International Health News

Testosterone therapy and risk of cardiovascular events

HONG KONG, CHINA. Testosterone therapy has made it to prime time with ads on the US main network nightly news programs. The underarm gel advertised is available only by prescription in the US. Advertising campaigns of the magnitude we are seeing suggests robust sales and thus it is of interest to examine recent studies which suggest that testosterone therapy (TT) increases the risk of cardiovascular events, and in particular heart attacks.

A meta-analysis of 27 trials lasting 12 or more weeks and including 2994 older men recently appeared in the journal BMC Medicine. When all studies were included, a 54% relative risk increase in cardiovascular-related events was found with an absolute risk increase of 1.5% based on treated and placebo events. However, when the investigators examined industry supported studies vs. non-industry supported studies, for the former there was no significant increase in risk whereas for the latter, the relative risk in the treatment group was twice that in the placebo group with absolute risk increase of 5.5%. Most of the studies included were characterized by low numbers of events and thus insignificant results, but the one study with the largest number found a statistically significant 6 fold increase in risk.

A study just published in PLOS ONE looked at non-fatal heart attacks in 55,593 men following an initial prescription for testosterone. The incidence rate of MI in the 90 days following the initial prescription was compared to the rate in the years prior to the initial prescription. Among men 65 years and older, a two-fold increase in the risk of MI in the 90 days after filling the TT prescription was observed, and the risk declined to baseline between 91 and 180 days. Among younger men with a history of heart disease a two- to three-fold increase in MI was found in 90 days with no excess risk in men without such a history. Among older men, the increased risk of MI was independent of cardiovascular history, but the analysis involved a small number of cases. This study had more MI cases than all 27 studies in the meta-analysis discussed above.

Xu L, Freeman G, Cowling BJ, Schooling CM. Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials. BMC Med. 2013;11:108
Finkle WD, Greenland S, Ridgeway GK et al. Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLoS One. 2014;9:e85805

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