A trial testing testosterone gel in older men with mobility limitations has been stopped early because of an increased risk of cardiovascular events in the treated group.
The trial, supported by the US National Institute on Aging, was being conducted to investigate whether testosterone treatment would increase muscle mass and strength in older men with limited mobility.
In the trial, 209 men were randomly assigned to receive 10 g of a transdermal gel, containing either placebo or 100 mg of testosterone, to be applied to the skin once daily for six months. The men in the trial were an average 74 years old and had high rates of chronic diseases such as diabetes and cardiovascular disease.
The trial was stopped after a review by the study’s data and safety monitoring board, which found that 23 of the 106 men who had received testosterone experienced adverse cardiovascular-related events during the study, compared with five of the 103 men who received placebo. In addition, seven men in the testosterone group and one in the placebo group had atherosclerosis-related events. The cardiovascular-related events included myocardial infarction (MI), arrhythmias, hypertension, and one death from a suspected MI. The testosterone group did show significantly greater improvements in muscle strength.
Reporting the findings in a paper published online on June 30, 2010, in The New England Journal of Medicine, the trial investigators say that chance may have played a role in the outcomes observed and that the diversity of the adverse cardiac events that were seen makes them less easily explained by a single mechanistic explanation. They also caution against extrapolating the findings to other doses and formulations of testosterone or to other populations, particularly young men who have hypogonadism, without cardiovascular disease or limitations in mobility.