Drug Therapy

To the Editor: We read with interest the article by Cikach et al on thoracic aortic aneurysm.¹ For medical management of this condition, the authors emphasized controlling blood pressure and heart rate and also avoiding isometric exercises and heavy lifting. In addition to their recommendations, we believe there is plausible evidence to advise caution if fluoroquinolone antibiotics are used in this setting.

Three large population-based studies, from Canada,² Taiwan,³ and Sweden,⁴ collectively demonstrated a significant 2-fold increase in the incidence of aortic aneurysm and dissection presenting within 60 days of fluoroquinolone use compared with other antibiotic exposure. Moreover, a longer duration of fluoroquinolone use was associated with a significantly higher incidence of aortic aneurysm and dissection.³

Mechanistically, fluoroquinolones have been shown to up-regulate production of several matrix metalloproteinases, including metalloproteinase 2, leading to degradation of type I collagen.^2,5 Type I and type III are the dominant collagens in the aortic wall, and collagen degradation is implicated in aortic aneurysm formation and expansion.

Fluoroquinolones are widely prescribed in both outpatient and inpatient settings and are sometimes used for long durations in the geriatric population.² It is possible that these drugs have a propensity to increase aortic aneurysm expansion and dissection in older patients who already have aortic aneurysm. Accordingly, this might make the risk-benefit ratio unfavorable for using these drugs in these situations, and other antibiotics should be used, if indicated.

Furthermore, if fluoroquinolones are used in patients with aortic aneurysm, perhaps imaging studies of the aneurysm should be done more frequently than once a year to detect accelerated aneurysm growth. Finally, physicians should be aware of the possibility of increased aortic aneurysm expansion and dissection with fluoroquinolone use.

To the Editor: We read with interest the article by Cikach et al on thoracic aortic aneurysm.¹ For medical management of this condition, the authors emphasized controlling blood pressure and heart rate and also avoiding isometric exercises and heavy lifting. In addition to their recommendations, we believe there is plausible evidence to advise caution if fluoroquinolone antibiotics are used in this setting.

Three large population-based studies, from Canada,² Taiwan,³ and Sweden,⁴ collectively demonstrated a significant 2-fold increase in the incidence of aortic aneurysm and dissection presenting within 60 days of fluoroquinolone use compared with other antibiotic exposure. Moreover, a longer duration of fluoroquinolone use was associated with a significantly higher incidence of aortic aneurysm and dissection.³

Mechanistically, fluoroquinolones have been shown to up-regulate production of several matrix metalloproteinases, including metalloproteinase 2, leading to degradation of type I collagen.^2,5 Type I and type III are the dominant collagens in the aortic wall, and collagen degradation is implicated in aortic aneurysm formation and expansion.

Fluoroquinolones are widely prescribed in both outpatient and inpatient settings and are sometimes used for long durations in the geriatric population.² It is possible that these drugs have a propensity to increase aortic aneurysm expansion and dissection in older patients who already have aortic aneurysm. Accordingly, this might make the risk-benefit ratio unfavorable for using these drugs in these situations, and other antibiotics should be used, if indicated.

Furthermore, if fluoroquinolones are used in patients with aortic aneurysm, perhaps imaging studies of the aneurysm should be done more frequently than once a year to detect accelerated aneurysm growth. Finally, physicians should be aware of the possibility of increased aortic aneurysm expansion and dissection with fluoroquinolone use.

To the Editor: We read with interest the article by Cikach et al on thoracic aortic aneurysm.¹ For medical management of this condition, the authors emphasized controlling blood pressure and heart rate and also avoiding isometric exercises and heavy lifting. In addition to their recommendations, we believe there is plausible evidence to advise caution if fluoroquinolone antibiotics are used in this setting.

Three large population-based studies, from Canada,² Taiwan,³ and Sweden,⁴ collectively demonstrated a significant 2-fold increase in the incidence of aortic aneurysm and dissection presenting within 60 days of fluoroquinolone use compared with other antibiotic exposure. Moreover, a longer duration of fluoroquinolone use was associated with a significantly higher incidence of aortic aneurysm and dissection.³

Mechanistically, fluoroquinolones have been shown to up-regulate production of several matrix metalloproteinases, including metalloproteinase 2, leading to degradation of type I collagen.^2,5 Type I and type III are the dominant collagens in the aortic wall, and collagen degradation is implicated in aortic aneurysm formation and expansion.

Fluoroquinolones are widely prescribed in both outpatient and inpatient settings and are sometimes used for long durations in the geriatric population.² It is possible that these drugs have a propensity to increase aortic aneurysm expansion and dissection in older patients who already have aortic aneurysm. Accordingly, this might make the risk-benefit ratio unfavorable for using these drugs in these situations, and other antibiotics should be used, if indicated.

Furthermore, if fluoroquinolones are used in patients with aortic aneurysm, perhaps imaging studies of the aneurysm should be done more frequently than once a year to detect accelerated aneurysm growth. Finally, physicians should be aware of the possibility of increased aortic aneurysm expansion and dissection with fluoroquinolone use.

In Reply: We thank Drs. Goldstein and Mascitelli for their comments regarding fluoroquinolones and thoracic aortic aneurysms. We acknowledge that fluoroquinolones (particularly ciprofloxacin) have been associated with a risk of aortic aneurysm and dissection based on large observational studies from Taiwan, Canada, and Sweden. Although all of the studies have shown an association between ciprofloxacin and aortic aneurysm, the causative role is not well established. In addition, the numbers of events were very small in these large cohorts of patients. In our large tertiary care practice at Cleveland Clinic, we have very few patients with aortic aneurysm or dissection who have used fluoroquinolones.

We recognize the association; however, our paper was intended to emphasize the more common causes and treatment options that primary care physicians are likely to encounter in routine practice.

We also thank Drs. Ayoubieh and MacCarrick for their comments about genetic counseling. We agree that genetic counseling is important, as is a detailed physical examination for subtle features of genetically mediated aortic aneurysm. In fact, we incorporate the physical examination when patients are seen at our aortic center so as to recognize the physical features. We do routinely recommend screening of first-degree relatives even without significant family history on an individual basis and make appropriate referrals for other conditions that can be seen in these patients. Our article, however, is primarily intended to emphasize the importance of referring these patients for more-focused care at a specialized center, where we incorporate all of the suggestions that were made.

In Reply: We thank Drs. Goldstein and Mascitelli for their comments regarding fluoroquinolones and thoracic aortic aneurysms. We acknowledge that fluoroquinolones (particularly ciprofloxacin) have been associated with a risk of aortic aneurysm and dissection based on large observational studies from Taiwan, Canada, and Sweden. Although all of the studies have shown an association between ciprofloxacin and aortic aneurysm, the causative role is not well established. In addition, the numbers of events were very small in these large cohorts of patients. In our large tertiary care practice at Cleveland Clinic, we have very few patients with aortic aneurysm or dissection who have used fluoroquinolones.

We recognize the association; however, our paper was intended to emphasize the more common causes and treatment options that primary care physicians are likely to encounter in routine practice.

We also thank Drs. Ayoubieh and MacCarrick for their comments about genetic counseling. We agree that genetic counseling is important, as is a detailed physical examination for subtle features of genetically mediated aortic aneurysm. In fact, we incorporate the physical examination when patients are seen at our aortic center so as to recognize the physical features. We do routinely recommend screening of first-degree relatives even without significant family history on an individual basis and make appropriate referrals for other conditions that can be seen in these patients. Our article, however, is primarily intended to emphasize the importance of referring these patients for more-focused care at a specialized center, where we incorporate all of the suggestions that were made.

In Reply: We thank Drs. Goldstein and Mascitelli for their comments regarding fluoroquinolones and thoracic aortic aneurysms. We acknowledge that fluoroquinolones (particularly ciprofloxacin) have been associated with a risk of aortic aneurysm and dissection based on large observational studies from Taiwan, Canada, and Sweden. Although all of the studies have shown an association between ciprofloxacin and aortic aneurysm, the causative role is not well established. In addition, the numbers of events were very small in these large cohorts of patients. In our large tertiary care practice at Cleveland Clinic, we have very few patients with aortic aneurysm or dissection who have used fluoroquinolones.

We recognize the association; however, our paper was intended to emphasize the more common causes and treatment options that primary care physicians are likely to encounter in routine practice.

We also thank Drs. Ayoubieh and MacCarrick for their comments about genetic counseling. We agree that genetic counseling is important, as is a detailed physical examination for subtle features of genetically mediated aortic aneurysm. In fact, we incorporate the physical examination when patients are seen at our aortic center so as to recognize the physical features. We do routinely recommend screening of first-degree relatives even without significant family history on an individual basis and make appropriate referrals for other conditions that can be seen in these patients. Our article, however, is primarily intended to emphasize the importance of referring these patients for more-focused care at a specialized center, where we incorporate all of the suggestions that were made.

CHICAGO—Lowering systolic blood pressure to a target of 120 mm Hg or less in people with cardiovascular risk factors reduces the risk of mild cognitive impairment (MCI) by 19% and reduces the risk of probable all-cause dementia by 17%, compared with achieving a less intensive target of lower than 140 mm Hg, according to research presented at AAIC 2018.

The class of antihypertensive did not affect the association. Generic drugs were as effective as branded drugs. Antihypertensive agents provided equal benefits to men, women, whites, blacks, and Hispanics. Furthermore, maintaining systolic blood pressure at 120 mm Hg or lower prevented MCI as well in patients older than 75 as it did in younger patients.

Jeff D. Williamson, MD, Chief of Geriatric Medicine at Wake Forest University in Winston-Salem, North Carolina, presented the results of the four-year SPRINT MIND study. Strict blood pressure control (ie, a systolic target of 120 mm Hg or lower) for 3.2 years reduced the incidence of MCI to a greater extent than any amyloid-targeting investigational drug has done.

“This is the first disease-modifying strategy to reduce the risk of MCI,” said Dr. Williamson. Although the effect of strict blood pressure control on the primary end point (ie, a 17% risk reduction for probable all-cause dementia) was not statistically significant, “it is comforting to see that the benefit went in the same direction and was of the same magnitude,” said Dr. Williamson. “Three years of treatment and 3.2 years of follow-up absolutely reduced the risk.”

Brain imaging underscored the clinical importance of this finding and showed its physiologic pathway. Participants who underwent strict blood pressure control had 18% fewer white matter hyperintensities after four years of follow-up than other participants.

The results may represent a step forward in a field that has seen few of them recently. Generic antihypertensive agents can be inexpensive. They are widely available and confer benefits not only on cardiovascular health, but on kidney health as well, said Dr. Williamson.

“Hypertension is a highly prevalent condition…. The 19% overall risk reduction for MCI will have a huge impact,” he added.

“The most we can say right now is that we are able to reduce risk,” said Maria Carrillo, PhD, Chief Scientific Officer of the Alzheimer’s Association, in an interview. “Reducing the risk of MCI by 19% will have a huge impact on dementia overall. Slowing down the disease progress is a disease modification, versus developing symptoms. So, if that is the definition we are using, then I would say yes, it is disease modifying,” for dementias arising from cerebrovascular pathology.

A Substudy of the SPRINT Trial

SPRINT MIND was a substudy of the Hypertension Systolic Blood Pressure Intervention Trial (SPRINT). It compared two strategies for managing hypertension in older adults. The intensive strategy had a target systolic blood pressure of less than 120 mm Hg, and the standard care strategy had a target of less than 140 mm Hg. SPRINT showed that intensive blood pressure control reduced the risk of cardiovascular events, stroke, and cardiovascular death by 30%. The study results helped inform the 2017 American Heart Association and American College of Cardiology clinical guidelines for treating high blood pressure.

The SPRINT MIND substudy examined whether intensive blood pressure management affected the risk of probable all-cause dementia or MCI or affected white matter lesion volume and brain volume.

The investigators examined data for 9,361 SPRINT subjects who were age 50 or older (mean age, 68) and had at least one cardiovascular risk factor. Approximately 30% of participants were black, and 10% were Hispanic. The primary outcome was incident probable dementia. Secondary outcomes were MCI and a composite of MCI and probable dementia.

In SPRINT, physicians could choose any appropriate antihypertensive regimen, but were encouraged to use drugs with the strongest evidence of cardiovascular benefit. These drugs included thiazide-type diuretics, loop diuretics, and beta-adrenergic blockers. About 90% of the drugs used during the study were generic.

Subjects were seen monthly for the first three months. During this time, medications were adjusted to achieve the target blood pressure. After the third month, subjects were examined every three months. Medications could be adjusted monthly.

Results Favored Intensive Treatment

At one year, mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard treatment group. Treatment was stopped early after a median follow-up of 3.26 years because of the observed cardiovascular disease benefit.

The SPRINT MIND study did not meet its primary end point. Incident probable all-cause dementia occurred in 175 people in the standard care group and 147 people in the intensive treatment group. The difference between groups in the rate of 17% risk reduction was not statistically significant.

The results for both secondary end points were significant, however. Incident MCI occurred in 348 participants in the standard treatment group and 285 participants in the intensive treatment group. The difference indicated a statistically significant 19% risk reduction associated with intensive treatment. Furthermore, intensive treatment significantly reduced the risk of the combined secondary end point of MCI and probable dementia by 15%. In all, 463 participants in the standard care group met this end point, compared with 398 in the intensive care group.

The imaging study included 454 subjects who had brain MRI at baseline and at four years after randomization. Total brain volume did not change, said Ilya Nasrallah, MD, Assistant Professor of Radiology at the University of Pennsylvania in Philadelphia. Patients in the intensively managed group, however, had 18% lower white matter lesion load than those in the standard care group.

White matter lesions often indicate small-vessel disease, which is associated with vascular dementia and, perhaps, Alzheimer’s disease. Most patients with Alzheimer’s disease have a mixed dementia that includes a vascular component, said Dr. Carrillo.

The Gravity of MCI

SPRINT MIND did not follow subjects for longer than four years or include follow-up for amyloid positivity or Alzheimer’s disease diagnosis. Nevertheless, preventing MCI is a significant achievement, according to David Knopman, MD, a consultant in the department of neurology at Mayo Clinic in Rochester, Minnesota.

“There is nothing benign about MCI,” said Dr. Knopman. “It is the first sign of overt cognitive dysfunction, and although the rate at which MCI progresses to dementia is slow, the appearance of it is just as important as the appearance of more severe dementia. To be able to see an effect in 3.2 years is quite remarkable. I think this study is going to change clinical practice for people in primary care, and the benefits at the population level are going to be substantial.”

Physicians may want to think about how the SPRINT MIND results might apply to younger patients with hypertension, whether they have other cardiovascular risk factors or not, said Dr. Williamson. “I will adhere to the guidelines we have and keep blood pressure at less than 130 mm Hg and certainly start treating people in their 50s, and probably in their 40s,” he concluded.

—Michele G. Sullivan

Suggested Reading

SPRINT Research Group, Wright JT Jr, Williamson JD, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373(22):2103-2116.

CHICAGO—Lowering systolic blood pressure to a target of 120 mm Hg or less in people with cardiovascular risk factors reduces the risk of mild cognitive impairment (MCI) by 19% and reduces the risk of probable all-cause dementia by 17%, compared with achieving a less intensive target of lower than 140 mm Hg, according to research presented at AAIC 2018.

The class of antihypertensive did not affect the association. Generic drugs were as effective as branded drugs. Antihypertensive agents provided equal benefits to men, women, whites, blacks, and Hispanics. Furthermore, maintaining systolic blood pressure at 120 mm Hg or lower prevented MCI as well in patients older than 75 as it did in younger patients.

Jeff D. Williamson, MD, Chief of Geriatric Medicine at Wake Forest University in Winston-Salem, North Carolina, presented the results of the four-year SPRINT MIND study. Strict blood pressure control (ie, a systolic target of 120 mm Hg or lower) for 3.2 years reduced the incidence of MCI to a greater extent than any amyloid-targeting investigational drug has done.

“This is the first disease-modifying strategy to reduce the risk of MCI,” said Dr. Williamson. Although the effect of strict blood pressure control on the primary end point (ie, a 17% risk reduction for probable all-cause dementia) was not statistically significant, “it is comforting to see that the benefit went in the same direction and was of the same magnitude,” said Dr. Williamson. “Three years of treatment and 3.2 years of follow-up absolutely reduced the risk.”

Brain imaging underscored the clinical importance of this finding and showed its physiologic pathway. Participants who underwent strict blood pressure control had 18% fewer white matter hyperintensities after four years of follow-up than other participants.

The results may represent a step forward in a field that has seen few of them recently. Generic antihypertensive agents can be inexpensive. They are widely available and confer benefits not only on cardiovascular health, but on kidney health as well, said Dr. Williamson.

“Hypertension is a highly prevalent condition…. The 19% overall risk reduction for MCI will have a huge impact,” he added.

“The most we can say right now is that we are able to reduce risk,” said Maria Carrillo, PhD, Chief Scientific Officer of the Alzheimer’s Association, in an interview. “Reducing the risk of MCI by 19% will have a huge impact on dementia overall. Slowing down the disease progress is a disease modification, versus developing symptoms. So, if that is the definition we are using, then I would say yes, it is disease modifying,” for dementias arising from cerebrovascular pathology.

A Substudy of the SPRINT Trial

SPRINT MIND was a substudy of the Hypertension Systolic Blood Pressure Intervention Trial (SPRINT). It compared two strategies for managing hypertension in older adults. The intensive strategy had a target systolic blood pressure of less than 120 mm Hg, and the standard care strategy had a target of less than 140 mm Hg. SPRINT showed that intensive blood pressure control reduced the risk of cardiovascular events, stroke, and cardiovascular death by 30%. The study results helped inform the 2017 American Heart Association and American College of Cardiology clinical guidelines for treating high blood pressure.

The SPRINT MIND substudy examined whether intensive blood pressure management affected the risk of probable all-cause dementia or MCI or affected white matter lesion volume and brain volume.

The investigators examined data for 9,361 SPRINT subjects who were age 50 or older (mean age, 68) and had at least one cardiovascular risk factor. Approximately 30% of participants were black, and 10% were Hispanic. The primary outcome was incident probable dementia. Secondary outcomes were MCI and a composite of MCI and probable dementia.

In SPRINT, physicians could choose any appropriate antihypertensive regimen, but were encouraged to use drugs with the strongest evidence of cardiovascular benefit. These drugs included thiazide-type diuretics, loop diuretics, and beta-adrenergic blockers. About 90% of the drugs used during the study were generic.

Subjects were seen monthly for the first three months. During this time, medications were adjusted to achieve the target blood pressure. After the third month, subjects were examined every three months. Medications could be adjusted monthly.

Results Favored Intensive Treatment

At one year, mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard treatment group. Treatment was stopped early after a median follow-up of 3.26 years because of the observed cardiovascular disease benefit.

The SPRINT MIND study did not meet its primary end point. Incident probable all-cause dementia occurred in 175 people in the standard care group and 147 people in the intensive treatment group. The difference between groups in the rate of 17% risk reduction was not statistically significant.

The results for both secondary end points were significant, however. Incident MCI occurred in 348 participants in the standard treatment group and 285 participants in the intensive treatment group. The difference indicated a statistically significant 19% risk reduction associated with intensive treatment. Furthermore, intensive treatment significantly reduced the risk of the combined secondary end point of MCI and probable dementia by 15%. In all, 463 participants in the standard care group met this end point, compared with 398 in the intensive care group.

The imaging study included 454 subjects who had brain MRI at baseline and at four years after randomization. Total brain volume did not change, said Ilya Nasrallah, MD, Assistant Professor of Radiology at the University of Pennsylvania in Philadelphia. Patients in the intensively managed group, however, had 18% lower white matter lesion load than those in the standard care group.

White matter lesions often indicate small-vessel disease, which is associated with vascular dementia and, perhaps, Alzheimer’s disease. Most patients with Alzheimer’s disease have a mixed dementia that includes a vascular component, said Dr. Carrillo.

The Gravity of MCI

SPRINT MIND did not follow subjects for longer than four years or include follow-up for amyloid positivity or Alzheimer’s disease diagnosis. Nevertheless, preventing MCI is a significant achievement, according to David Knopman, MD, a consultant in the department of neurology at Mayo Clinic in Rochester, Minnesota.

“There is nothing benign about MCI,” said Dr. Knopman. “It is the first sign of overt cognitive dysfunction, and although the rate at which MCI progresses to dementia is slow, the appearance of it is just as important as the appearance of more severe dementia. To be able to see an effect in 3.2 years is quite remarkable. I think this study is going to change clinical practice for people in primary care, and the benefits at the population level are going to be substantial.”

Physicians may want to think about how the SPRINT MIND results might apply to younger patients with hypertension, whether they have other cardiovascular risk factors or not, said Dr. Williamson. “I will adhere to the guidelines we have and keep blood pressure at less than 130 mm Hg and certainly start treating people in their 50s, and probably in their 40s,” he concluded.

—Michele G. Sullivan

Suggested Reading

SPRINT Research Group, Wright JT Jr, Williamson JD, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373(22):2103-2116.

CHICAGO—Lowering systolic blood pressure to a target of 120 mm Hg or less in people with cardiovascular risk factors reduces the risk of mild cognitive impairment (MCI) by 19% and reduces the risk of probable all-cause dementia by 17%, compared with achieving a less intensive target of lower than 140 mm Hg, according to research presented at AAIC 2018.

The class of antihypertensive did not affect the association. Generic drugs were as effective as branded drugs. Antihypertensive agents provided equal benefits to men, women, whites, blacks, and Hispanics. Furthermore, maintaining systolic blood pressure at 120 mm Hg or lower prevented MCI as well in patients older than 75 as it did in younger patients.

Jeff D. Williamson, MD, Chief of Geriatric Medicine at Wake Forest University in Winston-Salem, North Carolina, presented the results of the four-year SPRINT MIND study. Strict blood pressure control (ie, a systolic target of 120 mm Hg or lower) for 3.2 years reduced the incidence of MCI to a greater extent than any amyloid-targeting investigational drug has done.

“This is the first disease-modifying strategy to reduce the risk of MCI,” said Dr. Williamson. Although the effect of strict blood pressure control on the primary end point (ie, a 17% risk reduction for probable all-cause dementia) was not statistically significant, “it is comforting to see that the benefit went in the same direction and was of the same magnitude,” said Dr. Williamson. “Three years of treatment and 3.2 years of follow-up absolutely reduced the risk.”

Brain imaging underscored the clinical importance of this finding and showed its physiologic pathway. Participants who underwent strict blood pressure control had 18% fewer white matter hyperintensities after four years of follow-up than other participants.

The results may represent a step forward in a field that has seen few of them recently. Generic antihypertensive agents can be inexpensive. They are widely available and confer benefits not only on cardiovascular health, but on kidney health as well, said Dr. Williamson.

“Hypertension is a highly prevalent condition…. The 19% overall risk reduction for MCI will have a huge impact,” he added.

“The most we can say right now is that we are able to reduce risk,” said Maria Carrillo, PhD, Chief Scientific Officer of the Alzheimer’s Association, in an interview. “Reducing the risk of MCI by 19% will have a huge impact on dementia overall. Slowing down the disease progress is a disease modification, versus developing symptoms. So, if that is the definition we are using, then I would say yes, it is disease modifying,” for dementias arising from cerebrovascular pathology.

A Substudy of the SPRINT Trial

SPRINT MIND was a substudy of the Hypertension Systolic Blood Pressure Intervention Trial (SPRINT). It compared two strategies for managing hypertension in older adults. The intensive strategy had a target systolic blood pressure of less than 120 mm Hg, and the standard care strategy had a target of less than 140 mm Hg. SPRINT showed that intensive blood pressure control reduced the risk of cardiovascular events, stroke, and cardiovascular death by 30%. The study results helped inform the 2017 American Heart Association and American College of Cardiology clinical guidelines for treating high blood pressure.

The SPRINT MIND substudy examined whether intensive blood pressure management affected the risk of probable all-cause dementia or MCI or affected white matter lesion volume and brain volume.

The investigators examined data for 9,361 SPRINT subjects who were age 50 or older (mean age, 68) and had at least one cardiovascular risk factor. Approximately 30% of participants were black, and 10% were Hispanic. The primary outcome was incident probable dementia. Secondary outcomes were MCI and a composite of MCI and probable dementia.

In SPRINT, physicians could choose any appropriate antihypertensive regimen, but were encouraged to use drugs with the strongest evidence of cardiovascular benefit. These drugs included thiazide-type diuretics, loop diuretics, and beta-adrenergic blockers. About 90% of the drugs used during the study were generic.

Subjects were seen monthly for the first three months. During this time, medications were adjusted to achieve the target blood pressure. After the third month, subjects were examined every three months. Medications could be adjusted monthly.

Results Favored Intensive Treatment

At one year, mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard treatment group. Treatment was stopped early after a median follow-up of 3.26 years because of the observed cardiovascular disease benefit.

The SPRINT MIND study did not meet its primary end point. Incident probable all-cause dementia occurred in 175 people in the standard care group and 147 people in the intensive treatment group. The difference between groups in the rate of 17% risk reduction was not statistically significant.

The results for both secondary end points were significant, however. Incident MCI occurred in 348 participants in the standard treatment group and 285 participants in the intensive treatment group. The difference indicated a statistically significant 19% risk reduction associated with intensive treatment. Furthermore, intensive treatment significantly reduced the risk of the combined secondary end point of MCI and probable dementia by 15%. In all, 463 participants in the standard care group met this end point, compared with 398 in the intensive care group.

The imaging study included 454 subjects who had brain MRI at baseline and at four years after randomization. Total brain volume did not change, said Ilya Nasrallah, MD, Assistant Professor of Radiology at the University of Pennsylvania in Philadelphia. Patients in the intensively managed group, however, had 18% lower white matter lesion load than those in the standard care group.

White matter lesions often indicate small-vessel disease, which is associated with vascular dementia and, perhaps, Alzheimer’s disease. Most patients with Alzheimer’s disease have a mixed dementia that includes a vascular component, said Dr. Carrillo.

The Gravity of MCI

SPRINT MIND did not follow subjects for longer than four years or include follow-up for amyloid positivity or Alzheimer’s disease diagnosis. Nevertheless, preventing MCI is a significant achievement, according to David Knopman, MD, a consultant in the department of neurology at Mayo Clinic in Rochester, Minnesota.

“There is nothing benign about MCI,” said Dr. Knopman. “It is the first sign of overt cognitive dysfunction, and although the rate at which MCI progresses to dementia is slow, the appearance of it is just as important as the appearance of more severe dementia. To be able to see an effect in 3.2 years is quite remarkable. I think this study is going to change clinical practice for people in primary care, and the benefits at the population level are going to be substantial.”

Physicians may want to think about how the SPRINT MIND results might apply to younger patients with hypertension, whether they have other cardiovascular risk factors or not, said Dr. Williamson. “I will adhere to the guidelines we have and keep blood pressure at less than 130 mm Hg and certainly start treating people in their 50s, and probably in their 40s,” he concluded.

—Michele G. Sullivan

Suggested Reading

SPRINT Research Group, Wright JT Jr, Williamson JD, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373(22):2103-2116.

Biosimilars are copies of FDA-approved biologic drugs (those generally derived from a living organism) that cannot be identical to the reference drug but demonstrate a high similarity to it. As patents on the reference drugs expire, biosimilars are being developed to increase competition in the marketplace to reduce costs and improve patient access to therapy. Although the US Food and Drug Administration (FDA) has no regulatory power over drug prices, it recently announced efforts to streamline the biosimilar approval process to facilitate access to therapies and curb the associated skyrocketing costs.

Several biosimilars have been approved by the agency in recent years, and earlier this year they were joined by 2 more: the approval in May of epoetin alfa-epbx (Retacrit; Hospira, a Pfizer company) for all indications of the reference product (epoetin alfa; Epogen/Procrit, Amgen), including the treatment of anemia caused by myelosuppressive chemotherapy, when there is a minimum of 2 additional months of planned chemotherapy;¹ and the June approval of pegfilgrastim-jmdb (Fulphila, Mylan and Biocon) for the treatment of patients undergoing myelosuppressive chemotherapy to help reduce the chance of infection as suggested by febrile neutropenia (fever, often with other signs of infection, associated with an abnormally low number of infection-fighting white blood cells).² The reference product for pegfilgrastim-jmdb is pegfilgrastim (Neulasta, Amgen).

The approval of both biosimilars was based on a review of a body of evidence that included structural and functional characterization, animal study data, human pharmacokinetic (PK) and pharmacodynamic (PD) data, clinical immunogenicity data, and other clinical safety and efficacy data. This evidence established that the biosimilars were highly similar to the already FDA-approved reference products, with no clinically relevant differences.



Biocon and Mylan-GmBH, which jointly developed pegfilgrastim-jmdb, originally filed for approval in 2017; and Hospira Inc, a Pfizer company that developed epoetin alfa-epbx, filed for the first time in 2015. They subsequently received complete response letters from the FDA, twice in the case of the epoetin alfa biosimilar, rejecting their approval. For pegfilgrastim-jmdb, the complete response letter was related to a pending update of the Biologic License Application as the result of requalification activities taken because of modifications at their manufacturing plant. For epoetin alfa-epbx, the FDA expressed concerns relating to a manufacturing facility. The companies addressed the concerns in the complete response letters and submitted corrective and preventive action plans.^3,4

Pegfilgrastim-jmdb

The results from a phase 3, multicenter, randomized, double-blind parallel-group trial of pegfilgrastim-jmdb compared with European Union-approved pegfilgrastim were published in 2016. Chemotherapy and radiation-naïve patients with newly diagnosed breast cancer (n = 194) received the biosimilar or reference product every 3 weeks for 6 cycles. The primary endpoint was duration of severe neutropenia in cycle 1, defined as days with absolute neutrophil count <0.5 x 10⁹/L. The mean standard deviation was 1.2 [0.93] in the pegfilgrastim-jmdb arm and 1.2 [1.10] in the EU-pegfilgrastim arm, and the 95% confidence interval of least squares means differences was within the -1 day, +1 day range, indicating equivalency.⁵

A characterization and similarity assessment of pegfilgrastim-jmdb compared with US- and EU-approved pegfilgrastim was presented at the 2018 Annual Meeting of the American Society of Clinical Oncology. G-CSF receptor (G-CSFR) binding was assessed by surface plasmon resonance and potency was measured by in vitro stimulated proliferation in a mouse myelogenous leukemia cell line. In vivo rodent studies were also performed and included a PD study with a single dose of up to 3 mg/kg.⁶

There was high similarity in the structure, molecular mass, impurities and functional activity of the biosimilar and reference products, as well as similar G-CSFR binding and equivalent relative potency. Neutrophil and leukocyte counts were increased to a similar degree, and toxicology and drug kinetics were also comparable.

The recommended dose of pegfilgrastim-jmdb is a 6 mg/0.6 ml injection in a single-dose prefilled syringe for manual use only, administered subcutaneously once per chemotherapy cycle. The prescribing information also has dosing guidelines for administration in pediatric patients who weigh less than 45 kg. Pegfilgrastim-jmdb should not be administered between 14 days before and 24 hours after administration of chemotherapy.

The prescribing information details warnings and precautions relating to splenic rupture, acute respiratory distress syndrome (ARDS), serious allergic reactions, potential for severe/fatal sickle cell crises in patients with sickle cell disorders, glomerulonephritis, leukocytosis, capillary leak syndrome, and the potential for tumor growth or recurrence.⁷

Patients should be evaluated for an enlarged spleen or splenic rupture if they report upper left abdominal or shoulder pain. Patients who develop fever and lung infiltrates or respiratory distress should be evaluated for ARDS and treatment discontinued if a diagnosis is confirmed. Pegfilgrastim-jmdb should be permanently discontinued in patients who develop serious allergic reactions and should not be used in patients with a history of serious allergic reactions to pegfilgrastim or filgrastim products.

Dose-reduction or interruption should be considered in patients who develop glomerulonephritis. Complete blood counts should be monitored throughout treatment. Patients should be monitored closely for capillary leak syndrome and treated with standard therapy. Pegfilgrastim-jmdb is marketed as Fulphila.

Epoetin alfa-epbx

Epoetin alfa-epbx was evaluated in 2 clinical trials in healthy individuals. The EPOE-12-02 trial established the PK and PD following a single subcutaneous dose of 100 U/kg in 81 participants. The EPOE-14-1 study was designed to determine the PK and PD of multiple doses of subcutaneous 100 U/kg 3 times weekly for 3 weeks in 129 participants. Both studies met prespecified criteria for PK and PD similarity to US-approved epoetin alfa, including geometric mean of area under the curve (AUC)0-120h, AUC0-inf, C_max (maximum serum concentration achieved by a drug in a specified area of the body) and E_max (maximum response achievable for a drug dose).

Evidence of efficacy and safety were also evaluated using pooled data from EPOE-10-13 and EPOE-10-01, conducted in patients with chronic kidney disease, which was considered the most sensitive population in which to evaluate clinically meaningful differences between the biosimilar and reference product.^8,9

There were no clinically meaningful differences in efficacy and a similar adverse event profile. The most common side effects include high blood pressure, joint pain, muscle spasm, fever, dizziness, respiratory infection, and cough, among others.

The recommended dose of epoetin alfa-epbx, which is marketed as Retacrit, is 40,000 Units weekly or 150 U/kg 3 times weekly in adults and 600 U/kg intravenously weekly in pediatric patients aged 5 years or younger. Epoetin alfa-epbx comes with a boxed warning to alert health care providers to the increased risks of death, heart problems, stroke, and tumor growth, or recurrence. The prescribing information also details warnings and precautions relating to these risks, as well as hypertension, seizures, lack or loss of hemoglobin response, pure red cell aplasia, serious allergic reactions, and severe cutaneous reactions.⁹

Blood pressure should be appropriately controlled before treatment initiation, treatment should be reduced or withheld if it becomes uncontrollable, and patients should be advised of the importance of compliance with anti-hypertensive medication and dietary restrictions. Patients should be monitored closely for premonitory neurologic symptoms and advised to contact their provider in the event of new-onset seizures, premonitory symptoms, or change in seizure frequency.

The prescribing information has dosing recommendations for lack or loss of hemoglobin response to epoetin alfa-epbx. If severe anemia or low reticulocyte count occur, treatment should be withheld and patients evaluated for neutralizing antibodies to erythropoietin and, in the event that PRCA is confirmed, treatment should be permanently discontinued. Treatment should be immediately and permanently discontinued for serious allergic reactions or severe cutaneous reactions.

Biosimilars are copies of FDA-approved biologic drugs (those generally derived from a living organism) that cannot be identical to the reference drug but demonstrate a high similarity to it. As patents on the reference drugs expire, biosimilars are being developed to increase competition in the marketplace to reduce costs and improve patient access to therapy. Although the US Food and Drug Administration (FDA) has no regulatory power over drug prices, it recently announced efforts to streamline the biosimilar approval process to facilitate access to therapies and curb the associated skyrocketing costs.

Several biosimilars have been approved by the agency in recent years, and earlier this year they were joined by 2 more: the approval in May of epoetin alfa-epbx (Retacrit; Hospira, a Pfizer company) for all indications of the reference product (epoetin alfa; Epogen/Procrit, Amgen), including the treatment of anemia caused by myelosuppressive chemotherapy, when there is a minimum of 2 additional months of planned chemotherapy;¹ and the June approval of pegfilgrastim-jmdb (Fulphila, Mylan and Biocon) for the treatment of patients undergoing myelosuppressive chemotherapy to help reduce the chance of infection as suggested by febrile neutropenia (fever, often with other signs of infection, associated with an abnormally low number of infection-fighting white blood cells).² The reference product for pegfilgrastim-jmdb is pegfilgrastim (Neulasta, Amgen).

The approval of both biosimilars was based on a review of a body of evidence that included structural and functional characterization, animal study data, human pharmacokinetic (PK) and pharmacodynamic (PD) data, clinical immunogenicity data, and other clinical safety and efficacy data. This evidence established that the biosimilars were highly similar to the already FDA-approved reference products, with no clinically relevant differences.



Biocon and Mylan-GmBH, which jointly developed pegfilgrastim-jmdb, originally filed for approval in 2017; and Hospira Inc, a Pfizer company that developed epoetin alfa-epbx, filed for the first time in 2015. They subsequently received complete response letters from the FDA, twice in the case of the epoetin alfa biosimilar, rejecting their approval. For pegfilgrastim-jmdb, the complete response letter was related to a pending update of the Biologic License Application as the result of requalification activities taken because of modifications at their manufacturing plant. For epoetin alfa-epbx, the FDA expressed concerns relating to a manufacturing facility. The companies addressed the concerns in the complete response letters and submitted corrective and preventive action plans.^3,4

Pegfilgrastim-jmdb

The results from a phase 3, multicenter, randomized, double-blind parallel-group trial of pegfilgrastim-jmdb compared with European Union-approved pegfilgrastim were published in 2016. Chemotherapy and radiation-naïve patients with newly diagnosed breast cancer (n = 194) received the biosimilar or reference product every 3 weeks for 6 cycles. The primary endpoint was duration of severe neutropenia in cycle 1, defined as days with absolute neutrophil count <0.5 x 10⁹/L. The mean standard deviation was 1.2 [0.93] in the pegfilgrastim-jmdb arm and 1.2 [1.10] in the EU-pegfilgrastim arm, and the 95% confidence interval of least squares means differences was within the -1 day, +1 day range, indicating equivalency.⁵

A characterization and similarity assessment of pegfilgrastim-jmdb compared with US- and EU-approved pegfilgrastim was presented at the 2018 Annual Meeting of the American Society of Clinical Oncology. G-CSF receptor (G-CSFR) binding was assessed by surface plasmon resonance and potency was measured by in vitro stimulated proliferation in a mouse myelogenous leukemia cell line. In vivo rodent studies were also performed and included a PD study with a single dose of up to 3 mg/kg.⁶

There was high similarity in the structure, molecular mass, impurities and functional activity of the biosimilar and reference products, as well as similar G-CSFR binding and equivalent relative potency. Neutrophil and leukocyte counts were increased to a similar degree, and toxicology and drug kinetics were also comparable.

The recommended dose of pegfilgrastim-jmdb is a 6 mg/0.6 ml injection in a single-dose prefilled syringe for manual use only, administered subcutaneously once per chemotherapy cycle. The prescribing information also has dosing guidelines for administration in pediatric patients who weigh less than 45 kg. Pegfilgrastim-jmdb should not be administered between 14 days before and 24 hours after administration of chemotherapy.

The prescribing information details warnings and precautions relating to splenic rupture, acute respiratory distress syndrome (ARDS), serious allergic reactions, potential for severe/fatal sickle cell crises in patients with sickle cell disorders, glomerulonephritis, leukocytosis, capillary leak syndrome, and the potential for tumor growth or recurrence.⁷

Patients should be evaluated for an enlarged spleen or splenic rupture if they report upper left abdominal or shoulder pain. Patients who develop fever and lung infiltrates or respiratory distress should be evaluated for ARDS and treatment discontinued if a diagnosis is confirmed. Pegfilgrastim-jmdb should be permanently discontinued in patients who develop serious allergic reactions and should not be used in patients with a history of serious allergic reactions to pegfilgrastim or filgrastim products.

Dose-reduction or interruption should be considered in patients who develop glomerulonephritis. Complete blood counts should be monitored throughout treatment. Patients should be monitored closely for capillary leak syndrome and treated with standard therapy. Pegfilgrastim-jmdb is marketed as Fulphila.

Epoetin alfa-epbx

Epoetin alfa-epbx was evaluated in 2 clinical trials in healthy individuals. The EPOE-12-02 trial established the PK and PD following a single subcutaneous dose of 100 U/kg in 81 participants. The EPOE-14-1 study was designed to determine the PK and PD of multiple doses of subcutaneous 100 U/kg 3 times weekly for 3 weeks in 129 participants. Both studies met prespecified criteria for PK and PD similarity to US-approved epoetin alfa, including geometric mean of area under the curve (AUC)0-120h, AUC0-inf, C_max (maximum serum concentration achieved by a drug in a specified area of the body) and E_max (maximum response achievable for a drug dose).

Evidence of efficacy and safety were also evaluated using pooled data from EPOE-10-13 and EPOE-10-01, conducted in patients with chronic kidney disease, which was considered the most sensitive population in which to evaluate clinically meaningful differences between the biosimilar and reference product.^8,9

There were no clinically meaningful differences in efficacy and a similar adverse event profile. The most common side effects include high blood pressure, joint pain, muscle spasm, fever, dizziness, respiratory infection, and cough, among others.

The recommended dose of epoetin alfa-epbx, which is marketed as Retacrit, is 40,000 Units weekly or 150 U/kg 3 times weekly in adults and 600 U/kg intravenously weekly in pediatric patients aged 5 years or younger. Epoetin alfa-epbx comes with a boxed warning to alert health care providers to the increased risks of death, heart problems, stroke, and tumor growth, or recurrence. The prescribing information also details warnings and precautions relating to these risks, as well as hypertension, seizures, lack or loss of hemoglobin response, pure red cell aplasia, serious allergic reactions, and severe cutaneous reactions.⁹

Blood pressure should be appropriately controlled before treatment initiation, treatment should be reduced or withheld if it becomes uncontrollable, and patients should be advised of the importance of compliance with anti-hypertensive medication and dietary restrictions. Patients should be monitored closely for premonitory neurologic symptoms and advised to contact their provider in the event of new-onset seizures, premonitory symptoms, or change in seizure frequency.

The prescribing information has dosing recommendations for lack or loss of hemoglobin response to epoetin alfa-epbx. If severe anemia or low reticulocyte count occur, treatment should be withheld and patients evaluated for neutralizing antibodies to erythropoietin and, in the event that PRCA is confirmed, treatment should be permanently discontinued. Treatment should be immediately and permanently discontinued for serious allergic reactions or severe cutaneous reactions.

Biosimilars are copies of FDA-approved biologic drugs (those generally derived from a living organism) that cannot be identical to the reference drug but demonstrate a high similarity to it. As patents on the reference drugs expire, biosimilars are being developed to increase competition in the marketplace to reduce costs and improve patient access to therapy. Although the US Food and Drug Administration (FDA) has no regulatory power over drug prices, it recently announced efforts to streamline the biosimilar approval process to facilitate access to therapies and curb the associated skyrocketing costs.

Several biosimilars have been approved by the agency in recent years, and earlier this year they were joined by 2 more: the approval in May of epoetin alfa-epbx (Retacrit; Hospira, a Pfizer company) for all indications of the reference product (epoetin alfa; Epogen/Procrit, Amgen), including the treatment of anemia caused by myelosuppressive chemotherapy, when there is a minimum of 2 additional months of planned chemotherapy;¹ and the June approval of pegfilgrastim-jmdb (Fulphila, Mylan and Biocon) for the treatment of patients undergoing myelosuppressive chemotherapy to help reduce the chance of infection as suggested by febrile neutropenia (fever, often with other signs of infection, associated with an abnormally low number of infection-fighting white blood cells).² The reference product for pegfilgrastim-jmdb is pegfilgrastim (Neulasta, Amgen).

The approval of both biosimilars was based on a review of a body of evidence that included structural and functional characterization, animal study data, human pharmacokinetic (PK) and pharmacodynamic (PD) data, clinical immunogenicity data, and other clinical safety and efficacy data. This evidence established that the biosimilars were highly similar to the already FDA-approved reference products, with no clinically relevant differences.



Biocon and Mylan-GmBH, which jointly developed pegfilgrastim-jmdb, originally filed for approval in 2017; and Hospira Inc, a Pfizer company that developed epoetin alfa-epbx, filed for the first time in 2015. They subsequently received complete response letters from the FDA, twice in the case of the epoetin alfa biosimilar, rejecting their approval. For pegfilgrastim-jmdb, the complete response letter was related to a pending update of the Biologic License Application as the result of requalification activities taken because of modifications at their manufacturing plant. For epoetin alfa-epbx, the FDA expressed concerns relating to a manufacturing facility. The companies addressed the concerns in the complete response letters and submitted corrective and preventive action plans.^3,4

Pegfilgrastim-jmdb

The results from a phase 3, multicenter, randomized, double-blind parallel-group trial of pegfilgrastim-jmdb compared with European Union-approved pegfilgrastim were published in 2016. Chemotherapy and radiation-naïve patients with newly diagnosed breast cancer (n = 194) received the biosimilar or reference product every 3 weeks for 6 cycles. The primary endpoint was duration of severe neutropenia in cycle 1, defined as days with absolute neutrophil count <0.5 x 10⁹/L. The mean standard deviation was 1.2 [0.93] in the pegfilgrastim-jmdb arm and 1.2 [1.10] in the EU-pegfilgrastim arm, and the 95% confidence interval of least squares means differences was within the -1 day, +1 day range, indicating equivalency.⁵

A characterization and similarity assessment of pegfilgrastim-jmdb compared with US- and EU-approved pegfilgrastim was presented at the 2018 Annual Meeting of the American Society of Clinical Oncology. G-CSF receptor (G-CSFR) binding was assessed by surface plasmon resonance and potency was measured by in vitro stimulated proliferation in a mouse myelogenous leukemia cell line. In vivo rodent studies were also performed and included a PD study with a single dose of up to 3 mg/kg.⁶

There was high similarity in the structure, molecular mass, impurities and functional activity of the biosimilar and reference products, as well as similar G-CSFR binding and equivalent relative potency. Neutrophil and leukocyte counts were increased to a similar degree, and toxicology and drug kinetics were also comparable.

The recommended dose of pegfilgrastim-jmdb is a 6 mg/0.6 ml injection in a single-dose prefilled syringe for manual use only, administered subcutaneously once per chemotherapy cycle. The prescribing information also has dosing guidelines for administration in pediatric patients who weigh less than 45 kg. Pegfilgrastim-jmdb should not be administered between 14 days before and 24 hours after administration of chemotherapy.

The prescribing information details warnings and precautions relating to splenic rupture, acute respiratory distress syndrome (ARDS), serious allergic reactions, potential for severe/fatal sickle cell crises in patients with sickle cell disorders, glomerulonephritis, leukocytosis, capillary leak syndrome, and the potential for tumor growth or recurrence.⁷

Patients should be evaluated for an enlarged spleen or splenic rupture if they report upper left abdominal or shoulder pain. Patients who develop fever and lung infiltrates or respiratory distress should be evaluated for ARDS and treatment discontinued if a diagnosis is confirmed. Pegfilgrastim-jmdb should be permanently discontinued in patients who develop serious allergic reactions and should not be used in patients with a history of serious allergic reactions to pegfilgrastim or filgrastim products.

Dose-reduction or interruption should be considered in patients who develop glomerulonephritis. Complete blood counts should be monitored throughout treatment. Patients should be monitored closely for capillary leak syndrome and treated with standard therapy. Pegfilgrastim-jmdb is marketed as Fulphila.

Epoetin alfa-epbx

Epoetin alfa-epbx was evaluated in 2 clinical trials in healthy individuals. The EPOE-12-02 trial established the PK and PD following a single subcutaneous dose of 100 U/kg in 81 participants. The EPOE-14-1 study was designed to determine the PK and PD of multiple doses of subcutaneous 100 U/kg 3 times weekly for 3 weeks in 129 participants. Both studies met prespecified criteria for PK and PD similarity to US-approved epoetin alfa, including geometric mean of area under the curve (AUC)0-120h, AUC0-inf, C_max (maximum serum concentration achieved by a drug in a specified area of the body) and E_max (maximum response achievable for a drug dose).

Evidence of efficacy and safety were also evaluated using pooled data from EPOE-10-13 and EPOE-10-01, conducted in patients with chronic kidney disease, which was considered the most sensitive population in which to evaluate clinically meaningful differences between the biosimilar and reference product.^8,9

There were no clinically meaningful differences in efficacy and a similar adverse event profile. The most common side effects include high blood pressure, joint pain, muscle spasm, fever, dizziness, respiratory infection, and cough, among others.

The recommended dose of epoetin alfa-epbx, which is marketed as Retacrit, is 40,000 Units weekly or 150 U/kg 3 times weekly in adults and 600 U/kg intravenously weekly in pediatric patients aged 5 years or younger. Epoetin alfa-epbx comes with a boxed warning to alert health care providers to the increased risks of death, heart problems, stroke, and tumor growth, or recurrence. The prescribing information also details warnings and precautions relating to these risks, as well as hypertension, seizures, lack or loss of hemoglobin response, pure red cell aplasia, serious allergic reactions, and severe cutaneous reactions.⁹

Blood pressure should be appropriately controlled before treatment initiation, treatment should be reduced or withheld if it becomes uncontrollable, and patients should be advised of the importance of compliance with anti-hypertensive medication and dietary restrictions. Patients should be monitored closely for premonitory neurologic symptoms and advised to contact their provider in the event of new-onset seizures, premonitory symptoms, or change in seizure frequency.

The prescribing information has dosing recommendations for lack or loss of hemoglobin response to epoetin alfa-epbx. If severe anemia or low reticulocyte count occur, treatment should be withheld and patients evaluated for neutralizing antibodies to erythropoietin and, in the event that PRCA is confirmed, treatment should be permanently discontinued. Treatment should be immediately and permanently discontinued for serious allergic reactions or severe cutaneous reactions.

An estimated 72,000 drug overdose deaths occurred in 2017 in the United States, making it the worst year on record, according to preliminary data released by the Centers for Disease Control and Prevention.

The record high was driven by a sharp increase in deaths attributed to synthetic opioids, such as fentanyl and tramadol, data published on the agency’s website show.

The provisional counts are based on death records sent to the CDC’s National Center for Health Statistics from state vital registration offices in all 50 states and the District of Columbia, reported lead author Farida B. Ahmad, MPH, of the division of vital statistics at the NCHS. Overall, the predicted number of drug overdose deaths has climbed steadily, from 54,207 in November 2015 to 66,012 in November 2016, and to 72,287 in November 2017, according to an interactive chart accessible on the website.

Deaths attributable to synthetic opioids have climbed faster than any other drug class, soaring from just 9,983 in 2015 to 20,310 in 2016, and to 29,418 in 2017.

The next-largest category, heroin-related deaths, increased from 13,407 in 2015 to 16,012 in 2016, but appeared to plateau at 15,959 in 2017. However, the CDC cautioned that flat or declining numbers could be attributable to incomplete data, true decreases in deaths, or some combination of the two. “True declines or plateaus in the numbers of drug overdose deaths across the U.S. cannot be ascertained until final data become available.”

Cocaine-related deaths were fewer in number but appear to have risen substantially to the point where the number of deaths now nearly rival that of heroin. The number of deaths was 7,106 in 2015, 10,868 in 2016, and 14,614 in 2017.

The count of drug overdose deaths varied by state. Nebraska had the sharpest increase in predicted deaths between January 2017 and January 2018, coming in at 33.3%, though the absolute numbers of cases were low (114 through January 2017 and 152 through January 2018). North Carolina also showed substantial increases (from 2,053 to 2,515 cases, 22.5%), as did New Jersey (2,219 to 2,687 cases, 21.1%), the CDC data showed.

Provisional data will be updated on a monthly basis as additional records are received, the CDC said.

An estimated 72,000 drug overdose deaths occurred in 2017 in the United States, making it the worst year on record, according to preliminary data released by the Centers for Disease Control and Prevention.

The record high was driven by a sharp increase in deaths attributed to synthetic opioids, such as fentanyl and tramadol, data published on the agency’s website show.

The provisional counts are based on death records sent to the CDC’s National Center for Health Statistics from state vital registration offices in all 50 states and the District of Columbia, reported lead author Farida B. Ahmad, MPH, of the division of vital statistics at the NCHS. Overall, the predicted number of drug overdose deaths has climbed steadily, from 54,207 in November 2015 to 66,012 in November 2016, and to 72,287 in November 2017, according to an interactive chart accessible on the website.

Deaths attributable to synthetic opioids have climbed faster than any other drug class, soaring from just 9,983 in 2015 to 20,310 in 2016, and to 29,418 in 2017.

The next-largest category, heroin-related deaths, increased from 13,407 in 2015 to 16,012 in 2016, but appeared to plateau at 15,959 in 2017. However, the CDC cautioned that flat or declining numbers could be attributable to incomplete data, true decreases in deaths, or some combination of the two. “True declines or plateaus in the numbers of drug overdose deaths across the U.S. cannot be ascertained until final data become available.”

Cocaine-related deaths were fewer in number but appear to have risen substantially to the point where the number of deaths now nearly rival that of heroin. The number of deaths was 7,106 in 2015, 10,868 in 2016, and 14,614 in 2017.

The count of drug overdose deaths varied by state. Nebraska had the sharpest increase in predicted deaths between January 2017 and January 2018, coming in at 33.3%, though the absolute numbers of cases were low (114 through January 2017 and 152 through January 2018). North Carolina also showed substantial increases (from 2,053 to 2,515 cases, 22.5%), as did New Jersey (2,219 to 2,687 cases, 21.1%), the CDC data showed.

Provisional data will be updated on a monthly basis as additional records are received, the CDC said.

An estimated 72,000 drug overdose deaths occurred in 2017 in the United States, making it the worst year on record, according to preliminary data released by the Centers for Disease Control and Prevention.

The record high was driven by a sharp increase in deaths attributed to synthetic opioids, such as fentanyl and tramadol, data published on the agency’s website show.

The provisional counts are based on death records sent to the CDC’s National Center for Health Statistics from state vital registration offices in all 50 states and the District of Columbia, reported lead author Farida B. Ahmad, MPH, of the division of vital statistics at the NCHS. Overall, the predicted number of drug overdose deaths has climbed steadily, from 54,207 in November 2015 to 66,012 in November 2016, and to 72,287 in November 2017, according to an interactive chart accessible on the website.

Deaths attributable to synthetic opioids have climbed faster than any other drug class, soaring from just 9,983 in 2015 to 20,310 in 2016, and to 29,418 in 2017.

The next-largest category, heroin-related deaths, increased from 13,407 in 2015 to 16,012 in 2016, but appeared to plateau at 15,959 in 2017. However, the CDC cautioned that flat or declining numbers could be attributable to incomplete data, true decreases in deaths, or some combination of the two. “True declines or plateaus in the numbers of drug overdose deaths across the U.S. cannot be ascertained until final data become available.”

Cocaine-related deaths were fewer in number but appear to have risen substantially to the point where the number of deaths now nearly rival that of heroin. The number of deaths was 7,106 in 2015, 10,868 in 2016, and 14,614 in 2017.

The count of drug overdose deaths varied by state. Nebraska had the sharpest increase in predicted deaths between January 2017 and January 2018, coming in at 33.3%, though the absolute numbers of cases were low (114 through January 2017 and 152 through January 2018). North Carolina also showed substantial increases (from 2,053 to 2,515 cases, 22.5%), as did New Jersey (2,219 to 2,687 cases, 21.1%), the CDC data showed.

Provisional data will be updated on a monthly basis as additional records are received, the CDC said.

The prevalence of opioid use disorder more than quadrupled among pregnant women at labor and delivery from 1999 to 2014, according to the Centers for Disease Control and Prevention.

The national prevalence of opioid use disorder increased by 333% as it went from 1.5 cases per 1,000 delivery hospitalizations in 1999 to 6.5 cases per 1,000 in 2014. At the state level, there were significant increases in all 28 states with data available for at least 3 consecutive years during the study period, Sarah C. Haight, MPH, and her associates at the CDC in Atlanta said in the Morbidity and Mortality Weekly Report.

Average annual rate changes for those states ranged from a low of 0.01 per 1,000 delivery hospitalizations per year in California to 5.37 per year in Vermont, with the national rate change coming in at 0.39 per year. Of the 14 states with data available in 1999, Iowa had the lowest rate at 0.1 per 1,000 deliveries and Maryland had the highest at 8.2. In 2014, when data were available for 26 states and the District of Columbia, the highest rate was Vermont’s 48.6 per 1,000 deliveries and the lowest was 0.7 in Washington, D.C., the investigators reported.

Although “increasing trends might represent actual increases in prevalence or improved screening and diagnosis,” Ms. Haight and her associates added that “these estimates also correlate with state opioid prescribing rates in the general population. West Virginia, for example, had a prescribing rate estimated at 138 opioid prescriptions per 100 persons in 2012.”

“These findings illustrate the devastating impact of the opioid epidemic on families across the U.S., including on the very youngest,” said CDC Director Robert R. Redfield, MD. “Untreated opioid use disorder during pregnancy can lead to heartbreaking results. Each case represents a mother, a child, and a family in need of continued treatment and support.”

Data for the analysis came from the Agency for Healthcare Research and Quality’s National Inpatient Sample and State Inpatient Databases.

[email protected]

SOURCE: Haight SC et al. MMWR. 2018 Aug 10;67[31]:845-9.

The prevalence of opioid use disorder more than quadrupled among pregnant women at labor and delivery from 1999 to 2014, according to the Centers for Disease Control and Prevention.

The national prevalence of opioid use disorder increased by 333% as it went from 1.5 cases per 1,000 delivery hospitalizations in 1999 to 6.5 cases per 1,000 in 2014. At the state level, there were significant increases in all 28 states with data available for at least 3 consecutive years during the study period, Sarah C. Haight, MPH, and her associates at the CDC in Atlanta said in the Morbidity and Mortality Weekly Report.

Average annual rate changes for those states ranged from a low of 0.01 per 1,000 delivery hospitalizations per year in California to 5.37 per year in Vermont, with the national rate change coming in at 0.39 per year. Of the 14 states with data available in 1999, Iowa had the lowest rate at 0.1 per 1,000 deliveries and Maryland had the highest at 8.2. In 2014, when data were available for 26 states and the District of Columbia, the highest rate was Vermont’s 48.6 per 1,000 deliveries and the lowest was 0.7 in Washington, D.C., the investigators reported.

Although “increasing trends might represent actual increases in prevalence or improved screening and diagnosis,” Ms. Haight and her associates added that “these estimates also correlate with state opioid prescribing rates in the general population. West Virginia, for example, had a prescribing rate estimated at 138 opioid prescriptions per 100 persons in 2012.”

“These findings illustrate the devastating impact of the opioid epidemic on families across the U.S., including on the very youngest,” said CDC Director Robert R. Redfield, MD. “Untreated opioid use disorder during pregnancy can lead to heartbreaking results. Each case represents a mother, a child, and a family in need of continued treatment and support.”

Data for the analysis came from the Agency for Healthcare Research and Quality’s National Inpatient Sample and State Inpatient Databases.

[email protected]

SOURCE: Haight SC et al. MMWR. 2018 Aug 10;67[31]:845-9.

The prevalence of opioid use disorder more than quadrupled among pregnant women at labor and delivery from 1999 to 2014, according to the Centers for Disease Control and Prevention.

The national prevalence of opioid use disorder increased by 333% as it went from 1.5 cases per 1,000 delivery hospitalizations in 1999 to 6.5 cases per 1,000 in 2014. At the state level, there were significant increases in all 28 states with data available for at least 3 consecutive years during the study period, Sarah C. Haight, MPH, and her associates at the CDC in Atlanta said in the Morbidity and Mortality Weekly Report.

Average annual rate changes for those states ranged from a low of 0.01 per 1,000 delivery hospitalizations per year in California to 5.37 per year in Vermont, with the national rate change coming in at 0.39 per year. Of the 14 states with data available in 1999, Iowa had the lowest rate at 0.1 per 1,000 deliveries and Maryland had the highest at 8.2. In 2014, when data were available for 26 states and the District of Columbia, the highest rate was Vermont’s 48.6 per 1,000 deliveries and the lowest was 0.7 in Washington, D.C., the investigators reported.

Although “increasing trends might represent actual increases in prevalence or improved screening and diagnosis,” Ms. Haight and her associates added that “these estimates also correlate with state opioid prescribing rates in the general population. West Virginia, for example, had a prescribing rate estimated at 138 opioid prescriptions per 100 persons in 2012.”

“These findings illustrate the devastating impact of the opioid epidemic on families across the U.S., including on the very youngest,” said CDC Director Robert R. Redfield, MD. “Untreated opioid use disorder during pregnancy can lead to heartbreaking results. Each case represents a mother, a child, and a family in need of continued treatment and support.”

Data for the analysis came from the Agency for Healthcare Research and Quality’s National Inpatient Sample and State Inpatient Databases.

[email protected]

SOURCE: Haight SC et al. MMWR. 2018 Aug 10;67[31]:845-9.

The balance between dietary intake and excretion of phosphorus can be impaired in patients with decreased renal function, leading to hyperphosphatemia. Many patients with end-stage renal disease on dialysis require phosphorus-binding drugs to control their serum phosphorus levels.

See related editorial and article

In this review, we discuss the pathophysiology of hyperphosphatemia in kidney disease, its consequences, and how to control it, focusing on the different classes of phosphorus binders.

ROLE OF THE INTERNIST

With kidney disease common and on the increase,¹ nephrologists and internists need to work together to provide optimal care.

Further, many internists in managed care plans and accountable care organizations now handle many tasks previously left to specialists—including prescribing and managing phosphorus binders in patients with kidney disease.

PATHOPHYSIOLOGY OF HYPERPHOSPHATEMIA

The pathophysiology of bone mineral disorders in kidney disease is complex. To simplify the discussion, we will address it in 3 parts:

• Phosphorus balance
• The interplay of hormones, including fibro­blast growth factor 23 (FGF23)
• The mechanism of hyperphosphatemia in kidney disease.

Phosphorus balance

Phosphorus is a macronutrient essential for a range of cellular functions that include structure, energy production, metabolism, and cell signaling. It exists primarily in the form of inorganic phosphate.

An average Western diet provides 20 mg of phosphorus per kilogram of body weight per day. Of this, 13 mg/kg is absorbed, and the rest is excreted in the feces.²

Absorption of dietary phosphorus occurs mainly in the jejunum. It is mediated by both a paracellular sodium-independent pathway (driven by high intraluminal phosphorus content) and by active sodium-dependent cotransporters. It is also influenced by diet and promoted by active vitamin D (1,25 dihydroxyvitamin D₃, also called calcitriol).³

Absorbed phosphorus enters the extracellular fluid and shifts in and out of the skeleton under the influence of parathyroid hormone.

Phosphorus excretion is handled almost entirely by the kidneys. Phosphorus is freely filtered at the glomerulus and reabsorbed mainly in the proximal tubule by sodium-phosphate cotransporters.

Normally, when phosphorus intake is adequate, most of the filtered phosphorus is reabsorbed and only 10% to 20% is excreted in the urine. However, the threshold for phosphorus reabsorption in the proximal tubule is influenced by parathyroid hormone, FGF23, and dietary phosphorus intake: low serum phosphate levels lead to an increase in the synthesis of sodium-phosphorus cotransporters, resulting in increased (nearly complete) proximal reabsorption and an increase in the serum phosphorus concentration.⁴ Conversely, both parathyroid hormone and FGF23 are phosphaturic and decrease the number of phosphorus transporters, which in turn leads to increased phosphorus excretion and a decrease in serum phosphorus concentration.⁵

Interplay of hormones

FGF23 is a phosphaturic glycoprotein secreted by osteoblasts and osteocytes. It acts by binding to fibroblastic growth receptor 1 in the presence of its coreceptor, the Klotho protein.⁶

FGF23 is regulated by serum phosphorus levels and plays a major role in the response to elevated serum phosphorus. It causes a direct increase in urinary phosphorus excretion, a decrease in intestinal phosphorus absorption (indirectly via inhibition of calcitriol), and decreased bone resorption via a decrease in parathyroid hormone production.⁷

Mechanism of hyperphosphatemia in kidney disease

In chronic kidney disease, phosphorus retention can trigger secondary hyperparathyroidism, as rising phosphorus levels stimulate FGF23. In the early stages of chronic kidney disease, this response can correct the phosphorus levels, but with several consequences:

• Decreased calcitriol due to its inhibition by FGF23⁹
• Hypocalcemia due to decreased calcitriol (leading to decreased intestinal calcium absorption) and calcium binding of retained phosphorus
• Elevated parathyroid hormone due to low calcitriol levels (lack of inhibitory feedback by calcitriol), hyperphosphatemia, and hypocalcemia (direct parathyroid hormone stimulation).

As the elevated phosphorus level is likely to be the triggering event behind secondary renal hyperparathyroidism, it needs to be controlled. This is accomplished by restricting dietary phosphorus and using phosphorus binders.

HYPERPHOSPHATEMIA MAY LEAD TO VASCULAR CALCIFICATION

Elevated serum phosphorus levels (normal range 2.48–4.65 mg/dL in adults¹¹) are associated with cardiovascular calcification and subsequent increases in mortality and morbidity rates. Elevations in serum phosphorus and calcium levels are associated with progression in vascular calcification¹² and likely account for the accelerated vascular calcification that is seen in kidney disease.¹³

Hyperphosphatemia has been identified as an independent risk factor for death in patients with end-stage renal disease,¹⁴ but that relationship is less clear in patients with chronic kidney disease. A study in patients with chronic kidney disease and not on dialysis found a lower mortality rate in those who were prescribed phosphorus binders,¹⁵ but the study was criticized for limitations in its design.

Hyperphosphatemia can also lead to adverse effects on bone health due to complications such as renal osteodystrophy.

However, in its 2017 update, the Kidney Disease: Improving Global Outcomes (KDIGO) program only “suggests” lowering elevated phosphorus levels “toward” the normal range in patients with chronic kidney disease stages G3a through G5D, ie, those with glomerular filtration rates less than 60 mL/min/1.73 m², including those on dialysis. The recommendation is graded 2C, ie, weak, based on low-quality evidence (https://kdigo.org/guidelines/ckd-mbd).

DIETARY RESTRICTION OF PHOSPHORUS

Diet is the major source of phosphorus intake. The average daily phosphorus consumption is  20 mg/kg, or 1,400 mg, and protein is the major source of dietary phosphorus.

In patients with stage 4 or 5 chronic kidney disease, the Kidney Disease Outcomes Quality Initiative recommends limiting protein intake to 0.6 mg/kg/day.¹⁶ However, in patients on hemodialysis, they recommend increasing protein intake to 1.1 mg/kg/day while limiting phosphorus intake to about 800 to 1,000 mg/day. This poses a challenge, as limiting phosphorus intake can reduce protein intake.

Sources of protein can be broadly classified as plant-based or animal-based. Animal protein contains organic phosphorus, which is easily absorbed.¹⁸ Plant protein may not be absorbed as easily.

Moe et al¹⁹ studied the importance of the protein source of phosphorus after 7 days of controlled diets. Despite equivalent protein and phosphorus concentrations in the vegetarian and meat-based diets, participants on the vegetarian diet had lower serum phosphorus levels, a trend toward lower 24-hour urinary phosphorus excretion, and significantly lower FGF23 levels than those on the meat-based diet. This suggests that a vegetarian diet may have advantages in terms of preventing hyperphosphatemia.

Another measure to reduce phosphorus absorption from meat is to boil it, which reduces the phosphorus content by 50%.²⁰

Processed foods containing additives and preservatives are very high in phosphorus²¹ and should be avoided, particularly as there is no mandate to label phosphorus content in food.

PHOSPHORUS AND DIALYSIS

Although hemodialysis removes phosphorus, it does not remove enough to keep levels within normal limits. Indeed, even when patients adhere to a daily phosphorus limit of 1,000 mg, phosphorus accumulates. If 70% of the phosphorus in the diet is absorbed, this is 4,500 to 5,000 mg in a week. A 4-hour hemodialysis session will remove only 1,000 mg of phosphorus, which equals about 3,000 mg for patients undergoing dialysis 3 times a week,²² far less than phosphorus absorption.

In patients on continuous ambulatory peritoneal dialysis, a daily regimen of 4 exchanges of 2 L per exchange removes about 200 mg of phosphorus per day. In a 2012 study, patients on nocturnal dialysis or home dialysis involving longer session length had greater lowering of phosphorus levels than patients undergoing routine hemodialysis.²³

Hence, phosphorus binders are often necessary in patients on routine hemodialysis or peritoneal dialysis.

PHOSPHORUS BINDERS

Phosphorus binders reduce serum phosphorus levels by binding with ingested phosphorus in the gastrointestinal tract and forming insoluble complexes that are not absorbed. For this reason they are much more effective when taken with meals. Phosphorus binders come in different formulations: pills, capsules, chewable tablets, liquids, and even powders that can be sprinkled on food.

The potency of each binder is quantified by its “phosphorus binder equivalent dose,” ie, its binding capacity compared with that of calcium carbonate as a reference.²⁴

Phosphorus binders are broadly divided into those that contain calcium and those that do not.

Calcium-containing binders

The 2 most commonly used preparations are calcium carbonate (eg, Tums) and calcium acetate (eg, Phoslo). While these are relatively safe, some studies suggest that their use can lead to accelerated vascular calcification.²⁵

According to KDIGO,²⁶ calcium-containing binders should be avoided in hypercalcemia and adynamic bone disease. Additionally, the daily elemental calcium intake from binders should be limited to 1,500 mg, with a total daily intake that does not exceed 2,000 mg.

The elemental calcium content of calcium carbonate is about 40% of its weight (eg, 200 mg of elemental calcium in a 500-mg tablet of Tums), while the elemental calcium content of calcium acetate is about 25%. Therefore, a patient who needs 6 g of calcium carbonate for efficacy will be ingesting 2.4 g of elemental calcium per day, and that exceeds the recommended daily maximum. The main advantage of calcium carbonate is its low cost and easy availability. Commonly reported side effects include nausea and constipation.

A less commonly used calcium-based binder is calcium citrate (eg, Calcitrate). It should, however, be avoided in chronic kidney disease because of the risk of aluminum accumulation. Calcium citrate can enhance intestinal absorption of aluminum from dietary sources, as aluminum can form complexes with citrate.²⁷

Calcium-free binders

There are several calcium-free binders. Some are based on metals such as aluminum, magnesium, iron, and lanthanum; others, such as sevelamer, are resin-based.

Aluminum- and magnesium-based binders are generally not used long-term in kidney disease because of the toxicity associated with aluminum and magnesium accumulation. However, aluminum hydroxide has an off-label use as a phosphorus binder in the acute setting, particularly when serum phosphorus levels are above 7 mg/dL.²⁸ The dose is 300 to 600 mg 3 times daily with meals for a maximum of 4 weeks.

Sevelamer. Approved by the US Food and Drug Administration (FDA) in 1998, sevelamer acts by trapping phosphorus through ion exchange and hydrogen binding. It has the advantage of being calcium-free, which makes it particularly desirable in patients with hypercalcemia.

The Renagel in New Dialysis²⁵ and Treat-To-Goal²⁹ studies were randomized controlled trials that looked at the effects of sevelamer vs calcium-based binders on the risk of vascular calcification. The primary end points were serum phosphorus and calcium levels, while the secondary end points were coronary artery calcification on computed tomography and thoracic vertebral bone density. Both studies demonstrated a higher risk of vascular calcification with the calcium-based binders.

Another possible benefit of sevelamer is an improvement in lipid profile. Sevelamer lowers total cholesterol and low-density lipoprotein cholesterol levels without affecting high-density lipoprotein cholesterol or triglyceride levels.³⁰ This is likely due to its bile acid-binding effect.³¹ Sevelamer has also been shown to lower C-reactive protein levels.³² While the cardiovascular profile appears to be improved with the treatment, there are no convincing data to confirm that those properties translate to a proven independent survival benefit.

The Calcium Acetate Renagel Evaluation³³ was a randomized controlled study comparing sevelamer and calcium acetate. The authors attempted to control for the lipid-lowering effects of sevelamer by giving atorvastatin to all patients in both groups who had a low-density lipoprotein level greater than 70 mg/dL. The study found sevelamer to be not inferior to calcium acetate in terms of mortality and coronary calcification.

Further studies such as the Brazilian Renagel and Calcium trial³⁴ and the Dialysis Clinical Outcomes Revisited trial failed to show a significant long-term benefit of sevelamer over calcium-based binders. However, a secondary statistical analysis of the latter study showed possible benefit of sevelamer over calcium acetate among those age 65 and older.³⁵

To understand how sevelamer could affect vascular calcification, Yilmaz et al³⁶ compared the effects of sevelamer vs calcium acetate on FGF23 and fetuin A levels. Fetuin A is an important inhibitor of vascular calcification and is progressively diminished in kidney disease, leading to accelerated calcification.³⁷ Patients on sevelamer had higher levels of fetuin A than their counterparts on calcium acetate.³⁷ The authors proposed increased fetuin A levels as a mechanism for decreased vascular calcification.

In summary, some studies suggest that sevelamer may offer the advantage of decreasing vascular calcification, but the data are mixed and do not provide a solid answer. The main disadvantages of sevelamer are a high pill burden and side effects of nausea and dyspepsia.

Lanthanum, a metallic element, was approved as a phosphorus binder by the FDA in 2008. It comes as a chewable tablet and offers the advantage of requiring the patient to take fewer pills than sevelamer and calcium-based binders.

Sucroferric oxyhydroxide comes as a chewable tablet. It was approved by the FDA in 2013. Although each tablet contains 500 mg of iron, it has not been shown to improve iron markers. In terms of phosphorus-lowering ability, it has been shown to be noninferior to sevelamer.³⁹ Advantages include a significantly lower pill burden. Disadvantages include gastrointestinal side effects such as diarrhea and nausea and the drug’s high cost.

Ferric citrate was approved by the FDA in 2014, and 1 g delivers 210 mg of elemental iron. The main advantage of ferric citrate is its ability to increase iron markers. The phase 3 trial that demonstrated its efficacy as a binder showed an increase in ferritin compared with the active control.⁴⁰ The study also showed a decrease in the need to use intravenous iron and erythropoesis-stimulating agents. This was thought to be due to improved iron stores, leading to decreased erythropoietin resistance.⁴¹

The mean number of ferric citrate tablets needed to achieve the desired phosphorus-lowering effect was 8 per day, containing 1,680 mg of iron. In comparison, oral ferrous sulfate typically provides 210 mg of iron per day.⁴²

Disadvantages of ferric citrate include high pill burden, high cost, and gastrointestinal side effects such as nausea and constipation.

Chitosan binds salivary phosphorus. It can potentially be used, but it is not approved, and its efficacy in lowering serum phosphorus remains unclear.⁴³

CHOOSING THE APPROPRIATE PHOSPHORUS BINDER

The choice of phosphorus binder is based on the patient’s serum calcium level and iron stores and on the drug’s side effect profile, iron pill burden, and cost. Involving patients in the choice after discussing potential side effects, pill burden, and cost is important for shared decision-making and could play a role in improving adherence.

Phosphorus binders are a major portion of the pill burden in patients with end-stage renal disease, possibly affecting patient adherence. The cost of phosphorus binders is estimated at half a billion dollars annually, underlining the significant economic impact of phosphorus control.¹¹

Calcium-based binders should be the first choice when there is secondary hyperparathyroidism without hypercalcemia. There is no clear evidence regarding the benefit of correcting hypocalcemia, but KDIGO recommends keeping the serum calcium level within the reference range. KDIGO also recommends restricting calcium-based binders in persistent hypercalcemia, arterial calcification, and adynamic bone disease. This recommendation is largely based on expert opinion.

Noncalcium-based binders, which in theory might prevent vascular calcification, should be considered for patients with at least 1 of the following⁴⁴:

• Complicated diabetes mellitus
• Vascular or valvular calcification
• Persistent inflammation.

Noncalcium-based binders are also preferred in low bone-turnover states such as adynamic bone disease, as elevated calcium can inhibit parathyroid hormone.

However, the advantage of noncalcium-based binders regarding vascular calcification is largely theoretical and has not been proven clinically. Indeed, there are data comparing long-term outcomes of the different classes of phosphorus binders, but studies were limited by short follow-up, and individual studies have lacked power to detect statistical significance between two classes of binders on long-term outcomes. Meta-analyses have provided conflicting data, with some suggesting better outcomes with sevelamer than with calcium-based binders, and with others failing to show any difference.⁴⁵

Because iron deficiency is common in kidney disease, ferric citrate, which can improve iron markers, may be a suitable option, provided its cost is covered by insurance.

SPECIAL CIRCUMSTANCES FOR THE USE OF PHOSPHORUS BINDERS

Tumor lysis syndrome

Tumor lysis syndrome occurs when tumor cells release their contents into the bloodstream, either spontaneously or in response to therapy, leading to the characteristic findings of hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia.⁴⁶ Phosphorus binders in conjunction with intravenous hydration are used to treat hyperphosphatemia, but evidence about their efficacy in this setting is limited.

Hypocalcemia in tumor lysis syndrome is usually not treated unless symptomatic, as the calcium-phosphorus product can increase, leading to calcium phosphate crystallization. When the calcium-phosphorus product is greater than 60, there is a higher risk of calcium phosphate deposition in the renal tubules that can lead to acute renal failure in tumor lysis syndrome.⁴⁷ To lower the risk of calcium phosphate crystallization, calcium-based binders should be avoided in tumor lysis syndrome.

Total parenteral nutrition

Since patients on total parenteral nutrition do not eat, phosphorus binders are considered ineffective; there are no concrete data showing that phosphorus binders are effective in these patients.⁴⁸ In patients with kidney disease, the phosphorus content in the parenteral nutrition formulation must be reduced.

Pregnancy

Data on phosphorus binders in pregnancy are limited. Calcium can cross the placenta. Calcium carbonate can be used in pregnancy, and fetal harm is not expected if calcium concentrations are within normal limits.⁴⁹ Calcium acetate, sevelamer, and lanthanum are considered pregnancy category C drugs. Patients with advanced chronic kidney disease and end-stage renal disease who become pregnant must receive specialized obstetric care for high-risk pregnancy.

FUTURE DIRECTIONS

Future therapies may target FGF23 and other inflammatory markers that are up-regulated in renal hyperparathyroidism. However, trials studying these markers are needed to provide a better understanding of their role in bone mineral and cardiovascular health and in overall long-term outcomes. Additionally, randomized controlled trials are needed to study long-term nonsurrogate outcomes such as reduction in cardiovascular disease and rates of overall mortality.

The balance between dietary intake and excretion of phosphorus can be impaired in patients with decreased renal function, leading to hyperphosphatemia. Many patients with end-stage renal disease on dialysis require phosphorus-binding drugs to control their serum phosphorus levels.

See related editorial and article

In this review, we discuss the pathophysiology of hyperphosphatemia in kidney disease, its consequences, and how to control it, focusing on the different classes of phosphorus binders.

ROLE OF THE INTERNIST

With kidney disease common and on the increase,¹ nephrologists and internists need to work together to provide optimal care.

Further, many internists in managed care plans and accountable care organizations now handle many tasks previously left to specialists—including prescribing and managing phosphorus binders in patients with kidney disease.

PATHOPHYSIOLOGY OF HYPERPHOSPHATEMIA

The pathophysiology of bone mineral disorders in kidney disease is complex. To simplify the discussion, we will address it in 3 parts:

• Phosphorus balance
• The interplay of hormones, including fibro­blast growth factor 23 (FGF23)
• The mechanism of hyperphosphatemia in kidney disease.

Phosphorus balance

Phosphorus is a macronutrient essential for a range of cellular functions that include structure, energy production, metabolism, and cell signaling. It exists primarily in the form of inorganic phosphate.

An average Western diet provides 20 mg of phosphorus per kilogram of body weight per day. Of this, 13 mg/kg is absorbed, and the rest is excreted in the feces.²

Absorption of dietary phosphorus occurs mainly in the jejunum. It is mediated by both a paracellular sodium-independent pathway (driven by high intraluminal phosphorus content) and by active sodium-dependent cotransporters. It is also influenced by diet and promoted by active vitamin D (1,25 dihydroxyvitamin D₃, also called calcitriol).³

Absorbed phosphorus enters the extracellular fluid and shifts in and out of the skeleton under the influence of parathyroid hormone.

Phosphorus excretion is handled almost entirely by the kidneys. Phosphorus is freely filtered at the glomerulus and reabsorbed mainly in the proximal tubule by sodium-phosphate cotransporters.

Normally, when phosphorus intake is adequate, most of the filtered phosphorus is reabsorbed and only 10% to 20% is excreted in the urine. However, the threshold for phosphorus reabsorption in the proximal tubule is influenced by parathyroid hormone, FGF23, and dietary phosphorus intake: low serum phosphate levels lead to an increase in the synthesis of sodium-phosphorus cotransporters, resulting in increased (nearly complete) proximal reabsorption and an increase in the serum phosphorus concentration.⁴ Conversely, both parathyroid hormone and FGF23 are phosphaturic and decrease the number of phosphorus transporters, which in turn leads to increased phosphorus excretion and a decrease in serum phosphorus concentration.⁵

Interplay of hormones

FGF23 is a phosphaturic glycoprotein secreted by osteoblasts and osteocytes. It acts by binding to fibroblastic growth receptor 1 in the presence of its coreceptor, the Klotho protein.⁶

FGF23 is regulated by serum phosphorus levels and plays a major role in the response to elevated serum phosphorus. It causes a direct increase in urinary phosphorus excretion, a decrease in intestinal phosphorus absorption (indirectly via inhibition of calcitriol), and decreased bone resorption via a decrease in parathyroid hormone production.⁷

Mechanism of hyperphosphatemia in kidney disease

In chronic kidney disease, phosphorus retention can trigger secondary hyperparathyroidism, as rising phosphorus levels stimulate FGF23. In the early stages of chronic kidney disease, this response can correct the phosphorus levels, but with several consequences:

• Decreased calcitriol due to its inhibition by FGF23⁹
• Hypocalcemia due to decreased calcitriol (leading to decreased intestinal calcium absorption) and calcium binding of retained phosphorus
• Elevated parathyroid hormone due to low calcitriol levels (lack of inhibitory feedback by calcitriol), hyperphosphatemia, and hypocalcemia (direct parathyroid hormone stimulation).

As the elevated phosphorus level is likely to be the triggering event behind secondary renal hyperparathyroidism, it needs to be controlled. This is accomplished by restricting dietary phosphorus and using phosphorus binders.

HYPERPHOSPHATEMIA MAY LEAD TO VASCULAR CALCIFICATION

Elevated serum phosphorus levels (normal range 2.48–4.65 mg/dL in adults¹¹) are associated with cardiovascular calcification and subsequent increases in mortality and morbidity rates. Elevations in serum phosphorus and calcium levels are associated with progression in vascular calcification¹² and likely account for the accelerated vascular calcification that is seen in kidney disease.¹³

Hyperphosphatemia has been identified as an independent risk factor for death in patients with end-stage renal disease,¹⁴ but that relationship is less clear in patients with chronic kidney disease. A study in patients with chronic kidney disease and not on dialysis found a lower mortality rate in those who were prescribed phosphorus binders,¹⁵ but the study was criticized for limitations in its design.

Hyperphosphatemia can also lead to adverse effects on bone health due to complications such as renal osteodystrophy.

However, in its 2017 update, the Kidney Disease: Improving Global Outcomes (KDIGO) program only “suggests” lowering elevated phosphorus levels “toward” the normal range in patients with chronic kidney disease stages G3a through G5D, ie, those with glomerular filtration rates less than 60 mL/min/1.73 m², including those on dialysis. The recommendation is graded 2C, ie, weak, based on low-quality evidence (https://kdigo.org/guidelines/ckd-mbd).

DIETARY RESTRICTION OF PHOSPHORUS

Diet is the major source of phosphorus intake. The average daily phosphorus consumption is  20 mg/kg, or 1,400 mg, and protein is the major source of dietary phosphorus.

In patients with stage 4 or 5 chronic kidney disease, the Kidney Disease Outcomes Quality Initiative recommends limiting protein intake to 0.6 mg/kg/day.¹⁶ However, in patients on hemodialysis, they recommend increasing protein intake to 1.1 mg/kg/day while limiting phosphorus intake to about 800 to 1,000 mg/day. This poses a challenge, as limiting phosphorus intake can reduce protein intake.

Sources of protein can be broadly classified as plant-based or animal-based. Animal protein contains organic phosphorus, which is easily absorbed.¹⁸ Plant protein may not be absorbed as easily.

Moe et al¹⁹ studied the importance of the protein source of phosphorus after 7 days of controlled diets. Despite equivalent protein and phosphorus concentrations in the vegetarian and meat-based diets, participants on the vegetarian diet had lower serum phosphorus levels, a trend toward lower 24-hour urinary phosphorus excretion, and significantly lower FGF23 levels than those on the meat-based diet. This suggests that a vegetarian diet may have advantages in terms of preventing hyperphosphatemia.

Another measure to reduce phosphorus absorption from meat is to boil it, which reduces the phosphorus content by 50%.²⁰

Processed foods containing additives and preservatives are very high in phosphorus²¹ and should be avoided, particularly as there is no mandate to label phosphorus content in food.

PHOSPHORUS AND DIALYSIS

Although hemodialysis removes phosphorus, it does not remove enough to keep levels within normal limits. Indeed, even when patients adhere to a daily phosphorus limit of 1,000 mg, phosphorus accumulates. If 70% of the phosphorus in the diet is absorbed, this is 4,500 to 5,000 mg in a week. A 4-hour hemodialysis session will remove only 1,000 mg of phosphorus, which equals about 3,000 mg for patients undergoing dialysis 3 times a week,²² far less than phosphorus absorption.

In patients on continuous ambulatory peritoneal dialysis, a daily regimen of 4 exchanges of 2 L per exchange removes about 200 mg of phosphorus per day. In a 2012 study, patients on nocturnal dialysis or home dialysis involving longer session length had greater lowering of phosphorus levels than patients undergoing routine hemodialysis.²³

Hence, phosphorus binders are often necessary in patients on routine hemodialysis or peritoneal dialysis.

PHOSPHORUS BINDERS

Phosphorus binders reduce serum phosphorus levels by binding with ingested phosphorus in the gastrointestinal tract and forming insoluble complexes that are not absorbed. For this reason they are much more effective when taken with meals. Phosphorus binders come in different formulations: pills, capsules, chewable tablets, liquids, and even powders that can be sprinkled on food.

The potency of each binder is quantified by its “phosphorus binder equivalent dose,” ie, its binding capacity compared with that of calcium carbonate as a reference.²⁴

Phosphorus binders are broadly divided into those that contain calcium and those that do not.

Calcium-containing binders

The 2 most commonly used preparations are calcium carbonate (eg, Tums) and calcium acetate (eg, Phoslo). While these are relatively safe, some studies suggest that their use can lead to accelerated vascular calcification.²⁵

According to KDIGO,²⁶ calcium-containing binders should be avoided in hypercalcemia and adynamic bone disease. Additionally, the daily elemental calcium intake from binders should be limited to 1,500 mg, with a total daily intake that does not exceed 2,000 mg.

The elemental calcium content of calcium carbonate is about 40% of its weight (eg, 200 mg of elemental calcium in a 500-mg tablet of Tums), while the elemental calcium content of calcium acetate is about 25%. Therefore, a patient who needs 6 g of calcium carbonate for efficacy will be ingesting 2.4 g of elemental calcium per day, and that exceeds the recommended daily maximum. The main advantage of calcium carbonate is its low cost and easy availability. Commonly reported side effects include nausea and constipation.

A less commonly used calcium-based binder is calcium citrate (eg, Calcitrate). It should, however, be avoided in chronic kidney disease because of the risk of aluminum accumulation. Calcium citrate can enhance intestinal absorption of aluminum from dietary sources, as aluminum can form complexes with citrate.²⁷

Calcium-free binders

There are several calcium-free binders. Some are based on metals such as aluminum, magnesium, iron, and lanthanum; others, such as sevelamer, are resin-based.

Aluminum- and magnesium-based binders are generally not used long-term in kidney disease because of the toxicity associated with aluminum and magnesium accumulation. However, aluminum hydroxide has an off-label use as a phosphorus binder in the acute setting, particularly when serum phosphorus levels are above 7 mg/dL.²⁸ The dose is 300 to 600 mg 3 times daily with meals for a maximum of 4 weeks.

Sevelamer. Approved by the US Food and Drug Administration (FDA) in 1998, sevelamer acts by trapping phosphorus through ion exchange and hydrogen binding. It has the advantage of being calcium-free, which makes it particularly desirable in patients with hypercalcemia.

The Renagel in New Dialysis²⁵ and Treat-To-Goal²⁹ studies were randomized controlled trials that looked at the effects of sevelamer vs calcium-based binders on the risk of vascular calcification. The primary end points were serum phosphorus and calcium levels, while the secondary end points were coronary artery calcification on computed tomography and thoracic vertebral bone density. Both studies demonstrated a higher risk of vascular calcification with the calcium-based binders.

Another possible benefit of sevelamer is an improvement in lipid profile. Sevelamer lowers total cholesterol and low-density lipoprotein cholesterol levels without affecting high-density lipoprotein cholesterol or triglyceride levels.³⁰ This is likely due to its bile acid-binding effect.³¹ Sevelamer has also been shown to lower C-reactive protein levels.³² While the cardiovascular profile appears to be improved with the treatment, there are no convincing data to confirm that those properties translate to a proven independent survival benefit.

The Calcium Acetate Renagel Evaluation³³ was a randomized controlled study comparing sevelamer and calcium acetate. The authors attempted to control for the lipid-lowering effects of sevelamer by giving atorvastatin to all patients in both groups who had a low-density lipoprotein level greater than 70 mg/dL. The study found sevelamer to be not inferior to calcium acetate in terms of mortality and coronary calcification.

Further studies such as the Brazilian Renagel and Calcium trial³⁴ and the Dialysis Clinical Outcomes Revisited trial failed to show a significant long-term benefit of sevelamer over calcium-based binders. However, a secondary statistical analysis of the latter study showed possible benefit of sevelamer over calcium acetate among those age 65 and older.³⁵

To understand how sevelamer could affect vascular calcification, Yilmaz et al³⁶ compared the effects of sevelamer vs calcium acetate on FGF23 and fetuin A levels. Fetuin A is an important inhibitor of vascular calcification and is progressively diminished in kidney disease, leading to accelerated calcification.³⁷ Patients on sevelamer had higher levels of fetuin A than their counterparts on calcium acetate.³⁷ The authors proposed increased fetuin A levels as a mechanism for decreased vascular calcification.

In summary, some studies suggest that sevelamer may offer the advantage of decreasing vascular calcification, but the data are mixed and do not provide a solid answer. The main disadvantages of sevelamer are a high pill burden and side effects of nausea and dyspepsia.

Lanthanum, a metallic element, was approved as a phosphorus binder by the FDA in 2008. It comes as a chewable tablet and offers the advantage of requiring the patient to take fewer pills than sevelamer and calcium-based binders.

Sucroferric oxyhydroxide comes as a chewable tablet. It was approved by the FDA in 2013. Although each tablet contains 500 mg of iron, it has not been shown to improve iron markers. In terms of phosphorus-lowering ability, it has been shown to be noninferior to sevelamer.³⁹ Advantages include a significantly lower pill burden. Disadvantages include gastrointestinal side effects such as diarrhea and nausea and the drug’s high cost.

Ferric citrate was approved by the FDA in 2014, and 1 g delivers 210 mg of elemental iron. The main advantage of ferric citrate is its ability to increase iron markers. The phase 3 trial that demonstrated its efficacy as a binder showed an increase in ferritin compared with the active control.⁴⁰ The study also showed a decrease in the need to use intravenous iron and erythropoesis-stimulating agents. This was thought to be due to improved iron stores, leading to decreased erythropoietin resistance.⁴¹

The mean number of ferric citrate tablets needed to achieve the desired phosphorus-lowering effect was 8 per day, containing 1,680 mg of iron. In comparison, oral ferrous sulfate typically provides 210 mg of iron per day.⁴²

Disadvantages of ferric citrate include high pill burden, high cost, and gastrointestinal side effects such as nausea and constipation.

Chitosan binds salivary phosphorus. It can potentially be used, but it is not approved, and its efficacy in lowering serum phosphorus remains unclear.⁴³

CHOOSING THE APPROPRIATE PHOSPHORUS BINDER

The choice of phosphorus binder is based on the patient’s serum calcium level and iron stores and on the drug’s side effect profile, iron pill burden, and cost. Involving patients in the choice after discussing potential side effects, pill burden, and cost is important for shared decision-making and could play a role in improving adherence.

Phosphorus binders are a major portion of the pill burden in patients with end-stage renal disease, possibly affecting patient adherence. The cost of phosphorus binders is estimated at half a billion dollars annually, underlining the significant economic impact of phosphorus control.¹¹

Calcium-based binders should be the first choice when there is secondary hyperparathyroidism without hypercalcemia. There is no clear evidence regarding the benefit of correcting hypocalcemia, but KDIGO recommends keeping the serum calcium level within the reference range. KDIGO also recommends restricting calcium-based binders in persistent hypercalcemia, arterial calcification, and adynamic bone disease. This recommendation is largely based on expert opinion.

Noncalcium-based binders, which in theory might prevent vascular calcification, should be considered for patients with at least 1 of the following⁴⁴:

• Complicated diabetes mellitus
• Vascular or valvular calcification
• Persistent inflammation.

Noncalcium-based binders are also preferred in low bone-turnover states such as adynamic bone disease, as elevated calcium can inhibit parathyroid hormone.

However, the advantage of noncalcium-based binders regarding vascular calcification is largely theoretical and has not been proven clinically. Indeed, there are data comparing long-term outcomes of the different classes of phosphorus binders, but studies were limited by short follow-up, and individual studies have lacked power to detect statistical significance between two classes of binders on long-term outcomes. Meta-analyses have provided conflicting data, with some suggesting better outcomes with sevelamer than with calcium-based binders, and with others failing to show any difference.⁴⁵

Because iron deficiency is common in kidney disease, ferric citrate, which can improve iron markers, may be a suitable option, provided its cost is covered by insurance.

SPECIAL CIRCUMSTANCES FOR THE USE OF PHOSPHORUS BINDERS

Tumor lysis syndrome

Tumor lysis syndrome occurs when tumor cells release their contents into the bloodstream, either spontaneously or in response to therapy, leading to the characteristic findings of hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia.⁴⁶ Phosphorus binders in conjunction with intravenous hydration are used to treat hyperphosphatemia, but evidence about their efficacy in this setting is limited.

Hypocalcemia in tumor lysis syndrome is usually not treated unless symptomatic, as the calcium-phosphorus product can increase, leading to calcium phosphate crystallization. When the calcium-phosphorus product is greater than 60, there is a higher risk of calcium phosphate deposition in the renal tubules that can lead to acute renal failure in tumor lysis syndrome.⁴⁷ To lower the risk of calcium phosphate crystallization, calcium-based binders should be avoided in tumor lysis syndrome.

Total parenteral nutrition

Since patients on total parenteral nutrition do not eat, phosphorus binders are considered ineffective; there are no concrete data showing that phosphorus binders are effective in these patients.⁴⁸ In patients with kidney disease, the phosphorus content in the parenteral nutrition formulation must be reduced.

Pregnancy

Data on phosphorus binders in pregnancy are limited. Calcium can cross the placenta. Calcium carbonate can be used in pregnancy, and fetal harm is not expected if calcium concentrations are within normal limits.⁴⁹ Calcium acetate, sevelamer, and lanthanum are considered pregnancy category C drugs. Patients with advanced chronic kidney disease and end-stage renal disease who become pregnant must receive specialized obstetric care for high-risk pregnancy.

FUTURE DIRECTIONS

Future therapies may target FGF23 and other inflammatory markers that are up-regulated in renal hyperparathyroidism. However, trials studying these markers are needed to provide a better understanding of their role in bone mineral and cardiovascular health and in overall long-term outcomes. Additionally, randomized controlled trials are needed to study long-term nonsurrogate outcomes such as reduction in cardiovascular disease and rates of overall mortality.

The balance between dietary intake and excretion of phosphorus can be impaired in patients with decreased renal function, leading to hyperphosphatemia. Many patients with end-stage renal disease on dialysis require phosphorus-binding drugs to control their serum phosphorus levels.

See related editorial and article

In this review, we discuss the pathophysiology of hyperphosphatemia in kidney disease, its consequences, and how to control it, focusing on the different classes of phosphorus binders.

ROLE OF THE INTERNIST

With kidney disease common and on the increase,¹ nephrologists and internists need to work together to provide optimal care.

Further, many internists in managed care plans and accountable care organizations now handle many tasks previously left to specialists—including prescribing and managing phosphorus binders in patients with kidney disease.

PATHOPHYSIOLOGY OF HYPERPHOSPHATEMIA

The pathophysiology of bone mineral disorders in kidney disease is complex. To simplify the discussion, we will address it in 3 parts:

• Phosphorus balance
• The interplay of hormones, including fibro­blast growth factor 23 (FGF23)
• The mechanism of hyperphosphatemia in kidney disease.

Phosphorus balance

Phosphorus is a macronutrient essential for a range of cellular functions that include structure, energy production, metabolism, and cell signaling. It exists primarily in the form of inorganic phosphate.

An average Western diet provides 20 mg of phosphorus per kilogram of body weight per day. Of this, 13 mg/kg is absorbed, and the rest is excreted in the feces.²

Absorption of dietary phosphorus occurs mainly in the jejunum. It is mediated by both a paracellular sodium-independent pathway (driven by high intraluminal phosphorus content) and by active sodium-dependent cotransporters. It is also influenced by diet and promoted by active vitamin D (1,25 dihydroxyvitamin D₃, also called calcitriol).³

Absorbed phosphorus enters the extracellular fluid and shifts in and out of the skeleton under the influence of parathyroid hormone.

Phosphorus excretion is handled almost entirely by the kidneys. Phosphorus is freely filtered at the glomerulus and reabsorbed mainly in the proximal tubule by sodium-phosphate cotransporters.

Normally, when phosphorus intake is adequate, most of the filtered phosphorus is reabsorbed and only 10% to 20% is excreted in the urine. However, the threshold for phosphorus reabsorption in the proximal tubule is influenced by parathyroid hormone, FGF23, and dietary phosphorus intake: low serum phosphate levels lead to an increase in the synthesis of sodium-phosphorus cotransporters, resulting in increased (nearly complete) proximal reabsorption and an increase in the serum phosphorus concentration.⁴ Conversely, both parathyroid hormone and FGF23 are phosphaturic and decrease the number of phosphorus transporters, which in turn leads to increased phosphorus excretion and a decrease in serum phosphorus concentration.⁵

Interplay of hormones

FGF23 is a phosphaturic glycoprotein secreted by osteoblasts and osteocytes. It acts by binding to fibroblastic growth receptor 1 in the presence of its coreceptor, the Klotho protein.⁶

FGF23 is regulated by serum phosphorus levels and plays a major role in the response to elevated serum phosphorus. It causes a direct increase in urinary phosphorus excretion, a decrease in intestinal phosphorus absorption (indirectly via inhibition of calcitriol), and decreased bone resorption via a decrease in parathyroid hormone production.⁷

Mechanism of hyperphosphatemia in kidney disease

In chronic kidney disease, phosphorus retention can trigger secondary hyperparathyroidism, as rising phosphorus levels stimulate FGF23. In the early stages of chronic kidney disease, this response can correct the phosphorus levels, but with several consequences:

• Decreased calcitriol due to its inhibition by FGF23⁹
• Hypocalcemia due to decreased calcitriol (leading to decreased intestinal calcium absorption) and calcium binding of retained phosphorus
• Elevated parathyroid hormone due to low calcitriol levels (lack of inhibitory feedback by calcitriol), hyperphosphatemia, and hypocalcemia (direct parathyroid hormone stimulation).

As the elevated phosphorus level is likely to be the triggering event behind secondary renal hyperparathyroidism, it needs to be controlled. This is accomplished by restricting dietary phosphorus and using phosphorus binders.

HYPERPHOSPHATEMIA MAY LEAD TO VASCULAR CALCIFICATION

Elevated serum phosphorus levels (normal range 2.48–4.65 mg/dL in adults¹¹) are associated with cardiovascular calcification and subsequent increases in mortality and morbidity rates. Elevations in serum phosphorus and calcium levels are associated with progression in vascular calcification¹² and likely account for the accelerated vascular calcification that is seen in kidney disease.¹³

Hyperphosphatemia has been identified as an independent risk factor for death in patients with end-stage renal disease,¹⁴ but that relationship is less clear in patients with chronic kidney disease. A study in patients with chronic kidney disease and not on dialysis found a lower mortality rate in those who were prescribed phosphorus binders,¹⁵ but the study was criticized for limitations in its design.

Hyperphosphatemia can also lead to adverse effects on bone health due to complications such as renal osteodystrophy.

However, in its 2017 update, the Kidney Disease: Improving Global Outcomes (KDIGO) program only “suggests” lowering elevated phosphorus levels “toward” the normal range in patients with chronic kidney disease stages G3a through G5D, ie, those with glomerular filtration rates less than 60 mL/min/1.73 m², including those on dialysis. The recommendation is graded 2C, ie, weak, based on low-quality evidence (https://kdigo.org/guidelines/ckd-mbd).

DIETARY RESTRICTION OF PHOSPHORUS

Diet is the major source of phosphorus intake. The average daily phosphorus consumption is  20 mg/kg, or 1,400 mg, and protein is the major source of dietary phosphorus.

In patients with stage 4 or 5 chronic kidney disease, the Kidney Disease Outcomes Quality Initiative recommends limiting protein intake to 0.6 mg/kg/day.¹⁶ However, in patients on hemodialysis, they recommend increasing protein intake to 1.1 mg/kg/day while limiting phosphorus intake to about 800 to 1,000 mg/day. This poses a challenge, as limiting phosphorus intake can reduce protein intake.

Sources of protein can be broadly classified as plant-based or animal-based. Animal protein contains organic phosphorus, which is easily absorbed.¹⁸ Plant protein may not be absorbed as easily.

Moe et al¹⁹ studied the importance of the protein source of phosphorus after 7 days of controlled diets. Despite equivalent protein and phosphorus concentrations in the vegetarian and meat-based diets, participants on the vegetarian diet had lower serum phosphorus levels, a trend toward lower 24-hour urinary phosphorus excretion, and significantly lower FGF23 levels than those on the meat-based diet. This suggests that a vegetarian diet may have advantages in terms of preventing hyperphosphatemia.

Another measure to reduce phosphorus absorption from meat is to boil it, which reduces the phosphorus content by 50%.²⁰

Processed foods containing additives and preservatives are very high in phosphorus²¹ and should be avoided, particularly as there is no mandate to label phosphorus content in food.

PHOSPHORUS AND DIALYSIS

Although hemodialysis removes phosphorus, it does not remove enough to keep levels within normal limits. Indeed, even when patients adhere to a daily phosphorus limit of 1,000 mg, phosphorus accumulates. If 70% of the phosphorus in the diet is absorbed, this is 4,500 to 5,000 mg in a week. A 4-hour hemodialysis session will remove only 1,000 mg of phosphorus, which equals about 3,000 mg for patients undergoing dialysis 3 times a week,²² far less than phosphorus absorption.

In patients on continuous ambulatory peritoneal dialysis, a daily regimen of 4 exchanges of 2 L per exchange removes about 200 mg of phosphorus per day. In a 2012 study, patients on nocturnal dialysis or home dialysis involving longer session length had greater lowering of phosphorus levels than patients undergoing routine hemodialysis.²³

Hence, phosphorus binders are often necessary in patients on routine hemodialysis or peritoneal dialysis.

PHOSPHORUS BINDERS

Phosphorus binders reduce serum phosphorus levels by binding with ingested phosphorus in the gastrointestinal tract and forming insoluble complexes that are not absorbed. For this reason they are much more effective when taken with meals. Phosphorus binders come in different formulations: pills, capsules, chewable tablets, liquids, and even powders that can be sprinkled on food.

The potency of each binder is quantified by its “phosphorus binder equivalent dose,” ie, its binding capacity compared with that of calcium carbonate as a reference.²⁴

Phosphorus binders are broadly divided into those that contain calcium and those that do not.

Calcium-containing binders

The 2 most commonly used preparations are calcium carbonate (eg, Tums) and calcium acetate (eg, Phoslo). While these are relatively safe, some studies suggest that their use can lead to accelerated vascular calcification.²⁵

According to KDIGO,²⁶ calcium-containing binders should be avoided in hypercalcemia and adynamic bone disease. Additionally, the daily elemental calcium intake from binders should be limited to 1,500 mg, with a total daily intake that does not exceed 2,000 mg.

The elemental calcium content of calcium carbonate is about 40% of its weight (eg, 200 mg of elemental calcium in a 500-mg tablet of Tums), while the elemental calcium content of calcium acetate is about 25%. Therefore, a patient who needs 6 g of calcium carbonate for efficacy will be ingesting 2.4 g of elemental calcium per day, and that exceeds the recommended daily maximum. The main advantage of calcium carbonate is its low cost and easy availability. Commonly reported side effects include nausea and constipation.

A less commonly used calcium-based binder is calcium citrate (eg, Calcitrate). It should, however, be avoided in chronic kidney disease because of the risk of aluminum accumulation. Calcium citrate can enhance intestinal absorption of aluminum from dietary sources, as aluminum can form complexes with citrate.²⁷

Calcium-free binders

There are several calcium-free binders. Some are based on metals such as aluminum, magnesium, iron, and lanthanum; others, such as sevelamer, are resin-based.

Aluminum- and magnesium-based binders are generally not used long-term in kidney disease because of the toxicity associated with aluminum and magnesium accumulation. However, aluminum hydroxide has an off-label use as a phosphorus binder in the acute setting, particularly when serum phosphorus levels are above 7 mg/dL.²⁸ The dose is 300 to 600 mg 3 times daily with meals for a maximum of 4 weeks.

Sevelamer. Approved by the US Food and Drug Administration (FDA) in 1998, sevelamer acts by trapping phosphorus through ion exchange and hydrogen binding. It has the advantage of being calcium-free, which makes it particularly desirable in patients with hypercalcemia.

The Renagel in New Dialysis²⁵ and Treat-To-Goal²⁹ studies were randomized controlled trials that looked at the effects of sevelamer vs calcium-based binders on the risk of vascular calcification. The primary end points were serum phosphorus and calcium levels, while the secondary end points were coronary artery calcification on computed tomography and thoracic vertebral bone density. Both studies demonstrated a higher risk of vascular calcification with the calcium-based binders.

Another possible benefit of sevelamer is an improvement in lipid profile. Sevelamer lowers total cholesterol and low-density lipoprotein cholesterol levels without affecting high-density lipoprotein cholesterol or triglyceride levels.³⁰ This is likely due to its bile acid-binding effect.³¹ Sevelamer has also been shown to lower C-reactive protein levels.³² While the cardiovascular profile appears to be improved with the treatment, there are no convincing data to confirm that those properties translate to a proven independent survival benefit.

The Calcium Acetate Renagel Evaluation³³ was a randomized controlled study comparing sevelamer and calcium acetate. The authors attempted to control for the lipid-lowering effects of sevelamer by giving atorvastatin to all patients in both groups who had a low-density lipoprotein level greater than 70 mg/dL. The study found sevelamer to be not inferior to calcium acetate in terms of mortality and coronary calcification.

Further studies such as the Brazilian Renagel and Calcium trial³⁴ and the Dialysis Clinical Outcomes Revisited trial failed to show a significant long-term benefit of sevelamer over calcium-based binders. However, a secondary statistical analysis of the latter study showed possible benefit of sevelamer over calcium acetate among those age 65 and older.³⁵

To understand how sevelamer could affect vascular calcification, Yilmaz et al³⁶ compared the effects of sevelamer vs calcium acetate on FGF23 and fetuin A levels. Fetuin A is an important inhibitor of vascular calcification and is progressively diminished in kidney disease, leading to accelerated calcification.³⁷ Patients on sevelamer had higher levels of fetuin A than their counterparts on calcium acetate.³⁷ The authors proposed increased fetuin A levels as a mechanism for decreased vascular calcification.

In summary, some studies suggest that sevelamer may offer the advantage of decreasing vascular calcification, but the data are mixed and do not provide a solid answer. The main disadvantages of sevelamer are a high pill burden and side effects of nausea and dyspepsia.

Lanthanum, a metallic element, was approved as a phosphorus binder by the FDA in 2008. It comes as a chewable tablet and offers the advantage of requiring the patient to take fewer pills than sevelamer and calcium-based binders.

Sucroferric oxyhydroxide comes as a chewable tablet. It was approved by the FDA in 2013. Although each tablet contains 500 mg of iron, it has not been shown to improve iron markers. In terms of phosphorus-lowering ability, it has been shown to be noninferior to sevelamer.³⁹ Advantages include a significantly lower pill burden. Disadvantages include gastrointestinal side effects such as diarrhea and nausea and the drug’s high cost.

Ferric citrate was approved by the FDA in 2014, and 1 g delivers 210 mg of elemental iron. The main advantage of ferric citrate is its ability to increase iron markers. The phase 3 trial that demonstrated its efficacy as a binder showed an increase in ferritin compared with the active control.⁴⁰ The study also showed a decrease in the need to use intravenous iron and erythropoesis-stimulating agents. This was thought to be due to improved iron stores, leading to decreased erythropoietin resistance.⁴¹

The mean number of ferric citrate tablets needed to achieve the desired phosphorus-lowering effect was 8 per day, containing 1,680 mg of iron. In comparison, oral ferrous sulfate typically provides 210 mg of iron per day.⁴²

Disadvantages of ferric citrate include high pill burden, high cost, and gastrointestinal side effects such as nausea and constipation.

Chitosan binds salivary phosphorus. It can potentially be used, but it is not approved, and its efficacy in lowering serum phosphorus remains unclear.⁴³

CHOOSING THE APPROPRIATE PHOSPHORUS BINDER

The choice of phosphorus binder is based on the patient’s serum calcium level and iron stores and on the drug’s side effect profile, iron pill burden, and cost. Involving patients in the choice after discussing potential side effects, pill burden, and cost is important for shared decision-making and could play a role in improving adherence.

Phosphorus binders are a major portion of the pill burden in patients with end-stage renal disease, possibly affecting patient adherence. The cost of phosphorus binders is estimated at half a billion dollars annually, underlining the significant economic impact of phosphorus control.¹¹

Calcium-based binders should be the first choice when there is secondary hyperparathyroidism without hypercalcemia. There is no clear evidence regarding the benefit of correcting hypocalcemia, but KDIGO recommends keeping the serum calcium level within the reference range. KDIGO also recommends restricting calcium-based binders in persistent hypercalcemia, arterial calcification, and adynamic bone disease. This recommendation is largely based on expert opinion.

Noncalcium-based binders, which in theory might prevent vascular calcification, should be considered for patients with at least 1 of the following⁴⁴:

• Complicated diabetes mellitus
• Vascular or valvular calcification
• Persistent inflammation.

Noncalcium-based binders are also preferred in low bone-turnover states such as adynamic bone disease, as elevated calcium can inhibit parathyroid hormone.

However, the advantage of noncalcium-based binders regarding vascular calcification is largely theoretical and has not been proven clinically. Indeed, there are data comparing long-term outcomes of the different classes of phosphorus binders, but studies were limited by short follow-up, and individual studies have lacked power to detect statistical significance between two classes of binders on long-term outcomes. Meta-analyses have provided conflicting data, with some suggesting better outcomes with sevelamer than with calcium-based binders, and with others failing to show any difference.⁴⁵

Because iron deficiency is common in kidney disease, ferric citrate, which can improve iron markers, may be a suitable option, provided its cost is covered by insurance.

SPECIAL CIRCUMSTANCES FOR THE USE OF PHOSPHORUS BINDERS

Tumor lysis syndrome

Tumor lysis syndrome occurs when tumor cells release their contents into the bloodstream, either spontaneously or in response to therapy, leading to the characteristic findings of hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia.⁴⁶ Phosphorus binders in conjunction with intravenous hydration are used to treat hyperphosphatemia, but evidence about their efficacy in this setting is limited.

Hypocalcemia in tumor lysis syndrome is usually not treated unless symptomatic, as the calcium-phosphorus product can increase, leading to calcium phosphate crystallization. When the calcium-phosphorus product is greater than 60, there is a higher risk of calcium phosphate deposition in the renal tubules that can lead to acute renal failure in tumor lysis syndrome.⁴⁷ To lower the risk of calcium phosphate crystallization, calcium-based binders should be avoided in tumor lysis syndrome.

Total parenteral nutrition

Since patients on total parenteral nutrition do not eat, phosphorus binders are considered ineffective; there are no concrete data showing that phosphorus binders are effective in these patients.⁴⁸ In patients with kidney disease, the phosphorus content in the parenteral nutrition formulation must be reduced.

Pregnancy

Data on phosphorus binders in pregnancy are limited. Calcium can cross the placenta. Calcium carbonate can be used in pregnancy, and fetal harm is not expected if calcium concentrations are within normal limits.⁴⁹ Calcium acetate, sevelamer, and lanthanum are considered pregnancy category C drugs. Patients with advanced chronic kidney disease and end-stage renal disease who become pregnant must receive specialized obstetric care for high-risk pregnancy.

FUTURE DIRECTIONS

Future therapies may target FGF23 and other inflammatory markers that are up-regulated in renal hyperparathyroidism. However, trials studying these markers are needed to provide a better understanding of their role in bone mineral and cardiovascular health and in overall long-term outcomes. Additionally, randomized controlled trials are needed to study long-term nonsurrogate outcomes such as reduction in cardiovascular disease and rates of overall mortality.

Phosphorus is essential for life. However, both low and high levels of phosphorus in the body have consequences, and its concentration in the blood is tightly regulated through dietary absorption, bone flux, and renal excretion and is influenced by calcitriol (1,25 hydroxyvitamin D₃), parathyroid hormone, and fibroblast growth factor 23 (FGF23).

See related articles by M. Shetty and A. Sekar

Sekar et al,¹ in this issue of the Journal, provide an extensive review of the pathophysiology of phosphorus metabolism and strategies to control phosphorus levels in patients with hyperphosphatemia and end-stage kidney disease.

PHOSPHORUS OR PHOSPHATE?

What's in a name? That which we call a rose
By any other word would smell as sweet.
—Shakespeare, Romeo and Juliet

The terms phosphate and phosphorus are often used interchangeably, though most writers still prefer phosphate over phosphorus.

The serum concentrations of phosphate and phosphorus are the same when expressed in millimoles per liter, as every mole of phosphate contains 1 mole of phosphorus, but not the same when expressed in milligrams per deciliter.² The molecular weight of phosphorus is 30.97, whereas the molecular weight of the phosphate ion (PO₄^3–) is 94.97—more than 3 times higher. Therefore, using these terms interchangeably in this context can lead to numerical error.³

Phosphorus, being highly reactive, does not exist by itself in nature and is typically present as phosphates in biologic systems. When describing phosphorus metabolism, the term phosphates should ideally be used because phosphates are the actual participants in the bodily processes. But in the clinical laboratory, all methods that measure serum phosphorus in fact measure inorganic phosphate and are expressed in terms of milligrams of phosphorus per deciliter rather than milligrams of phosphate per deciliter, and using these 2 terms interchangeably in clinical practice should not be of concern.⁴

THE PROBLEM

US adults typically ingest 1,200 mg of phosphorus each day, and about 60% to 70% of the ingested phosphorus is absorbed both by passive paracellular diffusion via tight junctions and by active transcellular transport via sodium-phosphate cotransport. The kidneys must excrete the same amount daily to maintain a steady state. As kidney function declines, phosphorus accumulates in the blood, leading to hyperphosphatemia.

Hyperphosphatemia is often asymptomatic, but it can cause generalized itching, red eyes, and adverse effects on the bone and parathyroid glands. Higher serum phosphorus levels have been shown to be associated with vascular calcification,⁵ cardiovascular events, and higher all-cause mortality rates in the general population,⁶ in patients with diabetes,⁷ and in those with chronic kidney disease.⁸ This association between higher serum phosphorus levels and the all-cause mortality rate led to the assumption that lowering serum phosphorus levels in these patients could reduce the rates of cardiovascular events and death, and to efforts to correct hyperphosphatemia.

Research into FGF23 continues, especially its role in cardiovascular complications of chronic kidney disease, as both phosphorus and FGF23 levels are elevated in chronic kidney disease and are implicated in poor clinical outcomes in these patients. However, both FGF23 and parathyroid hormone levels rise early in the course of kidney disease, long before overt hyperphosphatemia develops. Further, FGF23 rises earlier than parathyroid hormone and has been found to be an independent risk factor for cardiovascular events and death from any cause in end-stage kidney disease.⁹

Whether hyperphosphatemia is the culprit or merely an epiphenomenon of metabolic complications of chronic kidney disease is still unclear, as more molecules are being identified in the complex process of cardiovascular calcification.¹⁰

However, one thing is clear: vascular calcification is not just a simple precipitation of calcium and phosphorus. Instead, it is an active process that involves many regulators of mineral metabolism.¹⁰ The complex nature of this process is likely one of the reasons that evidence is conflicting¹¹ about the benefits of phosphorus binders in terms of cardiovascular events or all-cause mortality in these patients.

Reducing intake

Dietary phosphorus restriction is the first step in controlling serum phosphorus. But reducing phosphorus intake while otherwise trying to optimize the nutritional status can be challenging.

The recommended daily protein intake is 1.0 to 1.2 g/kg. But phosphorus is typically found in foods rich in proteins, and restricting protein severely can compromise nutritional status and may be as bad as elevated phosphate levels in terms of outcomes.

Although plant-based foods contain more phosphate per gram of protein (ie, they have a higher ratio of phosphorus to protein) than animal-based foods, the bioavailability of phosphorus from plant foods is lower. Phosphorus in plant-based foods is mainly in the form of phytate. Humans cannot hydrolyze phytate because we lack the phytase enzyme; hence, the phosphorus in plant-based foods is not well absorbed. Therefore, a vegetarian diet may be preferable and beneficial in patients with chronic kidney disease. A small study in humans showed that a vegetarian diet resulted in lower serum phosphorus and FGF23 levels, but the study was limited by its small sample size.¹²

Patients should be advised to avoid foods that have a high phosphate content, such as processed foods, fast foods, and cola beverages, which often have phosphate-based food additives.

Further, one should be cautious about using supplements with healthy-sounding names. A case in point is “vitamin water”: 12 oz of this fruit punch-flavored beverage contains 392 mg of phosphorus,¹³ and this alone would require 12 to 15 phosphate binder tablets to bind its phosphorus content.

In addition, many prescription drugs have significant amounts of phosphorus, and this is often unrecognized.

Sherman et al¹⁴ reviewed 200 of the most commonly prescribed drugs in dialysis patients and found that 23 (11.5%) of the drug labels listed phosphorus-containing ingredients, but the actual amount of phosphorus was not listed. The phosphorus content ranged from 1.4 mg (clonidine 0.2 mg, Blue Point Laboratories, Dublin, Ireland) to 111.5 mg (paroxetine 40 mg, GlaxoSmith Kline, Philadelphia, PA). The phosphorus content was inconsistent and varied with the dose of the agent, type of formulation (tablet or syrup), branded or generic formulation, and manufacturer.

Branded lisinopril (Merck, Kenilworth, NJ) had 21.4 mg of phosphorus per 10-mg dose, while a generic product (Blue Point Laboratories, Dublin, Ireland) had 32.6 mg. Different brands of generic amlodipine 10 mg varied in their phosphorus content from 8.6 mg (Lupin Pharmaceuticals, Mumbai, India) to 27.8 mg (Greenstone LLC, Peapack, NJ) to 40.1 mg (Qualitest Pharmaceuticals, Huntsville, AL. Rena-Vite (Cypress Pharmaceuticals, Madison, MS), a multivitamin marketed to patients with kidney disease, had 37.7 mg of phosphorus per tablet. Thus, just to bind the phosphorus content of these 3 tablets (lisinopril, amlodipine, and Rena-Vite), a patient could need at least 3 to 4 extra doses of phosphate binder.

The phosphate content of medications should be considered when prescribing. For example, Reno Caps (Nnodum Pharmaceuticals, Cincinnati, OH), another vitamin supplement, has only 1.7 mg of phosphorus per tablet and should be considered, especially in patients with poorly controlled serum phosphorus levels. However, the challenge is that medication labels do not provide the phosphorus content.

Reducing phosphorus absorption

Although these agents reduce serum phosphorus and help reduce symptoms, an important quality-of-life measure, it is uncertain whether they improve clinical outcomes.¹¹ To date, no specific phosphorus binder offers a survival benefit over placebo.¹¹

Based on the limited and conflicting evidence, the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, recently updated, suggest that oral phosphorus binders should be used in patients with hyperphosphatemia to lower serum phosphorus levels toward the normal range.¹⁵ They further recommend not exceeding 1,500 mg of elemental calcium per day if a calcium-based binder is used, and they recommend avoiding calcium-based binders in patients with hypercalcemia, adynamic bone disease, or vascular calcification.

Phosphorus binders may account for up to 50% of the daily pill burden and may contribute to poor medication adherence.¹⁶ Dialysis patients need to take a lot of these drugs: by weight, 5 to 6 pounds per year.

These drugs can bind and interfere with the absorption of other vital medications and so should be taken with meals and separately from other medications.

Removing phosphorus

Removal of phosphorus by adequate dialysis or kidney transplant is the final strategy.

New agents under study

To improve phosphorus control, other agents that inhibit absorption of phosphate are being investigated.

Nicotinamide reduces expression of the sodium-phosphorus cotransporter NTP2b. Its use in combination with a low-phosphorus diet and phosphorus binders may maximize reductions in phosphorus absorption and is being studied in the CKD Optimal Management With Binders and Nicotinamide (COMBINE) study.

Tenapanor, an inhibitor of the sodium-hydrogen transporter NHE3, has been shown in animal studies to increase fecal phosphate excretion and decrease urinary phosphate excretion17 but requires further evaluation.

Phosphorus is essential for life. However, both low and high levels of phosphorus in the body have consequences, and its concentration in the blood is tightly regulated through dietary absorption, bone flux, and renal excretion and is influenced by calcitriol (1,25 hydroxyvitamin D₃), parathyroid hormone, and fibroblast growth factor 23 (FGF23).

See related articles by M. Shetty and A. Sekar

Sekar et al,¹ in this issue of the Journal, provide an extensive review of the pathophysiology of phosphorus metabolism and strategies to control phosphorus levels in patients with hyperphosphatemia and end-stage kidney disease.

PHOSPHORUS OR PHOSPHATE?

What's in a name? That which we call a rose
By any other word would smell as sweet.
—Shakespeare, Romeo and Juliet

The terms phosphate and phosphorus are often used interchangeably, though most writers still prefer phosphate over phosphorus.

The serum concentrations of phosphate and phosphorus are the same when expressed in millimoles per liter, as every mole of phosphate contains 1 mole of phosphorus, but not the same when expressed in milligrams per deciliter.² The molecular weight of phosphorus is 30.97, whereas the molecular weight of the phosphate ion (PO₄^3–) is 94.97—more than 3 times higher. Therefore, using these terms interchangeably in this context can lead to numerical error.³

Phosphorus, being highly reactive, does not exist by itself in nature and is typically present as phosphates in biologic systems. When describing phosphorus metabolism, the term phosphates should ideally be used because phosphates are the actual participants in the bodily processes. But in the clinical laboratory, all methods that measure serum phosphorus in fact measure inorganic phosphate and are expressed in terms of milligrams of phosphorus per deciliter rather than milligrams of phosphate per deciliter, and using these 2 terms interchangeably in clinical practice should not be of concern.⁴

THE PROBLEM

US adults typically ingest 1,200 mg of phosphorus each day, and about 60% to 70% of the ingested phosphorus is absorbed both by passive paracellular diffusion via tight junctions and by active transcellular transport via sodium-phosphate cotransport. The kidneys must excrete the same amount daily to maintain a steady state. As kidney function declines, phosphorus accumulates in the blood, leading to hyperphosphatemia.

Hyperphosphatemia is often asymptomatic, but it can cause generalized itching, red eyes, and adverse effects on the bone and parathyroid glands. Higher serum phosphorus levels have been shown to be associated with vascular calcification,⁵ cardiovascular events, and higher all-cause mortality rates in the general population,⁶ in patients with diabetes,⁷ and in those with chronic kidney disease.⁸ This association between higher serum phosphorus levels and the all-cause mortality rate led to the assumption that lowering serum phosphorus levels in these patients could reduce the rates of cardiovascular events and death, and to efforts to correct hyperphosphatemia.

Research into FGF23 continues, especially its role in cardiovascular complications of chronic kidney disease, as both phosphorus and FGF23 levels are elevated in chronic kidney disease and are implicated in poor clinical outcomes in these patients. However, both FGF23 and parathyroid hormone levels rise early in the course of kidney disease, long before overt hyperphosphatemia develops. Further, FGF23 rises earlier than parathyroid hormone and has been found to be an independent risk factor for cardiovascular events and death from any cause in end-stage kidney disease.⁹

Whether hyperphosphatemia is the culprit or merely an epiphenomenon of metabolic complications of chronic kidney disease is still unclear, as more molecules are being identified in the complex process of cardiovascular calcification.¹⁰

However, one thing is clear: vascular calcification is not just a simple precipitation of calcium and phosphorus. Instead, it is an active process that involves many regulators of mineral metabolism.¹⁰ The complex nature of this process is likely one of the reasons that evidence is conflicting¹¹ about the benefits of phosphorus binders in terms of cardiovascular events or all-cause mortality in these patients.

Reducing intake

Dietary phosphorus restriction is the first step in controlling serum phosphorus. But reducing phosphorus intake while otherwise trying to optimize the nutritional status can be challenging.

The recommended daily protein intake is 1.0 to 1.2 g/kg. But phosphorus is typically found in foods rich in proteins, and restricting protein severely can compromise nutritional status and may be as bad as elevated phosphate levels in terms of outcomes.

Although plant-based foods contain more phosphate per gram of protein (ie, they have a higher ratio of phosphorus to protein) than animal-based foods, the bioavailability of phosphorus from plant foods is lower. Phosphorus in plant-based foods is mainly in the form of phytate. Humans cannot hydrolyze phytate because we lack the phytase enzyme; hence, the phosphorus in plant-based foods is not well absorbed. Therefore, a vegetarian diet may be preferable and beneficial in patients with chronic kidney disease. A small study in humans showed that a vegetarian diet resulted in lower serum phosphorus and FGF23 levels, but the study was limited by its small sample size.¹²

Patients should be advised to avoid foods that have a high phosphate content, such as processed foods, fast foods, and cola beverages, which often have phosphate-based food additives.

Further, one should be cautious about using supplements with healthy-sounding names. A case in point is “vitamin water”: 12 oz of this fruit punch-flavored beverage contains 392 mg of phosphorus,¹³ and this alone would require 12 to 15 phosphate binder tablets to bind its phosphorus content.

In addition, many prescription drugs have significant amounts of phosphorus, and this is often unrecognized.

Sherman et al¹⁴ reviewed 200 of the most commonly prescribed drugs in dialysis patients and found that 23 (11.5%) of the drug labels listed phosphorus-containing ingredients, but the actual amount of phosphorus was not listed. The phosphorus content ranged from 1.4 mg (clonidine 0.2 mg, Blue Point Laboratories, Dublin, Ireland) to 111.5 mg (paroxetine 40 mg, GlaxoSmith Kline, Philadelphia, PA). The phosphorus content was inconsistent and varied with the dose of the agent, type of formulation (tablet or syrup), branded or generic formulation, and manufacturer.

Branded lisinopril (Merck, Kenilworth, NJ) had 21.4 mg of phosphorus per 10-mg dose, while a generic product (Blue Point Laboratories, Dublin, Ireland) had 32.6 mg. Different brands of generic amlodipine 10 mg varied in their phosphorus content from 8.6 mg (Lupin Pharmaceuticals, Mumbai, India) to 27.8 mg (Greenstone LLC, Peapack, NJ) to 40.1 mg (Qualitest Pharmaceuticals, Huntsville, AL. Rena-Vite (Cypress Pharmaceuticals, Madison, MS), a multivitamin marketed to patients with kidney disease, had 37.7 mg of phosphorus per tablet. Thus, just to bind the phosphorus content of these 3 tablets (lisinopril, amlodipine, and Rena-Vite), a patient could need at least 3 to 4 extra doses of phosphate binder.

The phosphate content of medications should be considered when prescribing. For example, Reno Caps (Nnodum Pharmaceuticals, Cincinnati, OH), another vitamin supplement, has only 1.7 mg of phosphorus per tablet and should be considered, especially in patients with poorly controlled serum phosphorus levels. However, the challenge is that medication labels do not provide the phosphorus content.

Reducing phosphorus absorption

Although these agents reduce serum phosphorus and help reduce symptoms, an important quality-of-life measure, it is uncertain whether they improve clinical outcomes.¹¹ To date, no specific phosphorus binder offers a survival benefit over placebo.¹¹

Based on the limited and conflicting evidence, the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, recently updated, suggest that oral phosphorus binders should be used in patients with hyperphosphatemia to lower serum phosphorus levels toward the normal range.¹⁵ They further recommend not exceeding 1,500 mg of elemental calcium per day if a calcium-based binder is used, and they recommend avoiding calcium-based binders in patients with hypercalcemia, adynamic bone disease, or vascular calcification.

Phosphorus binders may account for up to 50% of the daily pill burden and may contribute to poor medication adherence.¹⁶ Dialysis patients need to take a lot of these drugs: by weight, 5 to 6 pounds per year.

These drugs can bind and interfere with the absorption of other vital medications and so should be taken with meals and separately from other medications.

Removing phosphorus

Removal of phosphorus by adequate dialysis or kidney transplant is the final strategy.

New agents under study

To improve phosphorus control, other agents that inhibit absorption of phosphate are being investigated.

Nicotinamide reduces expression of the sodium-phosphorus cotransporter NTP2b. Its use in combination with a low-phosphorus diet and phosphorus binders may maximize reductions in phosphorus absorption and is being studied in the CKD Optimal Management With Binders and Nicotinamide (COMBINE) study.

Tenapanor, an inhibitor of the sodium-hydrogen transporter NHE3, has been shown in animal studies to increase fecal phosphate excretion and decrease urinary phosphate excretion17 but requires further evaluation.

Phosphorus is essential for life. However, both low and high levels of phosphorus in the body have consequences, and its concentration in the blood is tightly regulated through dietary absorption, bone flux, and renal excretion and is influenced by calcitriol (1,25 hydroxyvitamin D₃), parathyroid hormone, and fibroblast growth factor 23 (FGF23).

See related articles by M. Shetty and A. Sekar

Sekar et al,¹ in this issue of the Journal, provide an extensive review of the pathophysiology of phosphorus metabolism and strategies to control phosphorus levels in patients with hyperphosphatemia and end-stage kidney disease.

PHOSPHORUS OR PHOSPHATE?

What's in a name? That which we call a rose
By any other word would smell as sweet.
—Shakespeare, Romeo and Juliet

The terms phosphate and phosphorus are often used interchangeably, though most writers still prefer phosphate over phosphorus.

The serum concentrations of phosphate and phosphorus are the same when expressed in millimoles per liter, as every mole of phosphate contains 1 mole of phosphorus, but not the same when expressed in milligrams per deciliter.² The molecular weight of phosphorus is 30.97, whereas the molecular weight of the phosphate ion (PO₄^3–) is 94.97—more than 3 times higher. Therefore, using these terms interchangeably in this context can lead to numerical error.³

Phosphorus, being highly reactive, does not exist by itself in nature and is typically present as phosphates in biologic systems. When describing phosphorus metabolism, the term phosphates should ideally be used because phosphates are the actual participants in the bodily processes. But in the clinical laboratory, all methods that measure serum phosphorus in fact measure inorganic phosphate and are expressed in terms of milligrams of phosphorus per deciliter rather than milligrams of phosphate per deciliter, and using these 2 terms interchangeably in clinical practice should not be of concern.⁴

THE PROBLEM

US adults typically ingest 1,200 mg of phosphorus each day, and about 60% to 70% of the ingested phosphorus is absorbed both by passive paracellular diffusion via tight junctions and by active transcellular transport via sodium-phosphate cotransport. The kidneys must excrete the same amount daily to maintain a steady state. As kidney function declines, phosphorus accumulates in the blood, leading to hyperphosphatemia.

Hyperphosphatemia is often asymptomatic, but it can cause generalized itching, red eyes, and adverse effects on the bone and parathyroid glands. Higher serum phosphorus levels have been shown to be associated with vascular calcification,⁵ cardiovascular events, and higher all-cause mortality rates in the general population,⁶ in patients with diabetes,⁷ and in those with chronic kidney disease.⁸ This association between higher serum phosphorus levels and the all-cause mortality rate led to the assumption that lowering serum phosphorus levels in these patients could reduce the rates of cardiovascular events and death, and to efforts to correct hyperphosphatemia.

Research into FGF23 continues, especially its role in cardiovascular complications of chronic kidney disease, as both phosphorus and FGF23 levels are elevated in chronic kidney disease and are implicated in poor clinical outcomes in these patients. However, both FGF23 and parathyroid hormone levels rise early in the course of kidney disease, long before overt hyperphosphatemia develops. Further, FGF23 rises earlier than parathyroid hormone and has been found to be an independent risk factor for cardiovascular events and death from any cause in end-stage kidney disease.⁹

Whether hyperphosphatemia is the culprit or merely an epiphenomenon of metabolic complications of chronic kidney disease is still unclear, as more molecules are being identified in the complex process of cardiovascular calcification.¹⁰

However, one thing is clear: vascular calcification is not just a simple precipitation of calcium and phosphorus. Instead, it is an active process that involves many regulators of mineral metabolism.¹⁰ The complex nature of this process is likely one of the reasons that evidence is conflicting¹¹ about the benefits of phosphorus binders in terms of cardiovascular events or all-cause mortality in these patients.

Reducing intake

Dietary phosphorus restriction is the first step in controlling serum phosphorus. But reducing phosphorus intake while otherwise trying to optimize the nutritional status can be challenging.

The recommended daily protein intake is 1.0 to 1.2 g/kg. But phosphorus is typically found in foods rich in proteins, and restricting protein severely can compromise nutritional status and may be as bad as elevated phosphate levels in terms of outcomes.

Although plant-based foods contain more phosphate per gram of protein (ie, they have a higher ratio of phosphorus to protein) than animal-based foods, the bioavailability of phosphorus from plant foods is lower. Phosphorus in plant-based foods is mainly in the form of phytate. Humans cannot hydrolyze phytate because we lack the phytase enzyme; hence, the phosphorus in plant-based foods is not well absorbed. Therefore, a vegetarian diet may be preferable and beneficial in patients with chronic kidney disease. A small study in humans showed that a vegetarian diet resulted in lower serum phosphorus and FGF23 levels, but the study was limited by its small sample size.¹²

Patients should be advised to avoid foods that have a high phosphate content, such as processed foods, fast foods, and cola beverages, which often have phosphate-based food additives.

Further, one should be cautious about using supplements with healthy-sounding names. A case in point is “vitamin water”: 12 oz of this fruit punch-flavored beverage contains 392 mg of phosphorus,¹³ and this alone would require 12 to 15 phosphate binder tablets to bind its phosphorus content.

In addition, many prescription drugs have significant amounts of phosphorus, and this is often unrecognized.

Sherman et al¹⁴ reviewed 200 of the most commonly prescribed drugs in dialysis patients and found that 23 (11.5%) of the drug labels listed phosphorus-containing ingredients, but the actual amount of phosphorus was not listed. The phosphorus content ranged from 1.4 mg (clonidine 0.2 mg, Blue Point Laboratories, Dublin, Ireland) to 111.5 mg (paroxetine 40 mg, GlaxoSmith Kline, Philadelphia, PA). The phosphorus content was inconsistent and varied with the dose of the agent, type of formulation (tablet or syrup), branded or generic formulation, and manufacturer.

Branded lisinopril (Merck, Kenilworth, NJ) had 21.4 mg of phosphorus per 10-mg dose, while a generic product (Blue Point Laboratories, Dublin, Ireland) had 32.6 mg. Different brands of generic amlodipine 10 mg varied in their phosphorus content from 8.6 mg (Lupin Pharmaceuticals, Mumbai, India) to 27.8 mg (Greenstone LLC, Peapack, NJ) to 40.1 mg (Qualitest Pharmaceuticals, Huntsville, AL. Rena-Vite (Cypress Pharmaceuticals, Madison, MS), a multivitamin marketed to patients with kidney disease, had 37.7 mg of phosphorus per tablet. Thus, just to bind the phosphorus content of these 3 tablets (lisinopril, amlodipine, and Rena-Vite), a patient could need at least 3 to 4 extra doses of phosphate binder.

The phosphate content of medications should be considered when prescribing. For example, Reno Caps (Nnodum Pharmaceuticals, Cincinnati, OH), another vitamin supplement, has only 1.7 mg of phosphorus per tablet and should be considered, especially in patients with poorly controlled serum phosphorus levels. However, the challenge is that medication labels do not provide the phosphorus content.

Reducing phosphorus absorption

Although these agents reduce serum phosphorus and help reduce symptoms, an important quality-of-life measure, it is uncertain whether they improve clinical outcomes.¹¹ To date, no specific phosphorus binder offers a survival benefit over placebo.¹¹

Based on the limited and conflicting evidence, the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, recently updated, suggest that oral phosphorus binders should be used in patients with hyperphosphatemia to lower serum phosphorus levels toward the normal range.¹⁵ They further recommend not exceeding 1,500 mg of elemental calcium per day if a calcium-based binder is used, and they recommend avoiding calcium-based binders in patients with hypercalcemia, adynamic bone disease, or vascular calcification.

Phosphorus binders may account for up to 50% of the daily pill burden and may contribute to poor medication adherence.¹⁶ Dialysis patients need to take a lot of these drugs: by weight, 5 to 6 pounds per year.

These drugs can bind and interfere with the absorption of other vital medications and so should be taken with meals and separately from other medications.

Removing phosphorus

Removal of phosphorus by adequate dialysis or kidney transplant is the final strategy.

New agents under study

To improve phosphorus control, other agents that inhibit absorption of phosphate are being investigated.

Nicotinamide reduces expression of the sodium-phosphorus cotransporter NTP2b. Its use in combination with a low-phosphorus diet and phosphorus binders may maximize reductions in phosphorus absorption and is being studied in the CKD Optimal Management With Binders and Nicotinamide (COMBINE) study.

Tenapanor, an inhibitor of the sodium-hydrogen transporter NHE3, has been shown in animal studies to increase fecal phosphate excretion and decrease urinary phosphate excretion17 but requires further evaluation.

Patients presenting with depression commonly have undiagnosed bipolar depression,^1–7 that is, depression with shifts to periods of mania. During manic or hypomanic episodes, people feel energetic, need little sleep, and are often happy and charming.⁸ But too much of a good thing can also wreak havoc on their life.

Bipolar depression (ie, depression in patients with a diagnosis of bipolar disorder) is treated differently from unipolar depression,^3,9–13 making it especially important that clinicians recognize if a patient who presents with depression has a history of (hypo)manic symptoms.

CASE 1: THE IMPULSIVE NURSE

A 32-year-old nurse presents to her primary care provider with depressed mood. She reports having had a single depressive episode when she was a college freshman. Her family history includes depression, bipolar disorder, and schizophrenia, and her paternal grandfather and a maternal aunt committed suicide. Upon questioning, she reveals that in the past, she has had 3 episodes lasting several weeks and characterized by insubordinate behavior at work, irritability, high energy, and decreased need for sleep. She regrets impulsive sexual and financial decisions that she made during these episodes and recently filed for personal bankruptcy. For the past month, her mood has been persistently low, with reduced sleep, appetite, energy, and concentration, and with passive thoughts of suicide.

A CAREFUL HISTORY IS CRITICAL

This case illustrates many typical features of bipolar depression that are revealed only by taking a thorough history. Although the patient is high-functioning, having attained a professional career, she has serious problems with sexual and financial impulsivity and at her job. She has a strong family history of mood disorder. And she describes episodes of depression and mania in the past.

Starts in young adulthood, strong heritability

Bipolar disorder can be a devastating condition with lifelong consequences,^14–20 especially as it typically starts when patients are getting an education or embarking on a career. It usually first manifests in the late teenage years and progresses in the patient’s early 20s.^21,22 The first hospitalization can occur soon thereafter.^23,24

Bipolar disorder is one of the most heritable conditions in psychiatry, and about 13% of children who have an afflicted parent develop it.²⁵ In identical twins, the concordance is about 50% to 75%, indicating the importance of genetics and environmental factors.^26,27

Associated with migraine, other conditions

The disorder is associated with a variety of conditions (Table 1).^28,29 Some conditions (eg, thyroid disease) can cause mood cycling, and some (eg, sexually transmitted infections, accidents) are the consequences of the lifestyle that may accompany mania. For unknown reasons, migraine is highly associated with bipolar disorder.

DEPRESSION AND MANIA: TWO SIDES OF THE SAME COIN

Symptoms of depression and mania are frequently viewed as opposite mood states, though many times patients report a mixture of them.^17,30–35 For both states, the features of a distinct change from the patient’s normal condition and the sustained nature of the symptoms are important diagnostically and indicate a likely underlying biological cause.

Major depressive disorder: Slowing down

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5),⁸ defines major depressive disorder as having either depressed mood or markedly diminished pleasure in most activities for most days during at least 2 weeks.

In addition, at least 4 of the following must be present during the same period:

• Appetite disturbance
• Sleep disturbance
• Motor retardation or agitation
• Lack of energy
• Feelings of worthlessness or excessive guilt
• Decreased concentration
• Recurrent thoughts of death or suicide.

An estimated 20% of the population experience a major depressive episode over their lifetime. A surprisingly high proportion of people with depression—30% to 40%—also have had subthreshold symptoms of mania (symptoms not meeting the criteria for hypomania or mania in terms of number of symptoms or duration).^21,22 Because of these odds, it is important to suspect bipolar disorder even in patients who present with depression but who may not yet have manifested episodes of mania or hypomania.

Mood disorders can be regarded as falling into a spectrum, ranging from unipolar or “pure” major depression without any features of hypomania to major depression and severe mania.^17,31–36

Mania: Speeding up

The DSM-5 defines mania as the presence of persistently elevated, expansive, or irritable mood with increased activity for more than 1 week. In addition, at least 3 of the following features must be present, with impaired functioning (4 features are required if mood is only irritable)⁸:

• Inflated self-esteem or grandiosity
• Decreased need for sleep
• Pressured speech
• Racing thoughts
• Distractibility
• Excessive involvement in pleasurable, high-risk activities.

Hypomania: No functional impairment

Hypomania is a less severe condition, in which the abnormally elevated mood is of shorter duration (4–7 days) and meets the other criteria for mania but without significant functional impairment. People may, in fact, be very functional and productive during hypomanic episodes.⁸

CLASSIFYING BIPOLAR DISORDER

Bipolar disorder is categorized according to severity.^24,37,38 The most severe form, bipolar I disorder, is marked by major depression and manic episodes. It affects up to 1.5% of the US population, with equal proportions of men and women.³⁹ Bipolar II disorder is less severe. It affects 0.8% to 1.6% of the US population, predominantly women.^21,40 In bipolar II disorder, depression is more prominent, with episodes of hypomania.

Subthreshold bipolar disorders are characterized by episodic symptoms that do not meet the threshold for depression or hypomania; the symptoms are fewer or of shorter duration. These minor types of bipolar disorder affect up to 6% of the US population.¹⁷

Other conditions within the spectrum of bipolar and depressive disorders include medication- and substance-induced mania, agitated or anxious depression, and mixed states.^31,34–36

DISTINGUISHING UNIPOLAR FROM BIPOLAR DEPRESSION

Considerable research has focused on finding a clear-cut clinical or biological feature to differentiate unipolar from bipolar depression, but so far none has been discovered. Distinguishing the two conditions still depends on clinical judgment. There are important reasons to identify the distinction between unipolar depression and bipolar disorder.

Prognosis differs. Bipolar disorder tends to be a more severe condition. Young people, who may initially present with only mild symptoms of mania, may develop serious episodes over the years. People may lose their savings, their marriage, and their career during a manic episode. The more critical the occupation (eg, doctor, pilot), the greater the potential consequences of impaired judgment brought on by even mild hypomania.^14–20

Treatment differs. Typical antidepressants given for depression can trigger a manic episode in patients with bipolar depression, with devastating consequences. Atypical neuroleptic drugs used to treat bipolar disorder can also have serious effects (eg, metabolic and neurologic effects, including irreversible tardive dyskinesia).^3,13,40–43

Despite the good reasons to do so, many doctors (including some psychiatrists) do not ask their patients about a propensity to mania or hypomania.^4–6 More stigma is attached to the diagnosis of bipolar disorder than to depression^44–47; once it is in the medical record, the patient may have problems with employment and obtaining medical insurance.^17,44 The old term “manic-depressive” is often associated in the public mind with a person on the streets displaying severely psychotic behavior; the condition is now understood to consist of a spectrum from mild to more severe illness.

Clinical indicators of bipolarity

There are many indicators that a person who presents with depression may be on the bipolar spectrum, but this is not always easily identified.^48–53

History of hypomanic symptoms or subthreshold manic symptoms. Although directly asking the patient about the defining symptoms (eg, “Have you ever had episodes of being ‘hyper’ or too happy?”) may help elicit the diagnosis, many patients with bipolar disorder only report depression, as it is psychically painful. In contrast, hypomania and even mania can be perceived as positive, as patients may have less insight into the abnormality of the condition and feel that they are functioning extremely well.

Early age of onset of a mood disorder, such as severe depression in childhood or early adulthood, points toward bipolar disorder. Diagnosing mood disorders in childhood is difficult, as children are less able to recognize or verbalize many of their symptoms.

Postpartum mood disorder, particularly with psychotic symptoms, indicates a strong possibility of a diagnosis of bipolar disorder.

Drug-induced mania, hypomania, and periods of hyperactivity are key features of bipolar disorder. If asked, patients may report feeling a “buzz” when taking an antidepressant.

Erratic patterns in work and relationships are a red flag and are viewed as “soft signs” of bipolar depression. Akiskal⁵⁴ described the “rule of three” that should make one consider bipolar disorder: for example, three failed marriages, three current jobs or frequent job changes, three distinct professions practiced at the same time, and simultaneously dating three people. Such features indicate both the hyperfunctioning and the disruptive aspects of mania.

Family history of bipolar disorder or severe psychiatric illness is a very important clue. A more subtle clue described by Akiskal⁵⁴ may be that several members of the family are very high-functioning in several different fields: eg, one may be a highly accomplished doctor, another a famous lawyer, and another a prominent politician. Or several members of the family may have erratic patterns of work and relationships. However, these subtle clues have been derived from clinical experiences and have not been validated in large-scale studies.

Dr. Z is a prominent surgical subspecialist who is part of a small group practice. His wife has become increasingly worried about his behavior changes at home, including sleeping only a few hours a night, spending sprees, and binge drinking. He reluctantly agrees to an outpatient psychiatric evaluation if she attends with him. He creates a disturbance in the waiting room by shaking everyone’s hands and trying to hug all the women. During his examination, he is loud and expansive, denying he has any problems and describing himself as “the greatest doctor in the world.” The psychiatrist recommends hospitalization, but Dr. Z refuses and becomes belligerent. He announces that he just needs a career change and that he will fly to Mexico to open a bar.

This case, from the Texas Medical Association Archives,⁵⁵ is not unusual. In addition to many characteristics discussed above, this case is typical in that the spouse brought the patient in, reflecting that the patient lacked insight that his behavior was abnormal. The disinhibition (hugging women), grandiosity, and unrealistic plans are also typical.

DIFFERENTIAL DIAGNOSIS OF BIPOLAR DEPRESSION

Anxiety disorders may be associated with dissociative speech or racing thoughts, which can be confused with bipolar illness. Personality disorders (eg, borderline, narcissistic, sociopathic) can involve a tumultuous and impulsive lifestyle resembling episodes of depression and mania. Schizoaffective illness has features of schizophrenia and bipolar disorder.

It is also possible that, despite what may look like mild features of bipolar disorder, there is no psychiatric condition. Some people with mild mania—often successful professionals or politicians—have high energy and can function very well with only a few hours of sleep. Similarly, depressive symptoms for short periods of time can be adaptive, such as in the face of a serious setback when extreme reflection and a period of inactivity can be useful, leading to subsequent reorganization.

A psychiatric diagnosis is usually made only when there is an abnormality, ie, the behavior is beyond normal limits, the person cannot control his or her symptoms, or social or occupational functioning is impaired.

SCREENING INSTRUMENTS

A few tools help determine the likelihood of bipolar disorder.

The Patient Health Questionnaire (PHQ-9)^59,60 is a good 9-item screening tool for depression.

The Mood Disorder Questionnaire⁶⁰ is specific for bipolar disorder, and like the PHQ-9, it is a patient-reported, short questionnaire that is available free online. The Mood Disorder Questionnaire asks about the symptoms of mania in a yes-no format. The result is positive if all of the following are present:

• A “yes” response to 7 of the 13 features
• Several features occur simultaneously
• The features are a moderate or serious problem.

Unlike most screening instruments, the Mood Disorder Questionnaire is more specific than sensitive. It is 93% specific for bipolar disorder in patients treated for depression in a primary care setting, but only 58% sensitive.^61–63

WHEN TO REFER TO PSYCHIATRY

Patients suspected of having bipolar disorder or who have been previously diagnosed with it should be referred to a psychiatrist if they have certain features, including:

• Bipolar I disorder
• Psychotic symptoms
• Suicide risk or in danger of harming others
• Significantly impaired functioning
• Unclear diagnosis.

CASE 3: A TELEVISION ANCHOR’S DREAM TURNS TO NIGHTMARE

According to a famous news anchor’s autobiography,⁶⁴ the steroids prescribed for her hives “revved her up.” The next course left her depressed. Antidepressant medications propelled her into a manic state, and she was soon planning a book, a television show, and a magazine all at once. During that time, she bought a cottage online. Her shyness evaporated at parties. “I was suddenly the equal of my high-energy friends who move fast and talk fast and loud,” she wrote. “I told everyone that I could understand why men felt like they could run the world, because I felt like that. This was a new me, and I liked her!”⁶⁴ She was soon diagnosed with bipolar disorder and admitted to a psychiatric clinic.

In general, acute bipolar disorder should be treated with a combination of an antidepressant and a mood stabilizer, and possibly an antipsychotic drug. An antidepressant should not be used alone, particularly with patients with a diagnosis of bipolar I disorder, because of the risk of triggering mania or the risk of faster cycling between mania and depression.¹³

Mood stabilizers include lithium, lamotrigine, and valproate. Each can prevent episodes of depression and mania. Lithium, which has been used as a mood stabilizer for 60 years, is specific for bipolar disorder, and it remains the best mood stabilizer treatment.

Antidepressants. The first-line antidepressant medication is bupropion, which is thought to be less likely to precipitate a manic episode,⁶⁵ though all antidepressants have been associated with this side effect in patients with bipolar disorder. Other antidepressants—for example, selective serotonin reuptake inhibitors such as fluoxetine and dual reuptake inhibitors such as venlafaxine and duloxetine—can also be used. The precipitation of mania and possible increased mood cycling was first described with tricylic antidepressants, so drugs of this class should be used with caution.

Neuroleptic drugs such as aripiprazole, quetiapine, and lurasidone may be the easiest drugs to use, as they have antidepressant effects and can also prevent the occurrence of mania. These medications are frequently classified as mood stabilizers. However, they may not have true mood stabilizing properties such as that of lithium. Importantly, their use tends to entail significant metabolic problems and can lead to hyperlipidemia and diabetes. In addition, Parkinson disease-like symptoms— and in some cases irreversible involuntary movements of the mouth and tongue, as well as the body (tardive dyskinesia)—are important possible side effects.

All psychiatric medications have potential side effects (Table 3). Newer antidepressants and neuroleptics may have fewer side effects than older medications but are not more effective.

Should milder forms of bipolar depression be treated?

A dilemma is whether we should treat milder forms of bipolar depression, such as bipolar II depression, depression with subthreshold hypomania symptoms, or depression in persons with a strong family history of bipolar disorder.

Many doctors are justifiably reluctant to prescribe antidepressants for depression because of the risk of triggering mania. Although mood stabilizers such as lithium would counteract possible mania emergence, physicians often do not prescribe them because of inexperience and fear of risks and possible side effects. Patients are likewise resistant because they feel that use of mood stabilizers is tantamount to being told they are “manic-depressive,” with its associated stigma.

Overuse of atypical neuroleptics such as aripiprazole, quetiapine, and olanzapine has led to an awareness of metabolic syndrome and tardive dyskinesia, also making doctors cautious about using these drugs.

Answer: Yes, but treat with caution

Not treating depression consigns a patient to suffer with untreated depression, sometimes for years. Outcomes for patients with depression and bipolar disorder are often poor because the conditions are not recognized, and even when the conditions are recognized, doctors and patients may be reluctant to medicate appropriately. Medications should be used as needed to treat depression, but with an awareness of the possible side effects and with close patient monitoring.

A truly sustained manic state (unlike the brief euphoria brought on by some drugs) is not actually so easy to induce. In an unpublished Cleveland Clinic study, we monitored peaks of hypomanic symptoms in young patients (ages 15–30) during antidepressant treatment without mood stabilizers. About 30% to 40% of patients had subthreshold manic symptoms or a family history of bipolar disorder; 3 patients out of 51 developed hypomania leading to a change of diagnosis to bipolar disorder. Even in patients who had no risk factors for bipolar disorder, 2 out of 53 converted to a bipolar diagnosis. So conversion rates in patients with subthreshold bipolar disorder seem to be low, and the disorder can be identified early by monitoring the patient closely.

NONPHARMACOLOGIC TREATMENTS FOR DEPRESSION

Psychotherapy is indicated for all patients on medications for depression, as both pharmacologic and nonpharmacologic treatments are more effective when combined.⁶⁶ Other treatments include trans­cranial magnetic stimulation, electroconvulsive therapy, light therapy, and exercise. Having a consistent daily routine, particularly regarding the sleep-wake schedule, is also helpful, and patients should be educated about its importance.

Patients presenting with depression commonly have undiagnosed bipolar depression,^1–7 that is, depression with shifts to periods of mania. During manic or hypomanic episodes, people feel energetic, need little sleep, and are often happy and charming.⁸ But too much of a good thing can also wreak havoc on their life.

Bipolar depression (ie, depression in patients with a diagnosis of bipolar disorder) is treated differently from unipolar depression,^3,9–13 making it especially important that clinicians recognize if a patient who presents with depression has a history of (hypo)manic symptoms.

CASE 1: THE IMPULSIVE NURSE

A 32-year-old nurse presents to her primary care provider with depressed mood. She reports having had a single depressive episode when she was a college freshman. Her family history includes depression, bipolar disorder, and schizophrenia, and her paternal grandfather and a maternal aunt committed suicide. Upon questioning, she reveals that in the past, she has had 3 episodes lasting several weeks and characterized by insubordinate behavior at work, irritability, high energy, and decreased need for sleep. She regrets impulsive sexual and financial decisions that she made during these episodes and recently filed for personal bankruptcy. For the past month, her mood has been persistently low, with reduced sleep, appetite, energy, and concentration, and with passive thoughts of suicide.

A CAREFUL HISTORY IS CRITICAL

This case illustrates many typical features of bipolar depression that are revealed only by taking a thorough history. Although the patient is high-functioning, having attained a professional career, she has serious problems with sexual and financial impulsivity and at her job. She has a strong family history of mood disorder. And she describes episodes of depression and mania in the past.

Starts in young adulthood, strong heritability

Bipolar disorder can be a devastating condition with lifelong consequences,^14–20 especially as it typically starts when patients are getting an education or embarking on a career. It usually first manifests in the late teenage years and progresses in the patient’s early 20s.^21,22 The first hospitalization can occur soon thereafter.^23,24

Bipolar disorder is one of the most heritable conditions in psychiatry, and about 13% of children who have an afflicted parent develop it.²⁵ In identical twins, the concordance is about 50% to 75%, indicating the importance of genetics and environmental factors.^26,27

Associated with migraine, other conditions

The disorder is associated with a variety of conditions (Table 1).^28,29 Some conditions (eg, thyroid disease) can cause mood cycling, and some (eg, sexually transmitted infections, accidents) are the consequences of the lifestyle that may accompany mania. For unknown reasons, migraine is highly associated with bipolar disorder.

DEPRESSION AND MANIA: TWO SIDES OF THE SAME COIN

Symptoms of depression and mania are frequently viewed as opposite mood states, though many times patients report a mixture of them.^17,30–35 For both states, the features of a distinct change from the patient’s normal condition and the sustained nature of the symptoms are important diagnostically and indicate a likely underlying biological cause.

Major depressive disorder: Slowing down

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5),⁸ defines major depressive disorder as having either depressed mood or markedly diminished pleasure in most activities for most days during at least 2 weeks.

In addition, at least 4 of the following must be present during the same period:

• Appetite disturbance
• Sleep disturbance
• Motor retardation or agitation
• Lack of energy
• Feelings of worthlessness or excessive guilt
• Decreased concentration
• Recurrent thoughts of death or suicide.

An estimated 20% of the population experience a major depressive episode over their lifetime. A surprisingly high proportion of people with depression—30% to 40%—also have had subthreshold symptoms of mania (symptoms not meeting the criteria for hypomania or mania in terms of number of symptoms or duration).^21,22 Because of these odds, it is important to suspect bipolar disorder even in patients who present with depression but who may not yet have manifested episodes of mania or hypomania.

Mood disorders can be regarded as falling into a spectrum, ranging from unipolar or “pure” major depression without any features of hypomania to major depression and severe mania.^17,31–36

Mania: Speeding up

The DSM-5 defines mania as the presence of persistently elevated, expansive, or irritable mood with increased activity for more than 1 week. In addition, at least 3 of the following features must be present, with impaired functioning (4 features are required if mood is only irritable)⁸:

• Inflated self-esteem or grandiosity
• Decreased need for sleep
• Pressured speech
• Racing thoughts
• Distractibility
• Excessive involvement in pleasurable, high-risk activities.

Hypomania: No functional impairment

Hypomania is a less severe condition, in which the abnormally elevated mood is of shorter duration (4–7 days) and meets the other criteria for mania but without significant functional impairment. People may, in fact, be very functional and productive during hypomanic episodes.⁸

CLASSIFYING BIPOLAR DISORDER

Bipolar disorder is categorized according to severity.^24,37,38 The most severe form, bipolar I disorder, is marked by major depression and manic episodes. It affects up to 1.5% of the US population, with equal proportions of men and women.³⁹ Bipolar II disorder is less severe. It affects 0.8% to 1.6% of the US population, predominantly women.^21,40 In bipolar II disorder, depression is more prominent, with episodes of hypomania.

Subthreshold bipolar disorders are characterized by episodic symptoms that do not meet the threshold for depression or hypomania; the symptoms are fewer or of shorter duration. These minor types of bipolar disorder affect up to 6% of the US population.¹⁷

Other conditions within the spectrum of bipolar and depressive disorders include medication- and substance-induced mania, agitated or anxious depression, and mixed states.^31,34–36

DISTINGUISHING UNIPOLAR FROM BIPOLAR DEPRESSION

Considerable research has focused on finding a clear-cut clinical or biological feature to differentiate unipolar from bipolar depression, but so far none has been discovered. Distinguishing the two conditions still depends on clinical judgment. There are important reasons to identify the distinction between unipolar depression and bipolar disorder.

Prognosis differs. Bipolar disorder tends to be a more severe condition. Young people, who may initially present with only mild symptoms of mania, may develop serious episodes over the years. People may lose their savings, their marriage, and their career during a manic episode. The more critical the occupation (eg, doctor, pilot), the greater the potential consequences of impaired judgment brought on by even mild hypomania.^14–20

Treatment differs. Typical antidepressants given for depression can trigger a manic episode in patients with bipolar depression, with devastating consequences. Atypical neuroleptic drugs used to treat bipolar disorder can also have serious effects (eg, metabolic and neurologic effects, including irreversible tardive dyskinesia).^3,13,40–43

Despite the good reasons to do so, many doctors (including some psychiatrists) do not ask their patients about a propensity to mania or hypomania.^4–6 More stigma is attached to the diagnosis of bipolar disorder than to depression^44–47; once it is in the medical record, the patient may have problems with employment and obtaining medical insurance.^17,44 The old term “manic-depressive” is often associated in the public mind with a person on the streets displaying severely psychotic behavior; the condition is now understood to consist of a spectrum from mild to more severe illness.

Clinical indicators of bipolarity

There are many indicators that a person who presents with depression may be on the bipolar spectrum, but this is not always easily identified.^48–53

History of hypomanic symptoms or subthreshold manic symptoms. Although directly asking the patient about the defining symptoms (eg, “Have you ever had episodes of being ‘hyper’ or too happy?”) may help elicit the diagnosis, many patients with bipolar disorder only report depression, as it is psychically painful. In contrast, hypomania and even mania can be perceived as positive, as patients may have less insight into the abnormality of the condition and feel that they are functioning extremely well.

Early age of onset of a mood disorder, such as severe depression in childhood or early adulthood, points toward bipolar disorder. Diagnosing mood disorders in childhood is difficult, as children are less able to recognize or verbalize many of their symptoms.

Postpartum mood disorder, particularly with psychotic symptoms, indicates a strong possibility of a diagnosis of bipolar disorder.

Drug-induced mania, hypomania, and periods of hyperactivity are key features of bipolar disorder. If asked, patients may report feeling a “buzz” when taking an antidepressant.

Erratic patterns in work and relationships are a red flag and are viewed as “soft signs” of bipolar depression. Akiskal⁵⁴ described the “rule of three” that should make one consider bipolar disorder: for example, three failed marriages, three current jobs or frequent job changes, three distinct professions practiced at the same time, and simultaneously dating three people. Such features indicate both the hyperfunctioning and the disruptive aspects of mania.

Family history of bipolar disorder or severe psychiatric illness is a very important clue. A more subtle clue described by Akiskal⁵⁴ may be that several members of the family are very high-functioning in several different fields: eg, one may be a highly accomplished doctor, another a famous lawyer, and another a prominent politician. Or several members of the family may have erratic patterns of work and relationships. However, these subtle clues have been derived from clinical experiences and have not been validated in large-scale studies.

Dr. Z is a prominent surgical subspecialist who is part of a small group practice. His wife has become increasingly worried about his behavior changes at home, including sleeping only a few hours a night, spending sprees, and binge drinking. He reluctantly agrees to an outpatient psychiatric evaluation if she attends with him. He creates a disturbance in the waiting room by shaking everyone’s hands and trying to hug all the women. During his examination, he is loud and expansive, denying he has any problems and describing himself as “the greatest doctor in the world.” The psychiatrist recommends hospitalization, but Dr. Z refuses and becomes belligerent. He announces that he just needs a career change and that he will fly to Mexico to open a bar.

This case, from the Texas Medical Association Archives,⁵⁵ is not unusual. In addition to many characteristics discussed above, this case is typical in that the spouse brought the patient in, reflecting that the patient lacked insight that his behavior was abnormal. The disinhibition (hugging women), grandiosity, and unrealistic plans are also typical.

DIFFERENTIAL DIAGNOSIS OF BIPOLAR DEPRESSION

Anxiety disorders may be associated with dissociative speech or racing thoughts, which can be confused with bipolar illness. Personality disorders (eg, borderline, narcissistic, sociopathic) can involve a tumultuous and impulsive lifestyle resembling episodes of depression and mania. Schizoaffective illness has features of schizophrenia and bipolar disorder.

It is also possible that, despite what may look like mild features of bipolar disorder, there is no psychiatric condition. Some people with mild mania—often successful professionals or politicians—have high energy and can function very well with only a few hours of sleep. Similarly, depressive symptoms for short periods of time can be adaptive, such as in the face of a serious setback when extreme reflection and a period of inactivity can be useful, leading to subsequent reorganization.

A psychiatric diagnosis is usually made only when there is an abnormality, ie, the behavior is beyond normal limits, the person cannot control his or her symptoms, or social or occupational functioning is impaired.

SCREENING INSTRUMENTS

A few tools help determine the likelihood of bipolar disorder.

The Patient Health Questionnaire (PHQ-9)^59,60 is a good 9-item screening tool for depression.

The Mood Disorder Questionnaire⁶⁰ is specific for bipolar disorder, and like the PHQ-9, it is a patient-reported, short questionnaire that is available free online. The Mood Disorder Questionnaire asks about the symptoms of mania in a yes-no format. The result is positive if all of the following are present:

• A “yes” response to 7 of the 13 features
• Several features occur simultaneously
• The features are a moderate or serious problem.

Unlike most screening instruments, the Mood Disorder Questionnaire is more specific than sensitive. It is 93% specific for bipolar disorder in patients treated for depression in a primary care setting, but only 58% sensitive.^61–63

WHEN TO REFER TO PSYCHIATRY

Patients suspected of having bipolar disorder or who have been previously diagnosed with it should be referred to a psychiatrist if they have certain features, including:

• Bipolar I disorder
• Psychotic symptoms
• Suicide risk or in danger of harming others
• Significantly impaired functioning
• Unclear diagnosis.

CASE 3: A TELEVISION ANCHOR’S DREAM TURNS TO NIGHTMARE

According to a famous news anchor’s autobiography,⁶⁴ the steroids prescribed for her hives “revved her up.” The next course left her depressed. Antidepressant medications propelled her into a manic state, and she was soon planning a book, a television show, and a magazine all at once. During that time, she bought a cottage online. Her shyness evaporated at parties. “I was suddenly the equal of my high-energy friends who move fast and talk fast and loud,” she wrote. “I told everyone that I could understand why men felt like they could run the world, because I felt like that. This was a new me, and I liked her!”⁶⁴ She was soon diagnosed with bipolar disorder and admitted to a psychiatric clinic.

In general, acute bipolar disorder should be treated with a combination of an antidepressant and a mood stabilizer, and possibly an antipsychotic drug. An antidepressant should not be used alone, particularly with patients with a diagnosis of bipolar I disorder, because of the risk of triggering mania or the risk of faster cycling between mania and depression.¹³

Mood stabilizers include lithium, lamotrigine, and valproate. Each can prevent episodes of depression and mania. Lithium, which has been used as a mood stabilizer for 60 years, is specific for bipolar disorder, and it remains the best mood stabilizer treatment.

Antidepressants. The first-line antidepressant medication is bupropion, which is thought to be less likely to precipitate a manic episode,⁶⁵ though all antidepressants have been associated with this side effect in patients with bipolar disorder. Other antidepressants—for example, selective serotonin reuptake inhibitors such as fluoxetine and dual reuptake inhibitors such as venlafaxine and duloxetine—can also be used. The precipitation of mania and possible increased mood cycling was first described with tricylic antidepressants, so drugs of this class should be used with caution.

Neuroleptic drugs such as aripiprazole, quetiapine, and lurasidone may be the easiest drugs to use, as they have antidepressant effects and can also prevent the occurrence of mania. These medications are frequently classified as mood stabilizers. However, they may not have true mood stabilizing properties such as that of lithium. Importantly, their use tends to entail significant metabolic problems and can lead to hyperlipidemia and diabetes. In addition, Parkinson disease-like symptoms— and in some cases irreversible involuntary movements of the mouth and tongue, as well as the body (tardive dyskinesia)—are important possible side effects.

All psychiatric medications have potential side effects (Table 3). Newer antidepressants and neuroleptics may have fewer side effects than older medications but are not more effective.

Should milder forms of bipolar depression be treated?

A dilemma is whether we should treat milder forms of bipolar depression, such as bipolar II depression, depression with subthreshold hypomania symptoms, or depression in persons with a strong family history of bipolar disorder.

Many doctors are justifiably reluctant to prescribe antidepressants for depression because of the risk of triggering mania. Although mood stabilizers such as lithium would counteract possible mania emergence, physicians often do not prescribe them because of inexperience and fear of risks and possible side effects. Patients are likewise resistant because they feel that use of mood stabilizers is tantamount to being told they are “manic-depressive,” with its associated stigma.

Overuse of atypical neuroleptics such as aripiprazole, quetiapine, and olanzapine has led to an awareness of metabolic syndrome and tardive dyskinesia, also making doctors cautious about using these drugs.

Answer: Yes, but treat with caution

Not treating depression consigns a patient to suffer with untreated depression, sometimes for years. Outcomes for patients with depression and bipolar disorder are often poor because the conditions are not recognized, and even when the conditions are recognized, doctors and patients may be reluctant to medicate appropriately. Medications should be used as needed to treat depression, but with an awareness of the possible side effects and with close patient monitoring.

A truly sustained manic state (unlike the brief euphoria brought on by some drugs) is not actually so easy to induce. In an unpublished Cleveland Clinic study, we monitored peaks of hypomanic symptoms in young patients (ages 15–30) during antidepressant treatment without mood stabilizers. About 30% to 40% of patients had subthreshold manic symptoms or a family history of bipolar disorder; 3 patients out of 51 developed hypomania leading to a change of diagnosis to bipolar disorder. Even in patients who had no risk factors for bipolar disorder, 2 out of 53 converted to a bipolar diagnosis. So conversion rates in patients with subthreshold bipolar disorder seem to be low, and the disorder can be identified early by monitoring the patient closely.

NONPHARMACOLOGIC TREATMENTS FOR DEPRESSION

Psychotherapy is indicated for all patients on medications for depression, as both pharmacologic and nonpharmacologic treatments are more effective when combined.⁶⁶ Other treatments include trans­cranial magnetic stimulation, electroconvulsive therapy, light therapy, and exercise. Having a consistent daily routine, particularly regarding the sleep-wake schedule, is also helpful, and patients should be educated about its importance.

Patients presenting with depression commonly have undiagnosed bipolar depression,^1–7 that is, depression with shifts to periods of mania. During manic or hypomanic episodes, people feel energetic, need little sleep, and are often happy and charming.⁸ But too much of a good thing can also wreak havoc on their life.

Bipolar depression (ie, depression in patients with a diagnosis of bipolar disorder) is treated differently from unipolar depression,^3,9–13 making it especially important that clinicians recognize if a patient who presents with depression has a history of (hypo)manic symptoms.

CASE 1: THE IMPULSIVE NURSE

A 32-year-old nurse presents to her primary care provider with depressed mood. She reports having had a single depressive episode when she was a college freshman. Her family history includes depression, bipolar disorder, and schizophrenia, and her paternal grandfather and a maternal aunt committed suicide. Upon questioning, she reveals that in the past, she has had 3 episodes lasting several weeks and characterized by insubordinate behavior at work, irritability, high energy, and decreased need for sleep. She regrets impulsive sexual and financial decisions that she made during these episodes and recently filed for personal bankruptcy. For the past month, her mood has been persistently low, with reduced sleep, appetite, energy, and concentration, and with passive thoughts of suicide.

A CAREFUL HISTORY IS CRITICAL

This case illustrates many typical features of bipolar depression that are revealed only by taking a thorough history. Although the patient is high-functioning, having attained a professional career, she has serious problems with sexual and financial impulsivity and at her job. She has a strong family history of mood disorder. And she describes episodes of depression and mania in the past.

Starts in young adulthood, strong heritability

Bipolar disorder can be a devastating condition with lifelong consequences,^14–20 especially as it typically starts when patients are getting an education or embarking on a career. It usually first manifests in the late teenage years and progresses in the patient’s early 20s.^21,22 The first hospitalization can occur soon thereafter.^23,24

Bipolar disorder is one of the most heritable conditions in psychiatry, and about 13% of children who have an afflicted parent develop it.²⁵ In identical twins, the concordance is about 50% to 75%, indicating the importance of genetics and environmental factors.^26,27

Associated with migraine, other conditions

The disorder is associated with a variety of conditions (Table 1).^28,29 Some conditions (eg, thyroid disease) can cause mood cycling, and some (eg, sexually transmitted infections, accidents) are the consequences of the lifestyle that may accompany mania. For unknown reasons, migraine is highly associated with bipolar disorder.

DEPRESSION AND MANIA: TWO SIDES OF THE SAME COIN

Symptoms of depression and mania are frequently viewed as opposite mood states, though many times patients report a mixture of them.^17,30–35 For both states, the features of a distinct change from the patient’s normal condition and the sustained nature of the symptoms are important diagnostically and indicate a likely underlying biological cause.

Major depressive disorder: Slowing down

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5),⁸ defines major depressive disorder as having either depressed mood or markedly diminished pleasure in most activities for most days during at least 2 weeks.

In addition, at least 4 of the following must be present during the same period:

• Appetite disturbance
• Sleep disturbance
• Motor retardation or agitation
• Lack of energy
• Feelings of worthlessness or excessive guilt
• Decreased concentration
• Recurrent thoughts of death or suicide.

An estimated 20% of the population experience a major depressive episode over their lifetime. A surprisingly high proportion of people with depression—30% to 40%—also have had subthreshold symptoms of mania (symptoms not meeting the criteria for hypomania or mania in terms of number of symptoms or duration).^21,22 Because of these odds, it is important to suspect bipolar disorder even in patients who present with depression but who may not yet have manifested episodes of mania or hypomania.

Mood disorders can be regarded as falling into a spectrum, ranging from unipolar or “pure” major depression without any features of hypomania to major depression and severe mania.^17,31–36

Mania: Speeding up

The DSM-5 defines mania as the presence of persistently elevated, expansive, or irritable mood with increased activity for more than 1 week. In addition, at least 3 of the following features must be present, with impaired functioning (4 features are required if mood is only irritable)⁸:

• Inflated self-esteem or grandiosity
• Decreased need for sleep
• Pressured speech
• Racing thoughts
• Distractibility
• Excessive involvement in pleasurable, high-risk activities.

Hypomania: No functional impairment

Hypomania is a less severe condition, in which the abnormally elevated mood is of shorter duration (4–7 days) and meets the other criteria for mania but without significant functional impairment. People may, in fact, be very functional and productive during hypomanic episodes.⁸

CLASSIFYING BIPOLAR DISORDER

Bipolar disorder is categorized according to severity.^24,37,38 The most severe form, bipolar I disorder, is marked by major depression and manic episodes. It affects up to 1.5% of the US population, with equal proportions of men and women.³⁹ Bipolar II disorder is less severe. It affects 0.8% to 1.6% of the US population, predominantly women.^21,40 In bipolar II disorder, depression is more prominent, with episodes of hypomania.

Subthreshold bipolar disorders are characterized by episodic symptoms that do not meet the threshold for depression or hypomania; the symptoms are fewer or of shorter duration. These minor types of bipolar disorder affect up to 6% of the US population.¹⁷

Other conditions within the spectrum of bipolar and depressive disorders include medication- and substance-induced mania, agitated or anxious depression, and mixed states.^31,34–36

DISTINGUISHING UNIPOLAR FROM BIPOLAR DEPRESSION

Considerable research has focused on finding a clear-cut clinical or biological feature to differentiate unipolar from bipolar depression, but so far none has been discovered. Distinguishing the two conditions still depends on clinical judgment. There are important reasons to identify the distinction between unipolar depression and bipolar disorder.

Prognosis differs. Bipolar disorder tends to be a more severe condition. Young people, who may initially present with only mild symptoms of mania, may develop serious episodes over the years. People may lose their savings, their marriage, and their career during a manic episode. The more critical the occupation (eg, doctor, pilot), the greater the potential consequences of impaired judgment brought on by even mild hypomania.^14–20

Treatment differs. Typical antidepressants given for depression can trigger a manic episode in patients with bipolar depression, with devastating consequences. Atypical neuroleptic drugs used to treat bipolar disorder can also have serious effects (eg, metabolic and neurologic effects, including irreversible tardive dyskinesia).^3,13,40–43

Despite the good reasons to do so, many doctors (including some psychiatrists) do not ask their patients about a propensity to mania or hypomania.^4–6 More stigma is attached to the diagnosis of bipolar disorder than to depression^44–47; once it is in the medical record, the patient may have problems with employment and obtaining medical insurance.^17,44 The old term “manic-depressive” is often associated in the public mind with a person on the streets displaying severely psychotic behavior; the condition is now understood to consist of a spectrum from mild to more severe illness.

Clinical indicators of bipolarity

There are many indicators that a person who presents with depression may be on the bipolar spectrum, but this is not always easily identified.^48–53

History of hypomanic symptoms or subthreshold manic symptoms. Although directly asking the patient about the defining symptoms (eg, “Have you ever had episodes of being ‘hyper’ or too happy?”) may help elicit the diagnosis, many patients with bipolar disorder only report depression, as it is psychically painful. In contrast, hypomania and even mania can be perceived as positive, as patients may have less insight into the abnormality of the condition and feel that they are functioning extremely well.

Early age of onset of a mood disorder, such as severe depression in childhood or early adulthood, points toward bipolar disorder. Diagnosing mood disorders in childhood is difficult, as children are less able to recognize or verbalize many of their symptoms.

Postpartum mood disorder, particularly with psychotic symptoms, indicates a strong possibility of a diagnosis of bipolar disorder.

Drug-induced mania, hypomania, and periods of hyperactivity are key features of bipolar disorder. If asked, patients may report feeling a “buzz” when taking an antidepressant.

Erratic patterns in work and relationships are a red flag and are viewed as “soft signs” of bipolar depression. Akiskal⁵⁴ described the “rule of three” that should make one consider bipolar disorder: for example, three failed marriages, three current jobs or frequent job changes, three distinct professions practiced at the same time, and simultaneously dating three people. Such features indicate both the hyperfunctioning and the disruptive aspects of mania.

Family history of bipolar disorder or severe psychiatric illness is a very important clue. A more subtle clue described by Akiskal⁵⁴ may be that several members of the family are very high-functioning in several different fields: eg, one may be a highly accomplished doctor, another a famous lawyer, and another a prominent politician. Or several members of the family may have erratic patterns of work and relationships. However, these subtle clues have been derived from clinical experiences and have not been validated in large-scale studies.

Dr. Z is a prominent surgical subspecialist who is part of a small group practice. His wife has become increasingly worried about his behavior changes at home, including sleeping only a few hours a night, spending sprees, and binge drinking. He reluctantly agrees to an outpatient psychiatric evaluation if she attends with him. He creates a disturbance in the waiting room by shaking everyone’s hands and trying to hug all the women. During his examination, he is loud and expansive, denying he has any problems and describing himself as “the greatest doctor in the world.” The psychiatrist recommends hospitalization, but Dr. Z refuses and becomes belligerent. He announces that he just needs a career change and that he will fly to Mexico to open a bar.

This case, from the Texas Medical Association Archives,⁵⁵ is not unusual. In addition to many characteristics discussed above, this case is typical in that the spouse brought the patient in, reflecting that the patient lacked insight that his behavior was abnormal. The disinhibition (hugging women), grandiosity, and unrealistic plans are also typical.

DIFFERENTIAL DIAGNOSIS OF BIPOLAR DEPRESSION

Anxiety disorders may be associated with dissociative speech or racing thoughts, which can be confused with bipolar illness. Personality disorders (eg, borderline, narcissistic, sociopathic) can involve a tumultuous and impulsive lifestyle resembling episodes of depression and mania. Schizoaffective illness has features of schizophrenia and bipolar disorder.

It is also possible that, despite what may look like mild features of bipolar disorder, there is no psychiatric condition. Some people with mild mania—often successful professionals or politicians—have high energy and can function very well with only a few hours of sleep. Similarly, depressive symptoms for short periods of time can be adaptive, such as in the face of a serious setback when extreme reflection and a period of inactivity can be useful, leading to subsequent reorganization.

A psychiatric diagnosis is usually made only when there is an abnormality, ie, the behavior is beyond normal limits, the person cannot control his or her symptoms, or social or occupational functioning is impaired.

SCREENING INSTRUMENTS

A few tools help determine the likelihood of bipolar disorder.

The Patient Health Questionnaire (PHQ-9)^59,60 is a good 9-item screening tool for depression.

The Mood Disorder Questionnaire⁶⁰ is specific for bipolar disorder, and like the PHQ-9, it is a patient-reported, short questionnaire that is available free online. The Mood Disorder Questionnaire asks about the symptoms of mania in a yes-no format. The result is positive if all of the following are present:

• A “yes” response to 7 of the 13 features
• Several features occur simultaneously
• The features are a moderate or serious problem.

Unlike most screening instruments, the Mood Disorder Questionnaire is more specific than sensitive. It is 93% specific for bipolar disorder in patients treated for depression in a primary care setting, but only 58% sensitive.^61–63

WHEN TO REFER TO PSYCHIATRY

Patients suspected of having bipolar disorder or who have been previously diagnosed with it should be referred to a psychiatrist if they have certain features, including:

• Bipolar I disorder
• Psychotic symptoms
• Suicide risk or in danger of harming others
• Significantly impaired functioning
• Unclear diagnosis.

CASE 3: A TELEVISION ANCHOR’S DREAM TURNS TO NIGHTMARE

According to a famous news anchor’s autobiography,⁶⁴ the steroids prescribed for her hives “revved her up.” The next course left her depressed. Antidepressant medications propelled her into a manic state, and she was soon planning a book, a television show, and a magazine all at once. During that time, she bought a cottage online. Her shyness evaporated at parties. “I was suddenly the equal of my high-energy friends who move fast and talk fast and loud,” she wrote. “I told everyone that I could understand why men felt like they could run the world, because I felt like that. This was a new me, and I liked her!”⁶⁴ She was soon diagnosed with bipolar disorder and admitted to a psychiatric clinic.

In general, acute bipolar disorder should be treated with a combination of an antidepressant and a mood stabilizer, and possibly an antipsychotic drug. An antidepressant should not be used alone, particularly with patients with a diagnosis of bipolar I disorder, because of the risk of triggering mania or the risk of faster cycling between mania and depression.¹³

Mood stabilizers include lithium, lamotrigine, and valproate. Each can prevent episodes of depression and mania. Lithium, which has been used as a mood stabilizer for 60 years, is specific for bipolar disorder, and it remains the best mood stabilizer treatment.

Antidepressants. The first-line antidepressant medication is bupropion, which is thought to be less likely to precipitate a manic episode,⁶⁵ though all antidepressants have been associated with this side effect in patients with bipolar disorder. Other antidepressants—for example, selective serotonin reuptake inhibitors such as fluoxetine and dual reuptake inhibitors such as venlafaxine and duloxetine—can also be used. The precipitation of mania and possible increased mood cycling was first described with tricylic antidepressants, so drugs of this class should be used with caution.

Neuroleptic drugs such as aripiprazole, quetiapine, and lurasidone may be the easiest drugs to use, as they have antidepressant effects and can also prevent the occurrence of mania. These medications are frequently classified as mood stabilizers. However, they may not have true mood stabilizing properties such as that of lithium. Importantly, their use tends to entail significant metabolic problems and can lead to hyperlipidemia and diabetes. In addition, Parkinson disease-like symptoms— and in some cases irreversible involuntary movements of the mouth and tongue, as well as the body (tardive dyskinesia)—are important possible side effects.

All psychiatric medications have potential side effects (Table 3). Newer antidepressants and neuroleptics may have fewer side effects than older medications but are not more effective.

Should milder forms of bipolar depression be treated?

A dilemma is whether we should treat milder forms of bipolar depression, such as bipolar II depression, depression with subthreshold hypomania symptoms, or depression in persons with a strong family history of bipolar disorder.

Many doctors are justifiably reluctant to prescribe antidepressants for depression because of the risk of triggering mania. Although mood stabilizers such as lithium would counteract possible mania emergence, physicians often do not prescribe them because of inexperience and fear of risks and possible side effects. Patients are likewise resistant because they feel that use of mood stabilizers is tantamount to being told they are “manic-depressive,” with its associated stigma.

Overuse of atypical neuroleptics such as aripiprazole, quetiapine, and olanzapine has led to an awareness of metabolic syndrome and tardive dyskinesia, also making doctors cautious about using these drugs.

Answer: Yes, but treat with caution

Not treating depression consigns a patient to suffer with untreated depression, sometimes for years. Outcomes for patients with depression and bipolar disorder are often poor because the conditions are not recognized, and even when the conditions are recognized, doctors and patients may be reluctant to medicate appropriately. Medications should be used as needed to treat depression, but with an awareness of the possible side effects and with close patient monitoring.

A truly sustained manic state (unlike the brief euphoria brought on by some drugs) is not actually so easy to induce. In an unpublished Cleveland Clinic study, we monitored peaks of hypomanic symptoms in young patients (ages 15–30) during antidepressant treatment without mood stabilizers. About 30% to 40% of patients had subthreshold manic symptoms or a family history of bipolar disorder; 3 patients out of 51 developed hypomania leading to a change of diagnosis to bipolar disorder. Even in patients who had no risk factors for bipolar disorder, 2 out of 53 converted to a bipolar diagnosis. So conversion rates in patients with subthreshold bipolar disorder seem to be low, and the disorder can be identified early by monitoring the patient closely.

NONPHARMACOLOGIC TREATMENTS FOR DEPRESSION

Psychotherapy is indicated for all patients on medications for depression, as both pharmacologic and nonpharmacologic treatments are more effective when combined.⁶⁶ Other treatments include trans­cranial magnetic stimulation, electroconvulsive therapy, light therapy, and exercise. Having a consistent daily routine, particularly regarding the sleep-wake schedule, is also helpful, and patients should be educated about its importance.

NEW ORLEANS – Physicians committed to fighting the national opioid epidemic really need to take the 8-hour training course on addiction treatment required to obtain a Drug Enforcement Administration ‘X’ number, because it will enable them to prescribe buprenorphine, a drug with unique advantages for many affected patients, Ellie Grossman, MD, asserted at the annual meeting of the American College of Physicians.

Bruce Jancin/MDedge News

Buprenorphine (Subutex) is one of the three medications approved for treatment of opioid use disorder (OUD), along with methadone and naltrexone (Revia). And for certain patients, it’s clearly the best choice, according to Dr. Grossman, a general internist at Harvard Medical School, Boston, and the primary care lead for behavioral health integration at the Cambridge (Mass.) Health Alliance.

The DEA X number certification process, which entails obtaining a waiver through SAMHSA – the Substance Abuse and Mental Health Services Administration – is bureaucratic. It’s unpopular with many physicians. But it’s well worth 8 hours of an internist’s time to get the waiver and gain the ability to prescribe buprenorphine.

“The requirement is admittedly clunky, and many people have strong feelings about whether this is a regulation that should exist,” according to Dr. Grossman. “I myself didn’t need to have special training to prescribe methadone, a full opioid agonist that my patients could easily die from. But I did have to undergo an 8-hour training to prescribe buprenorphine, and it’s much harder to die from that drug.”

She addressed which of the three medications for OUD is the best fit in a given patient, the appropriate treatment duration, and the role of adjunctive counseling, which – spoiler alert – has been cast into question by the results of a major government-funded randomized trial.

Dr. Grossman’s overriding message: “You are saving lives by getting people on medication.”

Indeed, studies have shown that patients with OUD who receive no treatment have a sixfold increase in the standardized mortality ratio, compared with the general population. Contrast that with the less than 2-fold increased risk with medication-assisted treatment and roughly a 2.5-fold increased risk when medication is given short term to cover withdrawal and then tapered and discontinued.

Other documented benefits of long-term medication-assisted treatment of patients with OUD as described in a 2014 Cochrane review include reductions in injection drug use, crime days, HIV-related risk behaviors and seroconversion, and improved health and social functioning.

Of note, those well-documented benefits apply only to methadone, a full opioid agonist, and buprenorphine, a partial agonist, because those two drugs have been around long enough to generate long-term outcome data. Naltrexone, which has a completely different mechanism of action – it’s a full opioid antagonist – has not as of yet.
 

Individualizing medical therapy for OUD

Physicians can’t write a prescription for methadone. The drug must be administered at a certified opioid treatment program, or OTP, otherwise known as a methadone clinic. Those clinics are highly regulated at both the federal and state levels, with lots of minutia involved. Patient counseling and drug screening are required.

In contrast, a physician with a DEA X number can write a prescription for buprenorphine and have a patient fill it at a pharmacy. There is inherently less structure surrounding buprenorphine therapy than that of methadone, Dr. Grossman noted. There are no hard and fast rules about how often a physician has to see the patient or do drug screens or counseling. Buprenorphine is available as once-daily oral sublingual therapy and, more recently, in long-acting injectable and implantable formulations, although Dr. Grossman believes the jury is still out about how these nonoral agents are best utilized.

“I’m often asked, ‘Which is better, methadone or buprenorphine?’ Really, the answer is they’re both pretty darn good,” according to Dr. Grossman.

The Cochrane review concluded that, in the studies that have used real-world dosing – that is, higher doses than in the initial studies – high-dose buprenorphine and high-dose methadone have similar rates of retention in treatment.

“What I tell patients is that a lot hinges on the structure of the treatment delivery system,” Dr. Grossman said. “If it’s methadone, they’re going to the OTP every day. Some people need more structure; they need a set of eyes on them every day. Or if they are at high risk for medication diversion – for example, someone else in their household might want to steal their medications – going to a methadone program gets around that. Also, when somebody has been on methadone in the past and did well on it and wants to go on it again, I’m likely to say, ‘That sounds like a good fit.’”

Buprenorphine is a good option for patients who don’t require close, structured supervision. It has fewer drug interactions than does methadone and is less prone to cause QTc prolongation. Also, it’s a more realistic option for patients who live so far from an OTP that daily attendance is impractical. And ob.gyns increasingly favor buprenorphine, because the problem of neonatal abstinence syndrome is less severe than when mothers are on methadone.

As for extended-release naltrexone (Vivitrol), the pivotal double-blind Russian trial that won FDA approval for treatment of OUD showed a dramatic improvement in opioid-free weeks (Lancet. 2011 Apr 30;377[9776]:1506-13).

More recently, the 24-week, multicenter, open-label X:BOT trial randomized 570 U.S. patients with OUD to once-monthly extended-release naltrexone or daily sublingual buprenorphine-naloxone (Suboxone). The dropout rate was higher in the extended-release naltrexone arm because patients had to be opioid free for 2 weeks before starting on the opioid antagonist. As a practical matter, that can be difficult to achieve unless a patient has just been released from jail or prison. But the per-protocol relapse rates were similar (Lancet. 2018 Jan 27;391[10118]:309-18).

“Many people interpret this study as saying, with the right patient who can get into an opioid-free state or, if you inherit an opioid-free state, the choice between extended-release naltrexone and buprenorphine-naloxone may be a bit of a wash in terms of clinical effectiveness, as best we can detect,” Dr. Grossman explained. “That said, they’re very different experiences: One is a shot in your butt once a month, the other is something you put in your mouth once a day. Patients typically have a strong point of view regarding what they’re up for.”

Extended-release naltrexone doesn’t require a DEA waiver or attendance at an OTP. But it costs roughly $800 per injection, although many insurers do cover it after additional paperwork is completed. While Dr. Grossman does use extended-release naltrexone in her own practice, it comes with some baggage. The drug comes in a powder, which is mixed with a diluent in the office, creating a thick, frothy substance that’s slow to inject. It has to be kept refrigerated, then warmed up in time for the patient visit.

“If you live somewhere where there’s no OTP and you don’t have a DEA X number, and you have a patient with OUD who’s interested in extended-release naltrexone, it’s not crazy to think about,” she noted.
 

Duration of medical therapy

Study after study demonstrates that, when treatment stops, the risk of relapse goes up.

“We as health care providers are used to the mentality of chronic diseases, like diabetes, where you’re probably on medicine for the rest of your life,” Dr. Grossman said. “OUD is another chronic disease where you might have a patient on medication for the rest of their life, although you may not want to drum that into their head right up front. It’s kind of scary. I don’t usually talk that way with my diabetic patients when I give them their diagnosis. So, I don’t push it.

“But the reality is, to give them the best chance of health, they should be on medication for a good long time,” she added. “And that’s true for all of the OUD medications.”
 

The role of counseling

The best evidence of the utility of adjunctive counseling in the treatment of OUD comes from the landmark Prescription Opioid Addiction Treatment Study (POATS), a 653-patient multicenter trial conducted by the National Drug Abuse Treatment Network and funded by the National Institute on Drug Abuse. Participants were randomized to standard medical management including medication and a meeting with a physician every 1-2 weeks, or to standard therapy plus individual counseling with a trained substance use counselor.

To the surprise of many, given that SAMHSA guidance strongly recommends counseling and other forms of behavioral therapy, there was no difference in outcomes between the two groups (Drug Alcohol Depend. 2015 May 1;150:112-9).

Subsequent parsing of the POATS data showed that the subgroup of people who were using heroin rather than prescription pills and who actually attended at least 60% of their counseling sessions did better than if they were randomized to no counseling.

“There’s still room for quibbling about the study, but many people would say, ‘You know, it’s not a slam dunk that everybody needs counseling,’ ” the internist commented.

“So, how do we pick the right treatment for our patients with OUD? It’s what feels right for them,” Dr. Grossman cautioned. “This gets back to what we do every day in managing chronic diseases: We nudge, we encourage, we use our motivational interviewing skills to help people figure out how they can change their lives and get healthier. There’s a long list of things going on in our patients’ lives that are going to help guide that decision.

“The message here: Medication is better than no medication, but it’s not a slam dunk which medication or how,” she concluded.

[email protected]

NEW ORLEANS – Physicians committed to fighting the national opioid epidemic really need to take the 8-hour training course on addiction treatment required to obtain a Drug Enforcement Administration ‘X’ number, because it will enable them to prescribe buprenorphine, a drug with unique advantages for many affected patients, Ellie Grossman, MD, asserted at the annual meeting of the American College of Physicians.

Bruce Jancin/MDedge News

Buprenorphine (Subutex) is one of the three medications approved for treatment of opioid use disorder (OUD), along with methadone and naltrexone (Revia). And for certain patients, it’s clearly the best choice, according to Dr. Grossman, a general internist at Harvard Medical School, Boston, and the primary care lead for behavioral health integration at the Cambridge (Mass.) Health Alliance.

The DEA X number certification process, which entails obtaining a waiver through SAMHSA – the Substance Abuse and Mental Health Services Administration – is bureaucratic. It’s unpopular with many physicians. But it’s well worth 8 hours of an internist’s time to get the waiver and gain the ability to prescribe buprenorphine.

“The requirement is admittedly clunky, and many people have strong feelings about whether this is a regulation that should exist,” according to Dr. Grossman. “I myself didn’t need to have special training to prescribe methadone, a full opioid agonist that my patients could easily die from. But I did have to undergo an 8-hour training to prescribe buprenorphine, and it’s much harder to die from that drug.”

She addressed which of the three medications for OUD is the best fit in a given patient, the appropriate treatment duration, and the role of adjunctive counseling, which – spoiler alert – has been cast into question by the results of a major government-funded randomized trial.

Dr. Grossman’s overriding message: “You are saving lives by getting people on medication.”

Indeed, studies have shown that patients with OUD who receive no treatment have a sixfold increase in the standardized mortality ratio, compared with the general population. Contrast that with the less than 2-fold increased risk with medication-assisted treatment and roughly a 2.5-fold increased risk when medication is given short term to cover withdrawal and then tapered and discontinued.

Other documented benefits of long-term medication-assisted treatment of patients with OUD as described in a 2014 Cochrane review include reductions in injection drug use, crime days, HIV-related risk behaviors and seroconversion, and improved health and social functioning.

Of note, those well-documented benefits apply only to methadone, a full opioid agonist, and buprenorphine, a partial agonist, because those two drugs have been around long enough to generate long-term outcome data. Naltrexone, which has a completely different mechanism of action – it’s a full opioid antagonist – has not as of yet.
 

Individualizing medical therapy for OUD

Physicians can’t write a prescription for methadone. The drug must be administered at a certified opioid treatment program, or OTP, otherwise known as a methadone clinic. Those clinics are highly regulated at both the federal and state levels, with lots of minutia involved. Patient counseling and drug screening are required.

In contrast, a physician with a DEA X number can write a prescription for buprenorphine and have a patient fill it at a pharmacy. There is inherently less structure surrounding buprenorphine therapy than that of methadone, Dr. Grossman noted. There are no hard and fast rules about how often a physician has to see the patient or do drug screens or counseling. Buprenorphine is available as once-daily oral sublingual therapy and, more recently, in long-acting injectable and implantable formulations, although Dr. Grossman believes the jury is still out about how these nonoral agents are best utilized.

“I’m often asked, ‘Which is better, methadone or buprenorphine?’ Really, the answer is they’re both pretty darn good,” according to Dr. Grossman.

The Cochrane review concluded that, in the studies that have used real-world dosing – that is, higher doses than in the initial studies – high-dose buprenorphine and high-dose methadone have similar rates of retention in treatment.

“What I tell patients is that a lot hinges on the structure of the treatment delivery system,” Dr. Grossman said. “If it’s methadone, they’re going to the OTP every day. Some people need more structure; they need a set of eyes on them every day. Or if they are at high risk for medication diversion – for example, someone else in their household might want to steal their medications – going to a methadone program gets around that. Also, when somebody has been on methadone in the past and did well on it and wants to go on it again, I’m likely to say, ‘That sounds like a good fit.’”

Buprenorphine is a good option for patients who don’t require close, structured supervision. It has fewer drug interactions than does methadone and is less prone to cause QTc prolongation. Also, it’s a more realistic option for patients who live so far from an OTP that daily attendance is impractical. And ob.gyns increasingly favor buprenorphine, because the problem of neonatal abstinence syndrome is less severe than when mothers are on methadone.

As for extended-release naltrexone (Vivitrol), the pivotal double-blind Russian trial that won FDA approval for treatment of OUD showed a dramatic improvement in opioid-free weeks (Lancet. 2011 Apr 30;377[9776]:1506-13).

More recently, the 24-week, multicenter, open-label X:BOT trial randomized 570 U.S. patients with OUD to once-monthly extended-release naltrexone or daily sublingual buprenorphine-naloxone (Suboxone). The dropout rate was higher in the extended-release naltrexone arm because patients had to be opioid free for 2 weeks before starting on the opioid antagonist. As a practical matter, that can be difficult to achieve unless a patient has just been released from jail or prison. But the per-protocol relapse rates were similar (Lancet. 2018 Jan 27;391[10118]:309-18).

“Many people interpret this study as saying, with the right patient who can get into an opioid-free state or, if you inherit an opioid-free state, the choice between extended-release naltrexone and buprenorphine-naloxone may be a bit of a wash in terms of clinical effectiveness, as best we can detect,” Dr. Grossman explained. “That said, they’re very different experiences: One is a shot in your butt once a month, the other is something you put in your mouth once a day. Patients typically have a strong point of view regarding what they’re up for.”

Extended-release naltrexone doesn’t require a DEA waiver or attendance at an OTP. But it costs roughly $800 per injection, although many insurers do cover it after additional paperwork is completed. While Dr. Grossman does use extended-release naltrexone in her own practice, it comes with some baggage. The drug comes in a powder, which is mixed with a diluent in the office, creating a thick, frothy substance that’s slow to inject. It has to be kept refrigerated, then warmed up in time for the patient visit.

“If you live somewhere where there’s no OTP and you don’t have a DEA X number, and you have a patient with OUD who’s interested in extended-release naltrexone, it’s not crazy to think about,” she noted.
 

Duration of medical therapy

Study after study demonstrates that, when treatment stops, the risk of relapse goes up.

“We as health care providers are used to the mentality of chronic diseases, like diabetes, where you’re probably on medicine for the rest of your life,” Dr. Grossman said. “OUD is another chronic disease where you might have a patient on medication for the rest of their life, although you may not want to drum that into their head right up front. It’s kind of scary. I don’t usually talk that way with my diabetic patients when I give them their diagnosis. So, I don’t push it.

“But the reality is, to give them the best chance of health, they should be on medication for a good long time,” she added. “And that’s true for all of the OUD medications.”
 

The role of counseling

The best evidence of the utility of adjunctive counseling in the treatment of OUD comes from the landmark Prescription Opioid Addiction Treatment Study (POATS), a 653-patient multicenter trial conducted by the National Drug Abuse Treatment Network and funded by the National Institute on Drug Abuse. Participants were randomized to standard medical management including medication and a meeting with a physician every 1-2 weeks, or to standard therapy plus individual counseling with a trained substance use counselor.

To the surprise of many, given that SAMHSA guidance strongly recommends counseling and other forms of behavioral therapy, there was no difference in outcomes between the two groups (Drug Alcohol Depend. 2015 May 1;150:112-9).

Subsequent parsing of the POATS data showed that the subgroup of people who were using heroin rather than prescription pills and who actually attended at least 60% of their counseling sessions did better than if they were randomized to no counseling.

“There’s still room for quibbling about the study, but many people would say, ‘You know, it’s not a slam dunk that everybody needs counseling,’ ” the internist commented.

“So, how do we pick the right treatment for our patients with OUD? It’s what feels right for them,” Dr. Grossman cautioned. “This gets back to what we do every day in managing chronic diseases: We nudge, we encourage, we use our motivational interviewing skills to help people figure out how they can change their lives and get healthier. There’s a long list of things going on in our patients’ lives that are going to help guide that decision.

“The message here: Medication is better than no medication, but it’s not a slam dunk which medication or how,” she concluded.

[email protected]

NEW ORLEANS – Physicians committed to fighting the national opioid epidemic really need to take the 8-hour training course on addiction treatment required to obtain a Drug Enforcement Administration ‘X’ number, because it will enable them to prescribe buprenorphine, a drug with unique advantages for many affected patients, Ellie Grossman, MD, asserted at the annual meeting of the American College of Physicians.

Bruce Jancin/MDedge News

Buprenorphine (Subutex) is one of the three medications approved for treatment of opioid use disorder (OUD), along with methadone and naltrexone (Revia). And for certain patients, it’s clearly the best choice, according to Dr. Grossman, a general internist at Harvard Medical School, Boston, and the primary care lead for behavioral health integration at the Cambridge (Mass.) Health Alliance.

The DEA X number certification process, which entails obtaining a waiver through SAMHSA – the Substance Abuse and Mental Health Services Administration – is bureaucratic. It’s unpopular with many physicians. But it’s well worth 8 hours of an internist’s time to get the waiver and gain the ability to prescribe buprenorphine.

“The requirement is admittedly clunky, and many people have strong feelings about whether this is a regulation that should exist,” according to Dr. Grossman. “I myself didn’t need to have special training to prescribe methadone, a full opioid agonist that my patients could easily die from. But I did have to undergo an 8-hour training to prescribe buprenorphine, and it’s much harder to die from that drug.”

She addressed which of the three medications for OUD is the best fit in a given patient, the appropriate treatment duration, and the role of adjunctive counseling, which – spoiler alert – has been cast into question by the results of a major government-funded randomized trial.

Dr. Grossman’s overriding message: “You are saving lives by getting people on medication.”

Indeed, studies have shown that patients with OUD who receive no treatment have a sixfold increase in the standardized mortality ratio, compared with the general population. Contrast that with the less than 2-fold increased risk with medication-assisted treatment and roughly a 2.5-fold increased risk when medication is given short term to cover withdrawal and then tapered and discontinued.

Other documented benefits of long-term medication-assisted treatment of patients with OUD as described in a 2014 Cochrane review include reductions in injection drug use, crime days, HIV-related risk behaviors and seroconversion, and improved health and social functioning.

Of note, those well-documented benefits apply only to methadone, a full opioid agonist, and buprenorphine, a partial agonist, because those two drugs have been around long enough to generate long-term outcome data. Naltrexone, which has a completely different mechanism of action – it’s a full opioid antagonist – has not as of yet.
 

Individualizing medical therapy for OUD

Physicians can’t write a prescription for methadone. The drug must be administered at a certified opioid treatment program, or OTP, otherwise known as a methadone clinic. Those clinics are highly regulated at both the federal and state levels, with lots of minutia involved. Patient counseling and drug screening are required.

In contrast, a physician with a DEA X number can write a prescription for buprenorphine and have a patient fill it at a pharmacy. There is inherently less structure surrounding buprenorphine therapy than that of methadone, Dr. Grossman noted. There are no hard and fast rules about how often a physician has to see the patient or do drug screens or counseling. Buprenorphine is available as once-daily oral sublingual therapy and, more recently, in long-acting injectable and implantable formulations, although Dr. Grossman believes the jury is still out about how these nonoral agents are best utilized.

“I’m often asked, ‘Which is better, methadone or buprenorphine?’ Really, the answer is they’re both pretty darn good,” according to Dr. Grossman.

The Cochrane review concluded that, in the studies that have used real-world dosing – that is, higher doses than in the initial studies – high-dose buprenorphine and high-dose methadone have similar rates of retention in treatment.

“What I tell patients is that a lot hinges on the structure of the treatment delivery system,” Dr. Grossman said. “If it’s methadone, they’re going to the OTP every day. Some people need more structure; they need a set of eyes on them every day. Or if they are at high risk for medication diversion – for example, someone else in their household might want to steal their medications – going to a methadone program gets around that. Also, when somebody has been on methadone in the past and did well on it and wants to go on it again, I’m likely to say, ‘That sounds like a good fit.’”

Buprenorphine is a good option for patients who don’t require close, structured supervision. It has fewer drug interactions than does methadone and is less prone to cause QTc prolongation. Also, it’s a more realistic option for patients who live so far from an OTP that daily attendance is impractical. And ob.gyns increasingly favor buprenorphine, because the problem of neonatal abstinence syndrome is less severe than when mothers are on methadone.

As for extended-release naltrexone (Vivitrol), the pivotal double-blind Russian trial that won FDA approval for treatment of OUD showed a dramatic improvement in opioid-free weeks (Lancet. 2011 Apr 30;377[9776]:1506-13).

More recently, the 24-week, multicenter, open-label X:BOT trial randomized 570 U.S. patients with OUD to once-monthly extended-release naltrexone or daily sublingual buprenorphine-naloxone (Suboxone). The dropout rate was higher in the extended-release naltrexone arm because patients had to be opioid free for 2 weeks before starting on the opioid antagonist. As a practical matter, that can be difficult to achieve unless a patient has just been released from jail or prison. But the per-protocol relapse rates were similar (Lancet. 2018 Jan 27;391[10118]:309-18).

“Many people interpret this study as saying, with the right patient who can get into an opioid-free state or, if you inherit an opioid-free state, the choice between extended-release naltrexone and buprenorphine-naloxone may be a bit of a wash in terms of clinical effectiveness, as best we can detect,” Dr. Grossman explained. “That said, they’re very different experiences: One is a shot in your butt once a month, the other is something you put in your mouth once a day. Patients typically have a strong point of view regarding what they’re up for.”

Extended-release naltrexone doesn’t require a DEA waiver or attendance at an OTP. But it costs roughly $800 per injection, although many insurers do cover it after additional paperwork is completed. While Dr. Grossman does use extended-release naltrexone in her own practice, it comes with some baggage. The drug comes in a powder, which is mixed with a diluent in the office, creating a thick, frothy substance that’s slow to inject. It has to be kept refrigerated, then warmed up in time for the patient visit.

“If you live somewhere where there’s no OTP and you don’t have a DEA X number, and you have a patient with OUD who’s interested in extended-release naltrexone, it’s not crazy to think about,” she noted.
 

Duration of medical therapy

Study after study demonstrates that, when treatment stops, the risk of relapse goes up.

“We as health care providers are used to the mentality of chronic diseases, like diabetes, where you’re probably on medicine for the rest of your life,” Dr. Grossman said. “OUD is another chronic disease where you might have a patient on medication for the rest of their life, although you may not want to drum that into their head right up front. It’s kind of scary. I don’t usually talk that way with my diabetic patients when I give them their diagnosis. So, I don’t push it.

“But the reality is, to give them the best chance of health, they should be on medication for a good long time,” she added. “And that’s true for all of the OUD medications.”
 

The role of counseling

The best evidence of the utility of adjunctive counseling in the treatment of OUD comes from the landmark Prescription Opioid Addiction Treatment Study (POATS), a 653-patient multicenter trial conducted by the National Drug Abuse Treatment Network and funded by the National Institute on Drug Abuse. Participants were randomized to standard medical management including medication and a meeting with a physician every 1-2 weeks, or to standard therapy plus individual counseling with a trained substance use counselor.

To the surprise of many, given that SAMHSA guidance strongly recommends counseling and other forms of behavioral therapy, there was no difference in outcomes between the two groups (Drug Alcohol Depend. 2015 May 1;150:112-9).

Subsequent parsing of the POATS data showed that the subgroup of people who were using heroin rather than prescription pills and who actually attended at least 60% of their counseling sessions did better than if they were randomized to no counseling.

“There’s still room for quibbling about the study, but many people would say, ‘You know, it’s not a slam dunk that everybody needs counseling,’ ” the internist commented.

“So, how do we pick the right treatment for our patients with OUD? It’s what feels right for them,” Dr. Grossman cautioned. “This gets back to what we do every day in managing chronic diseases: We nudge, we encourage, we use our motivational interviewing skills to help people figure out how they can change their lives and get healthier. There’s a long list of things going on in our patients’ lives that are going to help guide that decision.

“The message here: Medication is better than no medication, but it’s not a slam dunk which medication or how,” she concluded.

[email protected]