Many older men consider taking testosterone with the goal of boosting muscle strength and sexual function; however, some avoid it because they are concerned of an increased risk of a heart attack. A new study of 24,000 Medicare patients reported that testosterone therapy did not increase the risk of heart attack, and it even lowered the risk of heart attack by 31% in a group of men at increased risk for a heart attack. The findings were published online on July 2 in the Annals of Pharmacotherapy by researchers at the University of Texas Medical Branch, Galveston, Texas.
The study authors note that testosterone prescriptions for older men in the US have increased more than 300% during the past decade. They contend that this trend has been driven by increases in direct-to-consumer marketing, the rapid growth in the number of clinics specializing in the treatment of low testosterone, the development of new drugs and improved delivery mechanisms, particularly dermal gels (gels applied to the skin), and the greater diagnostic awareness of primary and secondary low testosterone levels (“low T”). They explain that despite the widespread promotion and use of testosterone therapy in older men, its risks are not well understood. Clinical trials examining testosterone therapy have not yielded definitive evidence of adverse effects, particularly cardiovascular events (e.g., heart attacks and strokes).
In view of the foregoing, the researchers conducted a study to assess the risk of myocardial infarction (heart attack) among a groups of older men receiving intramuscular testosterone. The study group comprised 6,355 men who represented a 5% national sample of Medicare recipients; the men had received at least one testosterone injection of testosterone from January 1, 1997 through December 31, 2005. They matched this group of men to 19,065 testosterone nonusers at a 1:3 ratio based on a composite myocardial infarction risk score. The men were followed up to December 31, 2005, or until they lost coverage from Medicare, enrolled in a health maintenance organization (HMO), suffered a heart attack, or died.
The data was subjected to statistical analysis that was adjusted for demographic and patient characteristics. The investigators found that undergoing testosterone therapy was not associated with an increased risk of a myocardial infarction. They also found a relationship between undergoing testosterone therapy and a quartile of risk of a myocardial infarction. For men in the highest quartile (upper 25%) of the myocardial risk score, testosterone therapy was associated with a reduced risk of a myocardial infarction (31% reduced risk). However, there was no difference in risk for the first, second, and third quartiles.
The authors concluded that older men who received intramuscular testosterone did not appear to have an increased risk of a myocardial infarction. Furthermore, among men with a high myocardial infarction risk, testosterone use was moderately protective against a myocardial infarction.
Take home message:
This study provides reassurance for men who are ore are contemplating receiving testosterone therapy. Also, because, these men were medically supervised, they received an amount of testosterone that would return the level to the normal range (as assessed by laboratory tests). Exceeding normal testosterone levels does increase the risk of a cardiovascular event.