Testosterone Therapy May Raise Heart Attack Risk
Researchers say risk doubles after treatment starts for men under 65 with heart problems and all men over 65
"The theory is that testosterone most likely promotes clotting," he said. In older men who tend to have thinner vessels, that clotting could cause problems, he said.
The supplements might also increase men's circulating estrogen, the researchers said. Estrogen therapy has been linked to an increase in heart troubles in both men and women.
AbbVie and Actavis, the makers of testosterone therapies, did not respond to requests for comment on the study.
But one expert not involved in the research expressed skepticism, citing flaws in the study design.
"Based on the best available data, testosterone replacement still appears to be safe ... for properly selected patients," said Dr. Ryan Terlecki, director of the Men's Health Clinic at the Wake Forest Baptist Medical Center.
Among the flaws in the study, Terlecki said, was the use of information obtained from medical claims data, which makes it uncertain which men actually used the testosterone.
"This is important since compliance can be poor, especially with topical formulations," he said. Terlecki reported that he previously worked as a consultant for Auxilium, which makes testosterone therapy.
The researchers did not have information on why the testosterone therapy was prescribed, so it could have been prescribed inappropriately, Terlecki said. He also cited other data that has linked low testosterone -- not testosterone therapy -- to an increased risk of heart disease.
Men who are discussing testosterone therapy with their doctors "should add the risk of heart attack to the discussion of the risks and benefits of testosterone," Finkle said.
Terlecki said men who have a lack of energy should first see their doctor and ask about screening for depression and other conditions -- such as thyroid disease or B12 deficiency -- that could also be the cause.
Testosterone therapy is marketed so successfully that the independent medicine website Drugs.com reported that sales of Androgel exceeded sales of Viagra in 2013, according to UCLA researchers.