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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
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