mild case of smallpox that required a 5-week period of illness and recovery that provided lifelong immunity. However, during those 5 weeks, they remained a vector of disease for the uninoculated. Southern and New England colonies passed laws that prohibited variolation. Those anti-inoculation attitudes were the basis for the order given to the surgeons general of the Continental Army in 1776 that all inoculations of the troops were forbidden, despite the fact that perhaps only 25% of soldiers possessed any natural immunity.2,3
There was yet another reason that many colonial Americans opposed government-sponsored preventative care, and it was the same reason that they were fighting a war of independence: distrust and resentment of authority. The modern antivaccine movement voices similar fears and suspicions regarding public health campaigns and especially legislative efforts to mandate vaccinations or remove extant exemptions.
In 1775 in Boston, a smallpox outbreak occurred at the same time the Americans laid siege to the British troops occupying the city. Greater natural immunity to the scourge of smallpox either through exposure or variolation provided the British with a stronger defense than the mere city fortifications. There are even some suspicions that the British used the virus as a proto-biologic weapon.
General Washington had initially been against inoculation until he realized that without it the British might win the war. This possibility presented him with a momentous decision: inoculate despite widespread anxiety that variolation would spread the disease or risk the virus ravaging the fighting force. Perhaps the most compelling reason to variolate was that new recruits refused to sign up, fearing not that they would die in battle but of smallpox. In 1777, Washington mandated variolation of the nonimmune troops and new recruits, making it the first large-scale military preventative care measure in history.
Recapitulating an ethical dilemma that still rages in the military nearly 3 centuries later, for British soldiers, inoculation was voluntary not compulsory as for the Americans. There was so much opposition to Washington’s order that communications with surgeons were secret, and commanding officers had to oversee the inoculations.2,3
Washington’s policy not only contributed mightily to the American victory in the war, but also set the precedent for compulsory vaccination in the US military for the next 3 centuries. Currently, regulations require that service members be vaccinated for multiple infectious diseases. Of interest, this mandatory vaccination program has led to no reported cases of measles among military families to date, in part because of federal regulations requiring families of those service members to be vaccinated.6
Ironically, once General Washington made the decision for mass inoculation, he encountered little actual resistance among the troops. However, throughout military history some service members have objected to compulsory vaccination on medical, religious, and personal grounds. In United States v Chadwell, a military court ruled against 2 Marine Corps members who refused vaccination for smallpox, typhoid, paratyphoid, and influenza, citing religious grounds. The court opined that the military orders that ensure the health and safety of the armed forces and thereby that of the public override personal religious beliefs.7
The paradox of liberty—the liberty first won in the Revolutionary War—is that in a pluralistic representative democracy like ours to secure the freedom for all, some, such as the military, must relinquish the very choice to refuse. Their sacrifices grant liberty to others. On June 6, we commemorated the seventy-fifth anniversary of D-Day, remembering how great the cost of that eternal vigilance, which the patriot Thomas Paine said was the price of liberty. On Memorial Day, we remember all those men and women who died in the service of their country. And while they gave up the most precious gift, we must never forget that every person in uniform also surrenders many other significant personal freedoms so that their fellow civilians may exercise them.
The question General Washington faced is one that public health authorities and our legislators again confront. When should the freedom to refuse, which was won with the blood of many valiant heroes and has been defended since 1776, be curtailed for the greater good? We are the one nation in history that has made the defense of self-determination its highest value and in so doing, its greatest challenge.
The disputes about those who decline to vaccinate their children for communicable infectious diseases, especially measles, have been in the headlines of late. Those refusals are often done in the name of “medical freedom.”1 Yet this is a much older debate for the military. It seems fitting in this month in which we celebrate the 243rd anniversary of the Declaration of Independence to reflect on the earliest history of the interaction between vaccinations and war in the US and what it tells us about the fight for religious and political freedom and individual liberty.
Go back in time with me to 1776, long before the Fourth of July was a day for barbecues and fireworks. We are in Boston, Philadelphia, and other important cities in colonial America. This time, concern was not about measles but the even more dreaded smallpox. In the first years of the Revolutionary War, General George Washington took command of a newly formed and named Continental Army. A catastrophic 90% of casualties in the Continental Army were from infectious diseases, with the lion’s share of these from smallpox, which at that time had a mortality rate of about 30%.2,3
Early efforts to introduce inoculation into the colonies had failed for many of the same reasons parents across the US today refuse immunization: fear and anxiety. When the renowned New England Puritan minister and scientist Cotton Mather attempted in 1721 to introduce variolation, his house was firebombed and his fellow clergy and physicians alleged that his efforts at inoculation were challenging God’s will to send a plague.3 Variolation was the now antiquated and then laborious process in which a previously unexposed individual was inoculated with material from the vesicle of someone infected with the disease.4,5 Variolation was practiced in parts of Africa and Asia and among wealthy Europeans but remained controversial in many colonies where few Americans had been exposed to smallpox or could afford the procedure.3
It is important to note that the use of variolation was practiced before Edward Jenner famously demonstrated that cowpox vaccine could provide immunity to smallpox in 1798. The majority of those inoculated would develop a mild case of smallpox that required a 5-week period of illness and recovery that provided lifelong immunity. However, during those 5 weeks, they remained a vector of disease for the uninoculated. Southern and New England colonies passed laws that prohibited variolation. Those anti-inoculation attitudes were the basis for the order given to the surgeons general of the Continental Army in 1776 that all inoculations of the troops were forbidden, despite the fact that perhaps only 25% of soldiers possessed any natural immunity.2,3
There was yet another reason that many colonial Americans opposed government-sponsored preventative care, and it was the same reason that they were fighting a war of independence: distrust and resentment of authority. The modern antivaccine movement voices similar fears and suspicions regarding public health campaigns and especially legislative efforts to mandate vaccinations or remove extant exemptions.
In 1775 in Boston, a smallpox outbreak occurred at the same time the Americans laid siege to the British troops occupying the city. Greater natural immunity to the scourge of smallpox either through exposure or variolation provided the British with a stronger defense than the mere city fortifications. There are even some suspicions that the British used the virus as a proto-biologic weapon.
General Washington had initially been against inoculation until he realized that without it the British might win the war. This possibility presented him with a momentous decision: inoculate despite widespread anxiety that variolation would spread the disease or risk the virus ravaging the fighting force. Perhaps the most compelling reason to variolate was that new recruits refused to sign up, fearing not that they would die in battle but of smallpox. In 1777, Washington mandated variolation of the nonimmune troops and new recruits, making it the first large-scale military preventative care measure in history.
Recapitulating an ethical dilemma that still rages in the military nearly 3 centuries later, for British soldiers, inoculation was voluntary not compulsory as for the Americans. There was so much opposition to Washington’s order that communications with surgeons were secret, and commanding officers had to oversee the inoculations.2,3
Washington’s policy not only contributed mightily to the American victory in the war, but also set the precedent for compulsory vaccination in the US military for the next 3 centuries. Currently, regulations require that service members be vaccinated for multiple infectious diseases. Of interest, this mandatory vaccination program has led to no reported cases of measles among military families to date, in part because of federal regulations requiring families of those service members to be vaccinated.6
Ironically, once General Washington made the decision for mass inoculation, he encountered little actual resistance among the troops. However, throughout military history some service members have objected to compulsory vaccination on medical, religious, and personal grounds. In United States v Chadwell, a military court ruled against 2 Marine Corps members who refused vaccination for smallpox, typhoid, paratyphoid, and influenza, citing religious grounds. The court opined that the military orders that ensure the health and safety of the armed forces and thereby that of the public override personal religious beliefs.7
The paradox of liberty—the liberty first won in the Revolutionary War—is that in a pluralistic representative democracy like ours to secure the freedom for all, some, such as the military, must relinquish the very choice to refuse. Their sacrifices grant liberty to others. On June 6, we commemorated the seventy-fifth anniversary of D-Day, remembering how great the cost of that eternal vigilance, which the patriot Thomas Paine said was the price of liberty. On Memorial Day, we remember all those men and women who died in the service of their country. And while they gave up the most precious gift, we must never forget that every person in uniform also surrenders many other significant personal freedoms so that their fellow civilians may exercise them.
The question General Washington faced is one that public health authorities and our legislators again confront. When should the freedom to refuse, which was won with the blood of many valiant heroes and has been defended since 1776, be curtailed for the greater good? We are the one nation in history that has made the defense of self-determination its highest value and in so doing, its greatest challenge.
1. Sun LH. Senate panel warns of dangers of ant-vaccine movement. https://www.washingtonpost.com/health/2019/03/05/combat-anti-vaxxers-us-needs-national-campaign-top-washington-state-official-says/?utm_term=.9a4201be0ed1. Published March 5, 2019. Accessed June 9, 2019.
2. Filsinger AL, Dwek R. George Washington and the first mass military inoculation. http://www.loc.gov/rr/scitech/GW&smallpoxinoculation.html. Published February 12, 2009. Accessed June 10, 2019.
3. Fenn EA. Pox Americana. New York: Hill and Wang; 2001.
4. Steadman’s Medical Dictionary. 28th edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2006.
5. Artenstein AW, Opal JM, Opal SM, Tramont EC, Georges P, Russell PK. History of U.S. military contributions to the study of vaccines and infectious diseases. Mil Med. 2005;170(suppl 4):3-11.
6. Jowers K. So far, no measles cases at military medical facilities—but officials are watching. https://www.militarytimes.com/pay-benefits/2019/04/19/so-far-no-measles-cases-at-military-medical-facilities-but-officials-are-watching/. Published April 19, 2019. Accessed June 9, 2019.
7. Cole JP, Swendiman KS. Mandatory vaccinations: precedent and current laws. https://fas.org/sgp/crs/misc/RS21414.pdf. Published May 21, 2014. Accessed June 10, 2019.
1. Sun LH. Senate panel warns of dangers of ant-vaccine movement. https://www.washingtonpost.com/health/2019/03/05/combat-anti-vaxxers-us-needs-national-campaign-top-washington-state-official-says/?utm_term=.9a4201be0ed1. Published March 5, 2019. Accessed June 9, 2019.
2. Filsinger AL, Dwek R. George Washington and the first mass military inoculation. http://www.loc.gov/rr/scitech/GW&smallpoxinoculation.html. Published February 12, 2009. Accessed June 10, 2019.
3. Fenn EA. Pox Americana. New York: Hill and Wang; 2001.
4. Steadman’s Medical Dictionary. 28th edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2006.
5. Artenstein AW, Opal JM, Opal SM, Tramont EC, Georges P, Russell PK. History of U.S. military contributions to the study of vaccines and infectious diseases. Mil Med. 2005;170(suppl 4):3-11.
6. Jowers K. So far, no measles cases at military medical facilities—but officials are watching. https://www.militarytimes.com/pay-benefits/2019/04/19/so-far-no-measles-cases-at-military-medical-facilities-but-officials-are-watching/. Published April 19, 2019. Accessed June 9, 2019.
7. Cole JP, Swendiman KS. Mandatory vaccinations: precedent and current laws. https://fas.org/sgp/crs/misc/RS21414.pdf. Published May 21, 2014. Accessed June 10, 2019.
Flu vaccine succeeds in TNF inhibitor users
MADRID – Influenza vaccination is similarly effective for individuals taking a tumor necrosis factor (TNF) inhibitor and healthy controls, but the number needed to vaccinate to prevent one case of influenza for patients taking a TNF inhibitor is much lower, according to data from a study presented at the European Congress of Rheumatology.
The number needed to vaccinate (NNV) to prevent one case of influenza among healthy control patients was 71, compared with an NNV of 10 for patients taking the TNF inhibitor adalimumab (Humira), reported Giovanni Adami, MD, and colleagues at the University of Verona (Italy).
While TNF inhibitors “are known to increase the risk of infection by suppressing the activity of the immune system,” it has not been clear whether the response to vaccination is impaired in patients treated with a TNF inhibitor, Dr. Adami said.
Dr. Adami and colleagues reviewed data from 15,132 adult patients exposed to adalimumab in global rheumatoid arthritis clinical trials and 71,221 healthy controls from clinical trials of influenza vaccines. Overall, the rate of influenza infection was similarly reduced with vaccination in both groups. The rate in healthy individuals went from 2.3% for those unvaccinated to 0.9% for those vaccinated; for TNF inhibitor–treated patients, the rate was 14.4% for those unvaccinated versus 4.5% for those vaccinated.
“It is not surprising that the number needed to vaccinate is dramatically lower in patients treated with immunosuppressors, compared to healthy individuals,” Dr. Adami noted. “As a matter of fact, patients treated with such drugs are at higher risk of infections, namely they have a greater absolute risk of influenza. Nevertheless, [it] is quite surprising that the relative risk reduction is similar between TNF inhibitor–treated patients and healthy controls, meaning that the vaccination is efficacious in both the cohorts.”
The researchers also calculated the cost to prevent one case of influenza, using a cost of approximately 16.5 euro per vaccine. (Dr. Adami also cited an average U.S. cost of about $40/vaccine). Using this method, they estimated a cost for vaccination of 1,174 euro (roughly $1,340) to prevent one influenza infection in the general population, and a cost of about 165 euro (roughly $188) to vaccinate enough people treated with a TNF inhibitor to prevent one infection.
Dr. Adami advised clinicians to remember the low NNV for TNF inhibitor–treated patients with regard to influenza vaccination. “A direct disclosure of the NNV for these patients might help adherence to vaccinations,” he said.
Next steps for research should include extending the real-world effectiveness analysis to other medications and other diseases, such as zoster vaccination in patients treated with Janus kinase inhibitors, Dr. Adami said.
Dr. Adami had no financial conflicts to disclose. Several coauthors disclosed relationships with companies including Abiogen Pharma, Grünenthal, Amgen, Janssen-Cilag, Mundipharma, and Pfizer.
Mitchel L. Zoler contributed to this report.
SOURCE: Adami G et al. Ann Rheum Dis. Jun 2019;78(Suppl 2):192-3. Abstract OP0230, doi: 10.1136/annrheumdis-2019-eular.3088
MADRID – Influenza vaccination is similarly effective for individuals taking a tumor necrosis factor (TNF) inhibitor and healthy controls, but the number needed to vaccinate to prevent one case of influenza for patients taking a TNF inhibitor is much lower, according to data from a study presented at the European Congress of Rheumatology.
The number needed to vaccinate (NNV) to prevent one case of influenza among healthy control patients was 71, compared with an NNV of 10 for patients taking the TNF inhibitor adalimumab (Humira), reported Giovanni Adami, MD, and colleagues at the University of Verona (Italy).
While TNF inhibitors “are known to increase the risk of infection by suppressing the activity of the immune system,” it has not been clear whether the response to vaccination is impaired in patients treated with a TNF inhibitor, Dr. Adami said.
Dr. Adami and colleagues reviewed data from 15,132 adult patients exposed to adalimumab in global rheumatoid arthritis clinical trials and 71,221 healthy controls from clinical trials of influenza vaccines. Overall, the rate of influenza infection was similarly reduced with vaccination in both groups. The rate in healthy individuals went from 2.3% for those unvaccinated to 0.9% for those vaccinated; for TNF inhibitor–treated patients, the rate was 14.4% for those unvaccinated versus 4.5% for those vaccinated.
“It is not surprising that the number needed to vaccinate is dramatically lower in patients treated with immunosuppressors, compared to healthy individuals,” Dr. Adami noted. “As a matter of fact, patients treated with such drugs are at higher risk of infections, namely they have a greater absolute risk of influenza. Nevertheless, [it] is quite surprising that the relative risk reduction is similar between TNF inhibitor–treated patients and healthy controls, meaning that the vaccination is efficacious in both the cohorts.”
The researchers also calculated the cost to prevent one case of influenza, using a cost of approximately 16.5 euro per vaccine. (Dr. Adami also cited an average U.S. cost of about $40/vaccine). Using this method, they estimated a cost for vaccination of 1,174 euro (roughly $1,340) to prevent one influenza infection in the general population, and a cost of about 165 euro (roughly $188) to vaccinate enough people treated with a TNF inhibitor to prevent one infection.
Dr. Adami advised clinicians to remember the low NNV for TNF inhibitor–treated patients with regard to influenza vaccination. “A direct disclosure of the NNV for these patients might help adherence to vaccinations,” he said.
Next steps for research should include extending the real-world effectiveness analysis to other medications and other diseases, such as zoster vaccination in patients treated with Janus kinase inhibitors, Dr. Adami said.
Dr. Adami had no financial conflicts to disclose. Several coauthors disclosed relationships with companies including Abiogen Pharma, Grünenthal, Amgen, Janssen-Cilag, Mundipharma, and Pfizer.
Mitchel L. Zoler contributed to this report.
SOURCE: Adami G et al. Ann Rheum Dis. Jun 2019;78(Suppl 2):192-3. Abstract OP0230, doi: 10.1136/annrheumdis-2019-eular.3088
MADRID – Influenza vaccination is similarly effective for individuals taking a tumor necrosis factor (TNF) inhibitor and healthy controls, but the number needed to vaccinate to prevent one case of influenza for patients taking a TNF inhibitor is much lower, according to data from a study presented at the European Congress of Rheumatology.
The number needed to vaccinate (NNV) to prevent one case of influenza among healthy control patients was 71, compared with an NNV of 10 for patients taking the TNF inhibitor adalimumab (Humira), reported Giovanni Adami, MD, and colleagues at the University of Verona (Italy).
While TNF inhibitors “are known to increase the risk of infection by suppressing the activity of the immune system,” it has not been clear whether the response to vaccination is impaired in patients treated with a TNF inhibitor, Dr. Adami said.
Dr. Adami and colleagues reviewed data from 15,132 adult patients exposed to adalimumab in global rheumatoid arthritis clinical trials and 71,221 healthy controls from clinical trials of influenza vaccines. Overall, the rate of influenza infection was similarly reduced with vaccination in both groups. The rate in healthy individuals went from 2.3% for those unvaccinated to 0.9% for those vaccinated; for TNF inhibitor–treated patients, the rate was 14.4% for those unvaccinated versus 4.5% for those vaccinated.
“It is not surprising that the number needed to vaccinate is dramatically lower in patients treated with immunosuppressors, compared to healthy individuals,” Dr. Adami noted. “As a matter of fact, patients treated with such drugs are at higher risk of infections, namely they have a greater absolute risk of influenza. Nevertheless, [it] is quite surprising that the relative risk reduction is similar between TNF inhibitor–treated patients and healthy controls, meaning that the vaccination is efficacious in both the cohorts.”
The researchers also calculated the cost to prevent one case of influenza, using a cost of approximately 16.5 euro per vaccine. (Dr. Adami also cited an average U.S. cost of about $40/vaccine). Using this method, they estimated a cost for vaccination of 1,174 euro (roughly $1,340) to prevent one influenza infection in the general population, and a cost of about 165 euro (roughly $188) to vaccinate enough people treated with a TNF inhibitor to prevent one infection.
Dr. Adami advised clinicians to remember the low NNV for TNF inhibitor–treated patients with regard to influenza vaccination. “A direct disclosure of the NNV for these patients might help adherence to vaccinations,” he said.
Next steps for research should include extending the real-world effectiveness analysis to other medications and other diseases, such as zoster vaccination in patients treated with Janus kinase inhibitors, Dr. Adami said.
Dr. Adami had no financial conflicts to disclose. Several coauthors disclosed relationships with companies including Abiogen Pharma, Grünenthal, Amgen, Janssen-Cilag, Mundipharma, and Pfizer.
Mitchel L. Zoler contributed to this report.
SOURCE: Adami G et al. Ann Rheum Dis. Jun 2019;78(Suppl 2):192-3. Abstract OP0230, doi: 10.1136/annrheumdis-2019-eular.3088
REPORTING FROM EULAR 2019 CONGRESS
Bridging the “Digital Divide”
The “digital divide”: That is how the VA describes the situation of the 42% of veterans without reliable—or any—Internet access. The lack of access means they are effectively barred from participating in telehealth and other online services.
With the goal of “digital inclusion,” the Veterans Health Administration (VHA) is partnering with a variety of nongovernmental businesses. VHA and T-Mobile, for instance, host the VA Video Connect application, which connects veterans to health care providers on a secure line on all devices with T-Mobile for free.
Walmart, Philips, and Veteran Service Organizations have set up remote clinics for veterans to access telehealth services closer to their home; with those partners, the VHA also lends Internet-connected iPads to veterans who do not have home computers.
Now, the VHA is working with Microsoft and Internet service providers to bring broadband access to rural areas with large populations of veterans.
The initiatives will not only improve access to health care, but also open other avenues. Dr. Kevin Galpin, executive director of VHA Telehealth Services, says, “We really want veterans to have the opportunities that come with being connected. There is lots of value in being able to maintain social relationships, conduct job searches online, and connect with VA. We know limited access is a problem and we’re exploring a multitude of options.”
The “digital divide”: That is how the VA describes the situation of the 42% of veterans without reliable—or any—Internet access. The lack of access means they are effectively barred from participating in telehealth and other online services.
With the goal of “digital inclusion,” the Veterans Health Administration (VHA) is partnering with a variety of nongovernmental businesses. VHA and T-Mobile, for instance, host the VA Video Connect application, which connects veterans to health care providers on a secure line on all devices with T-Mobile for free.
Walmart, Philips, and Veteran Service Organizations have set up remote clinics for veterans to access telehealth services closer to their home; with those partners, the VHA also lends Internet-connected iPads to veterans who do not have home computers.
Now, the VHA is working with Microsoft and Internet service providers to bring broadband access to rural areas with large populations of veterans.
The initiatives will not only improve access to health care, but also open other avenues. Dr. Kevin Galpin, executive director of VHA Telehealth Services, says, “We really want veterans to have the opportunities that come with being connected. There is lots of value in being able to maintain social relationships, conduct job searches online, and connect with VA. We know limited access is a problem and we’re exploring a multitude of options.”
The “digital divide”: That is how the VA describes the situation of the 42% of veterans without reliable—or any—Internet access. The lack of access means they are effectively barred from participating in telehealth and other online services.
With the goal of “digital inclusion,” the Veterans Health Administration (VHA) is partnering with a variety of nongovernmental businesses. VHA and T-Mobile, for instance, host the VA Video Connect application, which connects veterans to health care providers on a secure line on all devices with T-Mobile for free.
Walmart, Philips, and Veteran Service Organizations have set up remote clinics for veterans to access telehealth services closer to their home; with those partners, the VHA also lends Internet-connected iPads to veterans who do not have home computers.
Now, the VHA is working with Microsoft and Internet service providers to bring broadband access to rural areas with large populations of veterans.
The initiatives will not only improve access to health care, but also open other avenues. Dr. Kevin Galpin, executive director of VHA Telehealth Services, says, “We really want veterans to have the opportunities that come with being connected. There is lots of value in being able to maintain social relationships, conduct job searches online, and connect with VA. We know limited access is a problem and we’re exploring a multitude of options.”
Almost one-third of ED patients with gout are prescribed opioids
Patients with gout who visit the emergency department are regularly prescribed opioids, based on a review of electronic medical records.
“In addition to regulatory changes, the burden of opioid prescription could be potentially reduced by creating prompts for providers in electronic record systems to avoid prescribing opioids in opioid-naive patients or using lower intensity and shorter duration of prescription,” wrote Deepan S. Dalal, MD, of Brown University, Providence, R.I., and coauthors. The study was published in Arthritis Care & Research.
To determine frequency, dose, and duration of opioid prescription at ED discharge, the researchers reviewed the records of 456 patients with acute gout who were discharged in Rhode Island between March 30, 2015, and Sept. 30, 2017. All data were gathered via electronic medical system records.
Of the 456 discharged patients, 129 (28.3%) were prescribed opioids; 102 (79%) were not on opioids at the time. A full prescription description was available for 119 of the 129 patients; 96 (81%) were prescribed oxycodone or oxycodone combinations. Hydrocodone was prescribed for 9 patients (8%) and tramadol was prescribed for 11 patients (9%).
The median duration of each prescription was 8 days (interquartile range, 5-14 days) and the average daily dose was 37.9 mg of morphine equivalent. Patients who were prescribed opioids tended to be younger and male. After multivariable analysis, diabetes, polyarticular gout attack, and prior opioid use were all associated with a more than 100% higher odds of receiving an opioid prescription.
The authors acknowledged their study’s limitations, including their inability to determine the physicians’ reasoning behind each prescription or the prescribing habits of each provider. In addition, they were only able to assess the prescriptions as being written and not the number of pills actually taken or not taken.
No conflicts of interest were reported.
SOURCE: Dalal DS et al. Arthritis Care Res. 2019 Jul 3. doi: 10.1002/acr.23928.
Patients with gout who visit the emergency department are regularly prescribed opioids, based on a review of electronic medical records.
“In addition to regulatory changes, the burden of opioid prescription could be potentially reduced by creating prompts for providers in electronic record systems to avoid prescribing opioids in opioid-naive patients or using lower intensity and shorter duration of prescription,” wrote Deepan S. Dalal, MD, of Brown University, Providence, R.I., and coauthors. The study was published in Arthritis Care & Research.
To determine frequency, dose, and duration of opioid prescription at ED discharge, the researchers reviewed the records of 456 patients with acute gout who were discharged in Rhode Island between March 30, 2015, and Sept. 30, 2017. All data were gathered via electronic medical system records.
Of the 456 discharged patients, 129 (28.3%) were prescribed opioids; 102 (79%) were not on opioids at the time. A full prescription description was available for 119 of the 129 patients; 96 (81%) were prescribed oxycodone or oxycodone combinations. Hydrocodone was prescribed for 9 patients (8%) and tramadol was prescribed for 11 patients (9%).
The median duration of each prescription was 8 days (interquartile range, 5-14 days) and the average daily dose was 37.9 mg of morphine equivalent. Patients who were prescribed opioids tended to be younger and male. After multivariable analysis, diabetes, polyarticular gout attack, and prior opioid use were all associated with a more than 100% higher odds of receiving an opioid prescription.
The authors acknowledged their study’s limitations, including their inability to determine the physicians’ reasoning behind each prescription or the prescribing habits of each provider. In addition, they were only able to assess the prescriptions as being written and not the number of pills actually taken or not taken.
No conflicts of interest were reported.
SOURCE: Dalal DS et al. Arthritis Care Res. 2019 Jul 3. doi: 10.1002/acr.23928.
Patients with gout who visit the emergency department are regularly prescribed opioids, based on a review of electronic medical records.
“In addition to regulatory changes, the burden of opioid prescription could be potentially reduced by creating prompts for providers in electronic record systems to avoid prescribing opioids in opioid-naive patients or using lower intensity and shorter duration of prescription,” wrote Deepan S. Dalal, MD, of Brown University, Providence, R.I., and coauthors. The study was published in Arthritis Care & Research.
To determine frequency, dose, and duration of opioid prescription at ED discharge, the researchers reviewed the records of 456 patients with acute gout who were discharged in Rhode Island between March 30, 2015, and Sept. 30, 2017. All data were gathered via electronic medical system records.
Of the 456 discharged patients, 129 (28.3%) were prescribed opioids; 102 (79%) were not on opioids at the time. A full prescription description was available for 119 of the 129 patients; 96 (81%) were prescribed oxycodone or oxycodone combinations. Hydrocodone was prescribed for 9 patients (8%) and tramadol was prescribed for 11 patients (9%).
The median duration of each prescription was 8 days (interquartile range, 5-14 days) and the average daily dose was 37.9 mg of morphine equivalent. Patients who were prescribed opioids tended to be younger and male. After multivariable analysis, diabetes, polyarticular gout attack, and prior opioid use were all associated with a more than 100% higher odds of receiving an opioid prescription.
The authors acknowledged their study’s limitations, including their inability to determine the physicians’ reasoning behind each prescription or the prescribing habits of each provider. In addition, they were only able to assess the prescriptions as being written and not the number of pills actually taken or not taken.
No conflicts of interest were reported.
SOURCE: Dalal DS et al. Arthritis Care Res. 2019 Jul 3. doi: 10.1002/acr.23928.
FROM ARTHRITIS CARE & RESEARCH
Key clinical point: Though there are other effective conventional treatments, opioids are often prescribed for patients who present to the ED with gout.
Major finding: After multivariable analysis, diabetes, polyarticular gout attack, and prior opioid use were all associated with a more than 100% higher odds of opioid prescription.
Study details: A retrospective cohort study of 456 patients with acute gout discharged from EDs in Rhode Island.
Disclosures: The authors reported no conflicts of interest.
Source: Dalal DS et al. Arthritis Care Res. 2019 Jul 3. doi: 10.1002/acr.23928.
VIDEO: Did You Know? Psoriasis and quality of life



Probiotics tied to reduced cognitive reactivity in mild, moderate depression
The consumption of some probiotic supplements appears linked to a reduced susceptibility to depressive symptoms, preliminary results of a randomized trial of 71 participants show.
“Results from the current study provide further evidence that some probiotic mixtures can influence thinking and cognition,” reported Bahia Chahwan of the University of Technology Sydney in New South Wales, Australia, and associates. “Although probiotics did not appear to have had a direct effect on depressive symptoms, our results suggest that probiotics potentially act on cognitive processes contributing to depression.” The study was published in the Journal of Affective Disorders.
To conduct the study, the investigators recruited 71 adults over a 12-month period. A nondepressed control group consisting of 20 adults was recruited over 2 months. Across both groups, about 70% of the participants were women, 67% were white, 80% had no abdominal conditions, 78% did not smoke, and 92% did not consume alcohol above the daily recommended intake. The participants were randomly assigned to either the probiotic or placebo group. Members of both groups received instructions on how to consume their respective product, which was a 2-g freeze-dried powder mixture, twice a day over 8 weeks, and were scheduled for weekly monitoring visits.
Several pre- and postintervention measures of depression were compared using several scales, including the MINI International Neuropsychiatric Interview, the Depression Anxiety Stress Scale-21, and the Beck Anxiety Inventory.
Participants in both groups experienced a reduction in depressive symptoms during the trial period. “This is in line with the evidence suggesting that
However, in contrast to the investigators’ hypotheses, participants in the probiotics group did not experience a greater reduction in depressive symptoms than did those on placebo. Instead, the differences between the groups were seen on a measure for depression called cognitive reactivity. Specifically, people with mild/moderate depression who took the probiotics reported lower psychological test scores on cognitive reactivity, compared with controls (45.00 vs. 53.78).
Additional research is needed to look at the impact of differences in gut microbiota strains on people with depressive symptoms, the researchers said. In the meantime, clinicians might do well to consider probiotics as an adjunctive intervention. “Probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT, which changes cognitive patterns.”
One of the authors, Saskia van Hemert, is an employee of Winclove Probiotics. The other authors reported having no conflicts of interest.
SOURCE: Chahwan B et al. J Affect Disord. 2019. doi: 10.1016/j.jad.2019.04.97.
The consumption of some probiotic supplements appears linked to a reduced susceptibility to depressive symptoms, preliminary results of a randomized trial of 71 participants show.
“Results from the current study provide further evidence that some probiotic mixtures can influence thinking and cognition,” reported Bahia Chahwan of the University of Technology Sydney in New South Wales, Australia, and associates. “Although probiotics did not appear to have had a direct effect on depressive symptoms, our results suggest that probiotics potentially act on cognitive processes contributing to depression.” The study was published in the Journal of Affective Disorders.
To conduct the study, the investigators recruited 71 adults over a 12-month period. A nondepressed control group consisting of 20 adults was recruited over 2 months. Across both groups, about 70% of the participants were women, 67% were white, 80% had no abdominal conditions, 78% did not smoke, and 92% did not consume alcohol above the daily recommended intake. The participants were randomly assigned to either the probiotic or placebo group. Members of both groups received instructions on how to consume their respective product, which was a 2-g freeze-dried powder mixture, twice a day over 8 weeks, and were scheduled for weekly monitoring visits.
Several pre- and postintervention measures of depression were compared using several scales, including the MINI International Neuropsychiatric Interview, the Depression Anxiety Stress Scale-21, and the Beck Anxiety Inventory.
Participants in both groups experienced a reduction in depressive symptoms during the trial period. “This is in line with the evidence suggesting that
However, in contrast to the investigators’ hypotheses, participants in the probiotics group did not experience a greater reduction in depressive symptoms than did those on placebo. Instead, the differences between the groups were seen on a measure for depression called cognitive reactivity. Specifically, people with mild/moderate depression who took the probiotics reported lower psychological test scores on cognitive reactivity, compared with controls (45.00 vs. 53.78).
Additional research is needed to look at the impact of differences in gut microbiota strains on people with depressive symptoms, the researchers said. In the meantime, clinicians might do well to consider probiotics as an adjunctive intervention. “Probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT, which changes cognitive patterns.”
One of the authors, Saskia van Hemert, is an employee of Winclove Probiotics. The other authors reported having no conflicts of interest.
SOURCE: Chahwan B et al. J Affect Disord. 2019. doi: 10.1016/j.jad.2019.04.97.
The consumption of some probiotic supplements appears linked to a reduced susceptibility to depressive symptoms, preliminary results of a randomized trial of 71 participants show.
“Results from the current study provide further evidence that some probiotic mixtures can influence thinking and cognition,” reported Bahia Chahwan of the University of Technology Sydney in New South Wales, Australia, and associates. “Although probiotics did not appear to have had a direct effect on depressive symptoms, our results suggest that probiotics potentially act on cognitive processes contributing to depression.” The study was published in the Journal of Affective Disorders.
To conduct the study, the investigators recruited 71 adults over a 12-month period. A nondepressed control group consisting of 20 adults was recruited over 2 months. Across both groups, about 70% of the participants were women, 67% were white, 80% had no abdominal conditions, 78% did not smoke, and 92% did not consume alcohol above the daily recommended intake. The participants were randomly assigned to either the probiotic or placebo group. Members of both groups received instructions on how to consume their respective product, which was a 2-g freeze-dried powder mixture, twice a day over 8 weeks, and were scheduled for weekly monitoring visits.
Several pre- and postintervention measures of depression were compared using several scales, including the MINI International Neuropsychiatric Interview, the Depression Anxiety Stress Scale-21, and the Beck Anxiety Inventory.
Participants in both groups experienced a reduction in depressive symptoms during the trial period. “This is in line with the evidence suggesting that
However, in contrast to the investigators’ hypotheses, participants in the probiotics group did not experience a greater reduction in depressive symptoms than did those on placebo. Instead, the differences between the groups were seen on a measure for depression called cognitive reactivity. Specifically, people with mild/moderate depression who took the probiotics reported lower psychological test scores on cognitive reactivity, compared with controls (45.00 vs. 53.78).
Additional research is needed to look at the impact of differences in gut microbiota strains on people with depressive symptoms, the researchers said. In the meantime, clinicians might do well to consider probiotics as an adjunctive intervention. “Probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT, which changes cognitive patterns.”
One of the authors, Saskia van Hemert, is an employee of Winclove Probiotics. The other authors reported having no conflicts of interest.
SOURCE: Chahwan B et al. J Affect Disord. 2019. doi: 10.1016/j.jad.2019.04.97.
FROM THE JOURNAL OF AFFECTIVE DISORDERS
Sleepiest OSA patients have worse CV outcomes
SAN ANTONIO – Patients with obstructive sleep apnea who complain of feeling tired when they wake up, being sleepy during the day, and have a high score on the Epworth Sleepiness Scale face an increased risk for cardiovascular disease, results from a population-based analysis suggest.
“OSA is a highly heterogeneous disease, with multiple clinical presentations and consequences,” the study’s first author, Diego R. Mazzotti, PhD, said at the annual meeting of the Associated Professional Sleep Societies. “These patients also have diverse comorbidities, and there are arbitrary severity definitions and variable therapeutic responses. It’s difficult to lump these patients together.”
Symptom subtypes of OSA were originally described in the Icelandic Sleep Apnea Cohort, and defined as excessively sleepy, minimally symptomatic, and disturbed sleep (Eur Respir J. 2014; 44[6]:1600-7). These distinct clusters were identified based on symptom experiences and the existence of major comorbidities. “This concept is more popular today, trying to identify symptom clusters, or groups of individuals, that share similar polysomnographic data, and then compare differences in prevalence or incidence of cardiovascular disease,” said Dr. Mazzotti, a research associate at the University of Pennsylvania, Philadelphia. “That’s a concept that needs to be moving forward.”
Dr. Mazzotti and colleagues set out to determine if OSA symptom subtypes are present in the Sleep Heart Health Study, a multicenter, prospective, community-based cohort of individuals aged 40 years and older designed to assess the cardiovascular (CV) consequences of OSA. They also wanted to know if there is additional evidence of the relevance of OSA symptom subtypes, particularly with respect to cardiovascular disease .
Participant-reported symptoms, such as difficulty falling and staying asleep, snoring, fatigue, drowsy driving and daytime sleepiness, and responses to the Epworth Sleepiness Scale were used to determine the patient’s subtype. Assessments including questionnaires and in-home polysomnography were conducted at baseline (between 1995 and 1998) and follow-up (between 2001 and 2003), while CV outcomes were assessed until the end of follow-up (between 2008 and 2011).
In all, 1,207 patients from the Sleep Heart Health Study met criteria for moderate to severe OSA (apnea-hypopnea index, or AHI, of 15 or greater) and were included in the final analysis. They were followed for a mean of 12 years. Based on the clustering of symptoms, the researchers identified four OSA symptom subtypes: disturbed sleep (12%), minimally symptomatic (33%), excessively sleepy (17%), and moderately sleepy (38%) – proportions that were similar to those observed in prior studies.
The disturbed sleep subtype presented with increased prevalence of “insomnialike” symptoms, such as difficulty initiating or maintaining sleep, according to Dr. Mazzotti. “On the other hand, the excessively sleepy subtype presented with a very high prevalence of several symptoms related to excessive daytime sleepiness, while the moderately sleepy showed a moderately high prevalence of such symptoms, but not as much when compared to the excessively sleepy subtype,” he explained. “Finally, the minimally symptomatic subtype was found to have the lowest prevalence of all investigated symptoms, suggesting that these patients have low symptom burden. They do not complain as much, even though they have moderate-to-severe OSA.”
Next, Dr. Mazzotti and colleagues used Kaplan-Meier survival analysis and Cox proportional hazards models to evaluate whether subtypes were associated with incident coronary heart disease (CHD), heart failure, and CV disease, including CV mortality. Similar analyses were performed comparing each symptom subtype with 2,830 individuals without OSA (AHI less than 5).
Compared with other subtypes, the excessively sleepy group had a more than threefold increased odds of prevalent heart failure, after adjustment for other CV risk factors. They also had a 1.7- to 2.3-fold increased risk for incident CV disease (P less than .001), CHD (P = .015) and heart failure (P = 0.018), after adjustment for other CV risk factors.
“Compared to individuals without OSA, the excessively sleepy subtype is the only subtype with increased risk of incident CV disease and CHD,” Dr. Mazzotti said. “It is possible that excessively sleepy OSA patients are more likely to benefit from CPAP therapy in preventing CV disease.” These results were published online earlier this year (Am J Respir Crit Care Med. 2019 Feb 15. doi: 10.1164/rccm.201808-1509OC).
Dr. Mazzotti reported having no financial disclosures.
SOURCE: Mazzotti D et al. SLEEP 2019, Abstract 0586.
SAN ANTONIO – Patients with obstructive sleep apnea who complain of feeling tired when they wake up, being sleepy during the day, and have a high score on the Epworth Sleepiness Scale face an increased risk for cardiovascular disease, results from a population-based analysis suggest.
“OSA is a highly heterogeneous disease, with multiple clinical presentations and consequences,” the study’s first author, Diego R. Mazzotti, PhD, said at the annual meeting of the Associated Professional Sleep Societies. “These patients also have diverse comorbidities, and there are arbitrary severity definitions and variable therapeutic responses. It’s difficult to lump these patients together.”
Symptom subtypes of OSA were originally described in the Icelandic Sleep Apnea Cohort, and defined as excessively sleepy, minimally symptomatic, and disturbed sleep (Eur Respir J. 2014; 44[6]:1600-7). These distinct clusters were identified based on symptom experiences and the existence of major comorbidities. “This concept is more popular today, trying to identify symptom clusters, or groups of individuals, that share similar polysomnographic data, and then compare differences in prevalence or incidence of cardiovascular disease,” said Dr. Mazzotti, a research associate at the University of Pennsylvania, Philadelphia. “That’s a concept that needs to be moving forward.”
Dr. Mazzotti and colleagues set out to determine if OSA symptom subtypes are present in the Sleep Heart Health Study, a multicenter, prospective, community-based cohort of individuals aged 40 years and older designed to assess the cardiovascular (CV) consequences of OSA. They also wanted to know if there is additional evidence of the relevance of OSA symptom subtypes, particularly with respect to cardiovascular disease .
Participant-reported symptoms, such as difficulty falling and staying asleep, snoring, fatigue, drowsy driving and daytime sleepiness, and responses to the Epworth Sleepiness Scale were used to determine the patient’s subtype. Assessments including questionnaires and in-home polysomnography were conducted at baseline (between 1995 and 1998) and follow-up (between 2001 and 2003), while CV outcomes were assessed until the end of follow-up (between 2008 and 2011).
In all, 1,207 patients from the Sleep Heart Health Study met criteria for moderate to severe OSA (apnea-hypopnea index, or AHI, of 15 or greater) and were included in the final analysis. They were followed for a mean of 12 years. Based on the clustering of symptoms, the researchers identified four OSA symptom subtypes: disturbed sleep (12%), minimally symptomatic (33%), excessively sleepy (17%), and moderately sleepy (38%) – proportions that were similar to those observed in prior studies.
The disturbed sleep subtype presented with increased prevalence of “insomnialike” symptoms, such as difficulty initiating or maintaining sleep, according to Dr. Mazzotti. “On the other hand, the excessively sleepy subtype presented with a very high prevalence of several symptoms related to excessive daytime sleepiness, while the moderately sleepy showed a moderately high prevalence of such symptoms, but not as much when compared to the excessively sleepy subtype,” he explained. “Finally, the minimally symptomatic subtype was found to have the lowest prevalence of all investigated symptoms, suggesting that these patients have low symptom burden. They do not complain as much, even though they have moderate-to-severe OSA.”
Next, Dr. Mazzotti and colleagues used Kaplan-Meier survival analysis and Cox proportional hazards models to evaluate whether subtypes were associated with incident coronary heart disease (CHD), heart failure, and CV disease, including CV mortality. Similar analyses were performed comparing each symptom subtype with 2,830 individuals without OSA (AHI less than 5).
Compared with other subtypes, the excessively sleepy group had a more than threefold increased odds of prevalent heart failure, after adjustment for other CV risk factors. They also had a 1.7- to 2.3-fold increased risk for incident CV disease (P less than .001), CHD (P = .015) and heart failure (P = 0.018), after adjustment for other CV risk factors.
“Compared to individuals without OSA, the excessively sleepy subtype is the only subtype with increased risk of incident CV disease and CHD,” Dr. Mazzotti said. “It is possible that excessively sleepy OSA patients are more likely to benefit from CPAP therapy in preventing CV disease.” These results were published online earlier this year (Am J Respir Crit Care Med. 2019 Feb 15. doi: 10.1164/rccm.201808-1509OC).
Dr. Mazzotti reported having no financial disclosures.
SOURCE: Mazzotti D et al. SLEEP 2019, Abstract 0586.
SAN ANTONIO – Patients with obstructive sleep apnea who complain of feeling tired when they wake up, being sleepy during the day, and have a high score on the Epworth Sleepiness Scale face an increased risk for cardiovascular disease, results from a population-based analysis suggest.
“OSA is a highly heterogeneous disease, with multiple clinical presentations and consequences,” the study’s first author, Diego R. Mazzotti, PhD, said at the annual meeting of the Associated Professional Sleep Societies. “These patients also have diverse comorbidities, and there are arbitrary severity definitions and variable therapeutic responses. It’s difficult to lump these patients together.”
Symptom subtypes of OSA were originally described in the Icelandic Sleep Apnea Cohort, and defined as excessively sleepy, minimally symptomatic, and disturbed sleep (Eur Respir J. 2014; 44[6]:1600-7). These distinct clusters were identified based on symptom experiences and the existence of major comorbidities. “This concept is more popular today, trying to identify symptom clusters, or groups of individuals, that share similar polysomnographic data, and then compare differences in prevalence or incidence of cardiovascular disease,” said Dr. Mazzotti, a research associate at the University of Pennsylvania, Philadelphia. “That’s a concept that needs to be moving forward.”
Dr. Mazzotti and colleagues set out to determine if OSA symptom subtypes are present in the Sleep Heart Health Study, a multicenter, prospective, community-based cohort of individuals aged 40 years and older designed to assess the cardiovascular (CV) consequences of OSA. They also wanted to know if there is additional evidence of the relevance of OSA symptom subtypes, particularly with respect to cardiovascular disease .
Participant-reported symptoms, such as difficulty falling and staying asleep, snoring, fatigue, drowsy driving and daytime sleepiness, and responses to the Epworth Sleepiness Scale were used to determine the patient’s subtype. Assessments including questionnaires and in-home polysomnography were conducted at baseline (between 1995 and 1998) and follow-up (between 2001 and 2003), while CV outcomes were assessed until the end of follow-up (between 2008 and 2011).
In all, 1,207 patients from the Sleep Heart Health Study met criteria for moderate to severe OSA (apnea-hypopnea index, or AHI, of 15 or greater) and were included in the final analysis. They were followed for a mean of 12 years. Based on the clustering of symptoms, the researchers identified four OSA symptom subtypes: disturbed sleep (12%), minimally symptomatic (33%), excessively sleepy (17%), and moderately sleepy (38%) – proportions that were similar to those observed in prior studies.
The disturbed sleep subtype presented with increased prevalence of “insomnialike” symptoms, such as difficulty initiating or maintaining sleep, according to Dr. Mazzotti. “On the other hand, the excessively sleepy subtype presented with a very high prevalence of several symptoms related to excessive daytime sleepiness, while the moderately sleepy showed a moderately high prevalence of such symptoms, but not as much when compared to the excessively sleepy subtype,” he explained. “Finally, the minimally symptomatic subtype was found to have the lowest prevalence of all investigated symptoms, suggesting that these patients have low symptom burden. They do not complain as much, even though they have moderate-to-severe OSA.”
Next, Dr. Mazzotti and colleagues used Kaplan-Meier survival analysis and Cox proportional hazards models to evaluate whether subtypes were associated with incident coronary heart disease (CHD), heart failure, and CV disease, including CV mortality. Similar analyses were performed comparing each symptom subtype with 2,830 individuals without OSA (AHI less than 5).
Compared with other subtypes, the excessively sleepy group had a more than threefold increased odds of prevalent heart failure, after adjustment for other CV risk factors. They also had a 1.7- to 2.3-fold increased risk for incident CV disease (P less than .001), CHD (P = .015) and heart failure (P = 0.018), after adjustment for other CV risk factors.
“Compared to individuals without OSA, the excessively sleepy subtype is the only subtype with increased risk of incident CV disease and CHD,” Dr. Mazzotti said. “It is possible that excessively sleepy OSA patients are more likely to benefit from CPAP therapy in preventing CV disease.” These results were published online earlier this year (Am J Respir Crit Care Med. 2019 Feb 15. doi: 10.1164/rccm.201808-1509OC).
Dr. Mazzotti reported having no financial disclosures.
SOURCE: Mazzotti D et al. SLEEP 2019, Abstract 0586.
REPORTING FROM SLEEP 2019
FDA warning letters fall on Trump’s watch
according to findings from an analysis of public records sponsored by Science magazine and published July 2.
From Jan. 20, 2017, (President Trump’s inauguration day) through May 22, 2019, FDA sent out 1,033 warning letters, compared with 1,532 warning letters sent during the 28 months ending just before the inauguration, a drop of 33%, wrote Charles Piller, an investigative journalist on the Science staff (Science. 2019 Jul 2. doi: 10.1126/science.aay5859). Also during January 2017–May 2019, “official action indicated” reports, described by Mr. Piller as a frequent precursor to warning letters, fell by 45%, from 1,879 during the final 28 months of the Obama administration to 1,040 during the first 28 months of the Trump administration. The incidence of an injunction, characterized by Mr. Piller as a ”more forceful” step than a warning letter, was 35 during the 28 months before Donald Trump became president and 26 during the 28 months after, a relative 26% decline.
More detailed numbers in the report included a 33% drop in warning letters from the FDA center that deals with tobacco products, a 37% drop in warning letters from the center that deals with food safety, and a 72% fall in letters sent from the Center for Devices & Radiological Health. However the FDA Center for Drug Evaluation & Research sent 62% more warning letters (188) during the first 28 months after Donald Trump became president, compared with the final 28 months under President Obama, when it sent 116 warning letters. A year-by-year analysis that started in 2009 showed that warning letters peaked at about 800 per year during both 2011 and 2012, and then showed a steady decline during all subsequent years, falling to a rate during the first months of 2019 that projected to an annualized rate of 385 total warning letters sent by the end of this year.
In response to publication of these findings, FDA Media Relations Director Angela Stark said “the way the data are presented in the story does not accurately reflect FDA’s overarching work to protect the public health. While one publicly visible measure of FDA action, it’s important to understand that warning letters are just one action the FDA takes to seek compliance. The FDA has several tools at its disposal to work with a company to ensure compliance, such as through regulatory meetings with companies; untitled letters; follow-up inspections; and other regulatory and compliance measures depending on the situation, and we often do much of this behind the scenes in the interest of patient safety. Our use of any one enforcement tool may fluctuate year to year based on a number of factors, including the FDA’s assessment of the violations uncovered during the course of inspections, along with additional product-monitoring efforts.”
Ms. Stark also noted that, in some FDA centers, warning letters may have decreased “because the FDA has increased its interactions with industry to resolve issues, which often achieves more timely and effective corrective action.”
She also highlighted 1,300 warning letter and monetary penalty complaints sent to retailers since September 2018 over illegal sales of e-cigarettes to minors, “tens of thousands” of warning letters sent to tobacco retailers since the start of 2017 over other tobacco-related issues, and actions against stem-cell clinics that have marketed unapproved treatments.
[email protected]
SOURCE: Piller C. Science. 2019 Jul 2. doi: 10.1126/science.aay5859)
according to findings from an analysis of public records sponsored by Science magazine and published July 2.
From Jan. 20, 2017, (President Trump’s inauguration day) through May 22, 2019, FDA sent out 1,033 warning letters, compared with 1,532 warning letters sent during the 28 months ending just before the inauguration, a drop of 33%, wrote Charles Piller, an investigative journalist on the Science staff (Science. 2019 Jul 2. doi: 10.1126/science.aay5859). Also during January 2017–May 2019, “official action indicated” reports, described by Mr. Piller as a frequent precursor to warning letters, fell by 45%, from 1,879 during the final 28 months of the Obama administration to 1,040 during the first 28 months of the Trump administration. The incidence of an injunction, characterized by Mr. Piller as a ”more forceful” step than a warning letter, was 35 during the 28 months before Donald Trump became president and 26 during the 28 months after, a relative 26% decline.
More detailed numbers in the report included a 33% drop in warning letters from the FDA center that deals with tobacco products, a 37% drop in warning letters from the center that deals with food safety, and a 72% fall in letters sent from the Center for Devices & Radiological Health. However the FDA Center for Drug Evaluation & Research sent 62% more warning letters (188) during the first 28 months after Donald Trump became president, compared with the final 28 months under President Obama, when it sent 116 warning letters. A year-by-year analysis that started in 2009 showed that warning letters peaked at about 800 per year during both 2011 and 2012, and then showed a steady decline during all subsequent years, falling to a rate during the first months of 2019 that projected to an annualized rate of 385 total warning letters sent by the end of this year.
In response to publication of these findings, FDA Media Relations Director Angela Stark said “the way the data are presented in the story does not accurately reflect FDA’s overarching work to protect the public health. While one publicly visible measure of FDA action, it’s important to understand that warning letters are just one action the FDA takes to seek compliance. The FDA has several tools at its disposal to work with a company to ensure compliance, such as through regulatory meetings with companies; untitled letters; follow-up inspections; and other regulatory and compliance measures depending on the situation, and we often do much of this behind the scenes in the interest of patient safety. Our use of any one enforcement tool may fluctuate year to year based on a number of factors, including the FDA’s assessment of the violations uncovered during the course of inspections, along with additional product-monitoring efforts.”
Ms. Stark also noted that, in some FDA centers, warning letters may have decreased “because the FDA has increased its interactions with industry to resolve issues, which often achieves more timely and effective corrective action.”
She also highlighted 1,300 warning letter and monetary penalty complaints sent to retailers since September 2018 over illegal sales of e-cigarettes to minors, “tens of thousands” of warning letters sent to tobacco retailers since the start of 2017 over other tobacco-related issues, and actions against stem-cell clinics that have marketed unapproved treatments.
[email protected]
SOURCE: Piller C. Science. 2019 Jul 2. doi: 10.1126/science.aay5859)
according to findings from an analysis of public records sponsored by Science magazine and published July 2.
From Jan. 20, 2017, (President Trump’s inauguration day) through May 22, 2019, FDA sent out 1,033 warning letters, compared with 1,532 warning letters sent during the 28 months ending just before the inauguration, a drop of 33%, wrote Charles Piller, an investigative journalist on the Science staff (Science. 2019 Jul 2. doi: 10.1126/science.aay5859). Also during January 2017–May 2019, “official action indicated” reports, described by Mr. Piller as a frequent precursor to warning letters, fell by 45%, from 1,879 during the final 28 months of the Obama administration to 1,040 during the first 28 months of the Trump administration. The incidence of an injunction, characterized by Mr. Piller as a ”more forceful” step than a warning letter, was 35 during the 28 months before Donald Trump became president and 26 during the 28 months after, a relative 26% decline.
More detailed numbers in the report included a 33% drop in warning letters from the FDA center that deals with tobacco products, a 37% drop in warning letters from the center that deals with food safety, and a 72% fall in letters sent from the Center for Devices & Radiological Health. However the FDA Center for Drug Evaluation & Research sent 62% more warning letters (188) during the first 28 months after Donald Trump became president, compared with the final 28 months under President Obama, when it sent 116 warning letters. A year-by-year analysis that started in 2009 showed that warning letters peaked at about 800 per year during both 2011 and 2012, and then showed a steady decline during all subsequent years, falling to a rate during the first months of 2019 that projected to an annualized rate of 385 total warning letters sent by the end of this year.
In response to publication of these findings, FDA Media Relations Director Angela Stark said “the way the data are presented in the story does not accurately reflect FDA’s overarching work to protect the public health. While one publicly visible measure of FDA action, it’s important to understand that warning letters are just one action the FDA takes to seek compliance. The FDA has several tools at its disposal to work with a company to ensure compliance, such as through regulatory meetings with companies; untitled letters; follow-up inspections; and other regulatory and compliance measures depending on the situation, and we often do much of this behind the scenes in the interest of patient safety. Our use of any one enforcement tool may fluctuate year to year based on a number of factors, including the FDA’s assessment of the violations uncovered during the course of inspections, along with additional product-monitoring efforts.”
Ms. Stark also noted that, in some FDA centers, warning letters may have decreased “because the FDA has increased its interactions with industry to resolve issues, which often achieves more timely and effective corrective action.”
She also highlighted 1,300 warning letter and monetary penalty complaints sent to retailers since September 2018 over illegal sales of e-cigarettes to minors, “tens of thousands” of warning letters sent to tobacco retailers since the start of 2017 over other tobacco-related issues, and actions against stem-cell clinics that have marketed unapproved treatments.
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SOURCE: Piller C. Science. 2019 Jul 2. doi: 10.1126/science.aay5859)
FROM SCIENCE