April 30, 2014 — Dr. Stephanie Page, professor at the University of Washington Harborview Medical Center, has published an editorial The Lancet Diabetes & Endocrinology calling for new randomized clinical trials to investigate the safety risks of testosterone replacement therapy.
Over 5 million American men were prescribed testosterone therapy in 2011 — a five-fold increase since 2000. Many experts are concerned that the rapid rise of testosterone therapy has not been accompanied by adequate safety studies.
Dr. Page cited two recent studies linking testosterone therapy to higher rates of heart attack, stroke, and death. However, she cautioned that these studies were not sufficient because “cumulative observational data cannot replace well-designed and undertaken randomized controlled trials.”
The longest randomized controlled trial of testosterone therapy lasted just 36 months. Although it was reassuring in terms of safety, it was not powerful enough to assess the risk of heart attack and stroke. Other studies have found contradictory results — including one clinical trial that was halted prematurely because patients on testosterone had five-times as many cardiovascular events as patients on a placebo.
Dr. Page also cautioned that concern about testosterone therapy echoes estrogen therapy. A decade ago, doctors recommended estrogen therapy to treat symptoms of menopause in women. That practice ended abruptly after studies found that estrogen therapy could increase a woman’s risk of breast cancer and heart problems.
Testosterone therapy is known to cause fluctuations in hormone levels, in some cases increasing estrogen levels in men. This can lead to complications like gynecomastia (enlargement of male breasts). Dr. Page warned:
“These concerns are not new and are reminiscent of the debate about hormone replacement therapy and heart disease in women that raged before the Women’s Health Initiative [WHI]. … As the WHI showed, the results [for testosterone therapy] might be surprising.”