In the latest addition to the ongoing debate over the safety of testosterone treatment, researchers report no significant increased heart attack risk in older men treated with an intramuscular form of the therapy.
“In this matched double-cohort study of more than 24,000 Medicare beneficiaries, we found that use of intramuscular testosterone therapy was not associated with an increased risk of MI,” say the authors. Furthermore, “a dose–response analysis demonstrated no increased risk in MI according to estimated cumulative dose of testosterone. These findings were robust across a range of sensitivity analyses that addressed eligibility criteria, exposure thresholds, follow-up periods, and covariate adjustment,” they add.
The study, funded by the U.S. National Institutes of Health, may help ease some fears about testosterone therapy for patients and their families, the study authors said.
“Our investigation was motivated by a growing concern, in the U.S. and internationally, that testosterone therapy increases men’s risk for cardiovascular disease, specifically heart attack and stroke,” lead researcher Jacques Baillargeon, an associate professor of epidemiology at the University of Texas Medical Branch at Galveston, said in a university news release.
“This concern has increased in the last few years based on the results of a clinical trial and two observational studies,” he said. “It is important to note, however, that there is a large body of evidence that is consistent with our finding of no increased risk of heart attack associated with testosterone use.
According to background information supplied by the researchers, the market for testosterone has grown significantly in recent years. Every year, $1.6 billion is spent on these products with the aim of boosting muscle tone and sex drive for men with so-called low T.
In fact, testosterone was associated with a possible protective effect, a reduced risk of heart attack in patients with the highest prognostic risk index for MI (HR, 0.69; 95% CI, 0.53 – 0.92), and there were no differences in risk in patients in the lower quartiles of MI prognostic score.
First author Jacques Baillargeon, PhD, of the University of Texas Medical Branch in Galveston, noted that various potential mechanisms could explain the protective effect.
“Certainly there is some literature showing plausible biologic mechanisms where testosterone could in theory confer a protective effect, such as by decreasing fat mass, increasing lean body mass, and decreasing insulin sensitivity and the lipid profile,” he said.
“Testosterone may also possess anti-inflammatory and anticoagulant properties, but likewise, there are also plausible pathways whereby it could increase cardiovascular risk, so there are arguments to be made both ways,” he said.
Patients in the study were over aged 65, and testosterone-treated patients were matched 1:3 with non-treated patients according to their composite MI prognostic index score.
Reasons for initiation of testosterone therapy included hypogonadism, sexual dysfunction, fatigue, and osteoporosis.
The team found that testosterone therapy did not raise the risk of heart attack. The study comes just two weeks after the U.S. Food and Drug Administration advised testosterone products manufacturers to include a warning label about the general risk of blood clots related to polycythemia, a rare condition that happens when the red blood cell level increases abnormally because of the testosterone treatment.
FDA stated they were investigating the risk of stroke, heart attack and death in men taking FDA-approved testosterone products. “We have been monitoring this risk and decided to reassess this safety issue based on the recent publication of two separate studies that each suggested an increased risk of cardiovascular events among groups of men prescribed testosterone therapy.”
Men with testosterone problems commonly suffer from symptoms such as loss of libido, depression, fatigue and reduced muscle mass.
The study was published in the July 2 issue of the Annals of Pharmacotherapy.