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Original Investigation
Published online November 6, 2013
Association of Testosterone Therapy With Mortality, Myocardial Infarction, and Stroke in Men With Low Testosterone Levels FREE
Rebecca Vigen, MD, MSCS1; Colin I. O'Donnell, MS2,3; Anna E. Barón, PhD2,3; Gary K. Grunwald, PhD2,3; Thomas M. Maddox, MD, MSc2,3,4; Steven M. Bradley, MD, MPH2,3,4; Al Barqawi, MD3; Glenn Woning, MD3; Margaret E. Wierman, MD2,3; Mary E. Plomondon, PhD2,3,4; John S. Rumsfeld, MD, PhD2,3,4; P. Michael Ho, MD, PhD2,3,4
[+] Author Affiliations
JAMA. 2013;310(17):1829-1836. doi:10.1001/jama.2013.280386.
[+] More
ABSTRACT
Jump to Section [+]
Importance Rates of testosterone therapy are increasing and the effects of testosterone therapy on cardiovascular outcomes and mortality are unknown. A recent randomized clinical trial of testosterone therapy in men with a high prevalence of cardiovascular diseases was stopped prematurely due to adverse cardiovascular events raising concerns about testosterone therapy safety.
Objectives To assess the association between testosterone therapy and all-cause mortality, myocardial infarction (MI), or stroke among male veterans and to determine whether this association is modified by underlying coronary artery disease.
Design, Setting, and Patients A retrospective national cohort study of men with low testosterone levels (<300 ng/dL) who underwent coronary angiography in the Veterans Affairs (VA) system between 2005 and 2011.
Main Outcomes and Measures Primary outcome was a composite of all-cause mortality, MI, and ischemic stroke.
Results Of the 8709 men with a total testosterone level lower than 300 ng/dL, 1223 patients started testosterone therapy after a median of 531 days following coronary angiography. Of the 1710 outcome events, 748 men died, 443 had MIs, and 519 had strokes. Of 7486 patients not receiving testosterone therapy, 681 died, 420 had MIs, and 486 had strokes. Among 1223 patients receiving testosterone therapy, 67 died, 23 had MIs, and 33 had strokes. The absolute rate of events were 19.9% in the no testosterone therapy group vs 25.7% in the testosterone therapy group, with an absolute risk difference of 5.8% (95% CI, -1.4% to 13.1%) at 3 years after coronary angiography. In Cox proportional hazards models adjusting for the presence of coronary artery disease, testosterone therapy use as a time-varying covariate was associated with increased risk of adverse outcomes (hazard ratio, 1.29; 95% CI, 1.04 to 1.58). There was no significant difference in the effect size of testosterone therapy among those with and without coronary artery disease (test for interaction, P = .41).
Conclusions and Relevance Among a cohort of men in the VA health care system who underwent coronary angiography and had a low serum testosterone level, the use of testosterone therapy was associated with increased risk of adverse outcomes. These findings may inform the discussion about the potential risks of testosterone therapy.
To determine whether testosterone therapy is associated with all-cause mortality, myocardial infarction, or stroke, Ho and coauthors conducted a retrospective study involving 8709 men with testosterone levels lower than 300 ng/dL who underwent coronary angiography in the Veterans Affairs system. In an Editorial, Cappola discusses testosterone use and cardiovascular risk.
Rates of testosterone therapy prescription have increased markedly in the United States over the past decade. Annual prescriptions for testosterone increased by more than 5-fold from 20001 to 2011, reaching 5.3 million prescriptions and a market of $1.6 billion in 2011.2,3 Professional society guidelines recommend testosterone therapy for patients with symptomatic testosterone deficiency.4 In addition to improving sexual function5- 7 and bone mineral density8,9 and increasing free-fat mass8,9 and strength,10 treatment with testosterone has been shown to improve lipid profiles11- 13 and insulin resistance11,12 and increase the time to ST depression during stress testing.14,15
The effects of testosterone therapy on cardiovascular outcomes and mortality are unknown. Prior clinical studies of testosterone therapy have not detected adverse cardiac events, but these trials were generally focused on intermediate end points, of short duration, and not powered for clinical end points. A recent trial, the Testosterone in Older Men with Mobility Limitations (TOM) trial,16 conducted in older frail men with a high prevalence of cardiovascular diseases was stopped prematurely due to increased cardiovascular events in the treatment group. The premature termination of the TOM trial and the limitations of the prior studies highlight uncertainty regarding the safety of testosterone therapy in older men with cardiovascular diseases.
To address this gap in knowledge, we evaluated the association between the use of testosterone therapy and all-cause mortality, myocardial infarction (MI), and stroke among male veterans and whether this association was modified by underlying coronary artery disease (CAD).
METHODS
Jump to Section [+]
The VA Clinical Assessment Reporting and Tracking (CART) Program uses a customized software application that collects patient and procedural data at the point-of-care for all procedures performed in the 76 VA cardiac catheterization laboratories nationwide.17,18 It is designed to simultaneously allow for data entry by clinicians during routine clinical workflow, integrate into the VA's electronic medical record system, and collect individual and aggregate data to support quality management and improvement initiatives for cardiovascular procedures. CART was initially implemented in 2005 and was actively used in all VA catheterization laboratories by 2009. The methods of its implementation have been previously described.17 This study was approved by the Colorado Multiple Institutional Review Board.
Patient Population
This was a retrospective cohort study of all male veterans who underwent coronary angiography between 2005 and 2011 and who had a total testosterone level checked. Patients who started testosterone therapy prior to coronary angiography were excluded because we could not ascertain the effect of testosterone therapy treatment on underlying burden of coronary disease. Additionally, patients who started testosterone therapy prior to having a testosterone level checked in the VA were excluded because we did not know if the patient had low testosterone levels prior to treatment. Patients with missing coronary anatomy data and those who were prescribed testosterone therapy after an MI were excluded. Patients with a hematocrit of more than 50% and a prostate-specific antigen (PSA) level of 4.0 ng/mL or higher were excluded because these are contraindications to testosterone therapy per guidelines.4 The final cohort was limited to patients who had a total testosterone level less than 300 ng/dL (to convert to nanomoles per liter, multiply by 0.0347) because this is a generally agreed threshold for biochemical hypogonadism per the Endocrine Society Clinical Practice Guidelines.4
Covariates
Patient characteristics and presence of CAD were obtained via CART and VA administrative data.18 Patient characteristics are entered into CART at the time of coronary angiography by physicians performing the procedure in the cardiac catheterization laboratory. Covariates not present in CART were obtained from VA administrative data, the majority of which were derived from Elixhauser codes. Total testosterone levels were obtained from VA laboratory files, and the level closest in timing to the procedure date was included in this analysis. Coronary artery disease was present if there was 20% or more stenosis in any epicardial vessel as recorded in CART by the physician performing the procedure. No evidence of CAD was defined as less than 20% stenosis in all epicardial vessels on angiography. These definitions were chosen based on standardized definitions of flow-limiting stenosis.19,20
Primary Exposure Variable
Patients were categorized as initiating testosterone therapy if they filled a prescription for testosterone gel, patch, or injections following coronary angiography based on pharmacy-dispensing data (VHA Decision Support System). Once initiated, a patient was assumed to have continued treatment until an outcome event occurred or the end of follow-up. Testosterone therapy is generally prescribed long-term with recommendations for assessment of response and adverse effects at 3 months following initiation and then annually thereafter.4
Outcome Variable
The primary end point was a combined end point of time to all-cause mortality or to hospitalization for MI or ischemic stroke. All-cause mortality was assessed via the VA vital status file. The file has 98.3% sensitivity and 97.6% exact agreement with the National Death Index.21,22 Myocardial infarction and ischemic stroke were assessed via International Classification of Diseases, Ninth Revision (ICD-9) codes (410.x0 and 410.x1) and (433.x or 444.x), respectively, from VA inpatient treatment files. The last day of follow-up was January 23, 2012.
Statistical Methods
Because patients were not randomized to receive testosterone therapy, we used stabilized inverse probability of treatment weighting to adjust for any unmeasured confounders that may have affected when and if patients were prescribed testosterone therapy. Variables used to create these weights included demographic characteristics (age, race), comorbidities (prior MI, congestive heart failure, diabetes, renal failure, depression, posttraumatic stress disorder, hyperlipidemia, peripheral vascular disease, chronic pulmonary disease, chronic obstructive pulmonary disease, obstructive sleep apnea, hypertension, cerebrovascular disease, overweight, dialysis, ever smoker, alcohol, anemia, blood loss anemia, coagulation disorder, complicated diabetes, uncomplicated diabetes, drug abuse, fluid electrolyte disorder, human immunodeficiency syndrome or AIDS, hypothyroidism, liver disease, lymphoma, metastatic cancer, neurological disorder, paralysis, peptic ulcer disease, psychoses, pulmonary circulatory disorder, renal failure, rheumatoid arthritis, nonmetastatic tumor, and weight loss), and procedures (prior revascularization, prior catheterization, prior percutaneous coronary intervention [PCI], prior coronary artery bypass graft surgery, cardiac transplant, prior stress test, prior cardiac blood pool imaging, cardiac magnetic resonance imaging, cardiac computed tomography [CT], CT coronary angiography, prior myocardial perfusion imaging, prior transthoracic echocardiogram, and prior transesophageal echocardiogram).
We applied stabilized weights for each patient in the cohort at each time that an event was observed.23 Treating testosterone therapy as a time-varying covariate, Cox proportional hazards models with stabilized inverse probability of treatment weighting were used to assess the association between testosterone therapy and the primary outcome of death, MI, or stroke. Next, we adjusted for the presence of CAD and then tested for an interaction between CAD status and testosterone therapy. We wanted to determine whether the association of testosterone therapy with adverse outcomes was modified by the presence of CAD given the uncertainty regarding the safety of testosterone therapy in older men with comorbidities such as CAD.
Original Investigation
Published online November 6, 2013
Association of Testosterone Therapy With Mortality, Myocardial Infarction, and Stroke in Men With Low Testosterone Levels FREE
Rebecca Vigen, MD, MSCS1; Colin I. O'Donnell, MS2,3; Anna E. Barón, PhD2,3; Gary K. Grunwald, PhD2,3; Thomas M. Maddox, MD, MSc2,3,4; Steven M. Bradley, MD, MPH2,3,4; Al Barqawi, MD3; Glenn Woning, MD3; Margaret E. Wierman, MD2,3; Mary E. Plomondon, PhD2,3,4; John S. Rumsfeld, MD, PhD2,3,4; P. Michael Ho, MD, PhD2,3,4
[+] Author Affiliations
JAMA. 2013;310(17):1829-1836. doi:10.1001/jama.2013.280386.
[+] More
ABSTRACT
Jump to Section [+]
Importance Rates of testosterone therapy are increasing and the effects of testosterone therapy on cardiovascular outcomes and mortality are unknown. A recent randomized clinical trial of testosterone therapy in men with a high prevalence of cardiovascular diseases was stopped prematurely due to adverse cardiovascular events raising concerns about testosterone therapy safety.
Objectives To assess the association between testosterone therapy and all-cause mortality, myocardial infarction (MI), or stroke among male veterans and to determine whether this association is modified by underlying coronary artery disease.
Design, Setting, and Patients A retrospective national cohort study of men with low testosterone levels (<300 ng/dL) who underwent coronary angiography in the Veterans Affairs (VA) system between 2005 and 2011.
Main Outcomes and Measures Primary outcome was a composite of all-cause mortality, MI, and ischemic stroke.
Results Of the 8709 men with a total testosterone level lower than 300 ng/dL, 1223 patients started testosterone therapy after a median of 531 days following coronary angiography. Of the 1710 outcome events, 748 men died, 443 had MIs, and 519 had strokes. Of 7486 patients not receiving testosterone therapy, 681 died, 420 had MIs, and 486 had strokes. Among 1223 patients receiving testosterone therapy, 67 died, 23 had MIs, and 33 had strokes. The absolute rate of events were 19.9% in the no testosterone therapy group vs 25.7% in the testosterone therapy group, with an absolute risk difference of 5.8% (95% CI, -1.4% to 13.1%) at 3 years after coronary angiography. In Cox proportional hazards models adjusting for the presence of coronary artery disease, testosterone therapy use as a time-varying covariate was associated with increased risk of adverse outcomes (hazard ratio, 1.29; 95% CI, 1.04 to 1.58). There was no significant difference in the effect size of testosterone therapy among those with and without coronary artery disease (test for interaction, P = .41).
Conclusions and Relevance Among a cohort of men in the VA health care system who underwent coronary angiography and had a low serum testosterone level, the use of testosterone therapy was associated with increased risk of adverse outcomes. These findings may inform the discussion about the potential risks of testosterone therapy.
To determine whether testosterone therapy is associated with all-cause mortality, myocardial infarction, or stroke, Ho and coauthors conducted a retrospective study involving 8709 men with testosterone levels lower than 300 ng/dL who underwent coronary angiography in the Veterans Affairs system. In an Editorial, Cappola discusses testosterone use and cardiovascular risk.
Rates of testosterone therapy prescription have increased markedly in the United States over the past decade. Annual prescriptions for testosterone increased by more than 5-fold from 20001 to 2011, reaching 5.3 million prescriptions and a market of $1.6 billion in 2011.2,3 Professional society guidelines recommend testosterone therapy for patients with symptomatic testosterone deficiency.4 In addition to improving sexual function5- 7 and bone mineral density8,9 and increasing free-fat mass8,9 and strength,10 treatment with testosterone has been shown to improve lipid profiles11- 13 and insulin resistance11,12 and increase the time to ST depression during stress testing.14,15
The effects of testosterone therapy on cardiovascular outcomes and mortality are unknown. Prior clinical studies of testosterone therapy have not detected adverse cardiac events, but these trials were generally focused on intermediate end points, of short duration, and not powered for clinical end points. A recent trial, the Testosterone in Older Men with Mobility Limitations (TOM) trial,16 conducted in older frail men with a high prevalence of cardiovascular diseases was stopped prematurely due to increased cardiovascular events in the treatment group. The premature termination of the TOM trial and the limitations of the prior studies highlight uncertainty regarding the safety of testosterone therapy in older men with cardiovascular diseases.
To address this gap in knowledge, we evaluated the association between the use of testosterone therapy and all-cause mortality, myocardial infarction (MI), and stroke among male veterans and whether this association was modified by underlying coronary artery disease (CAD).
METHODS
Jump to Section [+]
The VA Clinical Assessment Reporting and Tracking (CART) Program uses a customized software application that collects patient and procedural data at the point-of-care for all procedures performed in the 76 VA cardiac catheterization laboratories nationwide.17,18 It is designed to simultaneously allow for data entry by clinicians during routine clinical workflow, integrate into the VA's electronic medical record system, and collect individual and aggregate data to support quality management and improvement initiatives for cardiovascular procedures. CART was initially implemented in 2005 and was actively used in all VA catheterization laboratories by 2009. The methods of its implementation have been previously described.17 This study was approved by the Colorado Multiple Institutional Review Board.
Patient Population
This was a retrospective cohort study of all male veterans who underwent coronary angiography between 2005 and 2011 and who had a total testosterone level checked. Patients who started testosterone therapy prior to coronary angiography were excluded because we could not ascertain the effect of testosterone therapy treatment on underlying burden of coronary disease. Additionally, patients who started testosterone therapy prior to having a testosterone level checked in the VA were excluded because we did not know if the patient had low testosterone levels prior to treatment. Patients with missing coronary anatomy data and those who were prescribed testosterone therapy after an MI were excluded. Patients with a hematocrit of more than 50% and a prostate-specific antigen (PSA) level of 4.0 ng/mL or higher were excluded because these are contraindications to testosterone therapy per guidelines.4 The final cohort was limited to patients who had a total testosterone level less than 300 ng/dL (to convert to nanomoles per liter, multiply by 0.0347) because this is a generally agreed threshold for biochemical hypogonadism per the Endocrine Society Clinical Practice Guidelines.4
Covariates
Patient characteristics and presence of CAD were obtained via CART and VA administrative data.18 Patient characteristics are entered into CART at the time of coronary angiography by physicians performing the procedure in the cardiac catheterization laboratory. Covariates not present in CART were obtained from VA administrative data, the majority of which were derived from Elixhauser codes. Total testosterone levels were obtained from VA laboratory files, and the level closest in timing to the procedure date was included in this analysis. Coronary artery disease was present if there was 20% or more stenosis in any epicardial vessel as recorded in CART by the physician performing the procedure. No evidence of CAD was defined as less than 20% stenosis in all epicardial vessels on angiography. These definitions were chosen based on standardized definitions of flow-limiting stenosis.19,20
Primary Exposure Variable
Patients were categorized as initiating testosterone therapy if they filled a prescription for testosterone gel, patch, or injections following coronary angiography based on pharmacy-dispensing data (VHA Decision Support System). Once initiated, a patient was assumed to have continued treatment until an outcome event occurred or the end of follow-up. Testosterone therapy is generally prescribed long-term with recommendations for assessment of response and adverse effects at 3 months following initiation and then annually thereafter.4
Outcome Variable
The primary end point was a combined end point of time to all-cause mortality or to hospitalization for MI or ischemic stroke. All-cause mortality was assessed via the VA vital status file. The file has 98.3% sensitivity and 97.6% exact agreement with the National Death Index.21,22 Myocardial infarction and ischemic stroke were assessed via International Classification of Diseases, Ninth Revision (ICD-9) codes (410.x0 and 410.x1) and (433.x or 444.x), respectively, from VA inpatient treatment files. The last day of follow-up was January 23, 2012.
Statistical Methods
Because patients were not randomized to receive testosterone therapy, we used stabilized inverse probability of treatment weighting to adjust for any unmeasured confounders that may have affected when and if patients were prescribed testosterone therapy. Variables used to create these weights included demographic characteristics (age, race), comorbidities (prior MI, congestive heart failure, diabetes, renal failure, depression, posttraumatic stress disorder, hyperlipidemia, peripheral vascular disease, chronic pulmonary disease, chronic obstructive pulmonary disease, obstructive sleep apnea, hypertension, cerebrovascular disease, overweight, dialysis, ever smoker, alcohol, anemia, blood loss anemia, coagulation disorder, complicated diabetes, uncomplicated diabetes, drug abuse, fluid electrolyte disorder, human immunodeficiency syndrome or AIDS, hypothyroidism, liver disease, lymphoma, metastatic cancer, neurological disorder, paralysis, peptic ulcer disease, psychoses, pulmonary circulatory disorder, renal failure, rheumatoid arthritis, nonmetastatic tumor, and weight loss), and procedures (prior revascularization, prior catheterization, prior percutaneous coronary intervention [PCI], prior coronary artery bypass graft surgery, cardiac transplant, prior stress test, prior cardiac blood pool imaging, cardiac magnetic resonance imaging, cardiac computed tomography [CT], CT coronary angiography, prior myocardial perfusion imaging, prior transthoracic echocardiogram, and prior transesophageal echocardiogram).
We applied stabilized weights for each patient in the cohort at each time that an event was observed.23 Treating testosterone therapy as a time-varying covariate, Cox proportional hazards models with stabilized inverse probability of treatment weighting were used to assess the association between testosterone therapy and the primary outcome of death, MI, or stroke. Next, we adjusted for the presence of CAD and then tested for an interaction between CAD status and testosterone therapy. We wanted to determine whether the association of testosterone therapy with adverse outcomes was modified by the presence of CAD given the uncertainty regarding the safety of testosterone therapy in older men with comorbidities such as CAD.