Exogenous Testosterone May Slightly Boost Risk of Cardiovascular Events

By David L. Levine

NEW YORK - An overview of systematic reviews suggests a small but significantly increased risk of cardiovascular events associated with exogenous testosterone.

As reported online September 23 in The Lancet Diabetes and Endocrinology, the research team searched through PubMed, MEDLINE, Embase, Cochrane Collaboration Clinical Trials, ClinicalTrials.gov, and the Food and Drug Administration's website. Ultimately, out of nearly 30,000 abstracts and nearly 1,000 papers, the researchers identified seven reviews and meta-analyses of randomized controlled trials (RCTs) to include in their study.

The AMSTAR (A Measurement Tool to Assess Systematic Reviews) checklist was used to assess methodological quality of each review.

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Six of the seven studies showed no significant association between exogenous testosterone and cardiovascular events. Two showed increased risk in subgroup analyses of oral testosterone and men aged 65 years or older during the first year of treatment. One meta-analysis showed a significant association between exogenous testosterone and cardiovascular events in men aged 18 years or older.

The study team observed that an RCT would require at least 17,664 participants in each trial group to detect a true difference in cardiovascular risk between treatment groups receiving exogenous testosterone and their controls.

In email to Reuters Health, Dr. G. Caleb Alexander of the Johns Hopkins University School of Health, senior author of the study, said, "Until these studies are done, the association between exogenous testosterone and cardiovascular risk will continue to be debated, and our study highlights that even systemic reviews may yield conflicting and at times, confusing evidence."

For now, Dr. Alexander advises, healthcare professionals should make patients aware of the risks of cardiovascular events when deciding whether to start, or continue, testosterone therapy. Additional screening for cardiovascular risk factors is not recommended at this time.

In a telephone interview, Dr. Andrew M. Freeman of the National Jewish Health Center in Denver, Colorado, who co-chairs the American College of Cardiology's Nutrition and Lifestyle Work Group, said, "Although the authors did not break any new ground they did a great job of reviewing the thousands of papers on testosterone-replacement therapy and major adverse cardiovascular outcomes and identifying the best studies to base their conclusions on."

Dr Freeman, who was not involved with the study, said he agreed with the authors that a definitive RCT is needed.

"I am glad that the FDA is requiring pharmaceutical companies that produce testosterone-replacement therapy to do trials to clarify the incidence of major cardiovascular events in men," he said.

Also, he said, he wished the authors had addressed the issue of advising men who don't have endocrinology issues of the value of lifestyle changes that might lower the chances of needing testosterone therapy.

SOURCE: https://bit.ly/2dKXFV7

Lancet Diabetes Endocrinol 2016.

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