Lead author Dr. Michael Ho, a cardiologist with the VA's Eastern Colorado Health System in Denver, said the research doesn't prove testosterone caused the heart attacks, strokes or death, but echoes a previous study in older men and should prompt doctors and patients to discuss potential risks and benefits of using the products, USA Today reported.
An estimated 2.9 percent of U.S, men age 40 and older are prescribed testosterone therapy, yet there are limited randomized trial data examining the long term benefits and risks, the study said.
The study involved men in the VA system compared 1,223 men taking testosterone with 7,489 men not using testosterone and found a greater percentage of deaths, heart attacks and strokes in the testosterone group.
The study, published in the Journal of the American Medical Association, found approximately 1-in-5 men not taking the therapy had such a heart event, while more than 1-in-4 men taking testosterone had a heart attack, stroke, or died over a three-year-period.
However, Dr. Joseph J. Pinzone, a California internist and endocrinologist who was not involved in the study, said the design of the study was flawed.
"The study uses the same design as the population-based studies that led us to believe, incorrectly, for years that hormone replacement therapy lowered heart disease risk in women. Then when the Women's Health Initiative was set up as a double-blind, placebo-controlled, randomized trial of HRT vs. placebo, we found out that the most common type of HRT increases the risk of heart disease in women."
It is well-known men with too little or too much testosterone have an increase in heart disease risk, specifically coronary artery disease and it makes good medical sense to supplement testosterone in a medically-supervised and medically appropriate fashion to men who have low testosterone, Pinzone said.
"It would be useful to have a very large head-to-head trial of testosterone replacement therapy in men with low testosterone to determine definitively whether normalizing testosterone does reduce the risk of heart disease, which is the current theory. However, this current observational trial is filled with bias. The most obvious example of bias is that of the 8,709 men with low testosterone, only 1,223 were receiving testosterone replacement," Pinzone said.
"This raises several questions: 1). The replacement was not standardized since this was not a controlled study, so we can't even be sure that there was appropriate replacement in the men receiving it since they did not follow testosterone levels once the replacement was instituted. 2). Despite the fact that all the men had low testosterone, the doctors decided who should receive it and who shouldn't. They didn't make that decision at random; and with this type of study we cannot assess the reason they chose not to give testosterone replacement to 7,486 patients, or approximately 86 percent."