By Lauren Nicolle

Men given testosterone therapy to treat hypogonadism in the short-to-medium term are at no greater risk of cardiovascular events compared to men who are not receiving the treatment, new research suggests.

Until now, the effects of testosterone treatment on heart health have been unclear. Previous studies have suggested that hormone replacement therapy could increase the risk of cardiovascular events, but these studies have relied on aggregate data rather than individual participant data.

Lead author of the study, Jemma Hudson from the University of Aberdeen, says this new research provides “much-needed reassurance” to men undergoing testosterone therapy.

“Our findings could have important implications for the treatment of men with hypogonadism worldwide,” she added.

What is hypogonadism?

Hypogonadism occurs when little to no sex hormones are produced by the sex glands (or gonads), causing a low sex drive or libido.

The condition affects both men and women, but for men, hypogonadism is the result of low testosterone. Some men with the condition therefore opt to have testosterone therapy which can help to restore the sex hormone to normal levels.

However, sometimes hypogonadism occurs when a problem with brain signals affects hormone production – this is known as secondary hypogonadism.

People with secondary hypogonadism may need medication, radiation therapy or surgery in order o treat the condition.

What did the study find?

The findings are based on data from 17 clinical trials including more than 3,400 participants. Each trail included in the meta-analysis used individual patient data. In this way, the researchers were able to analyse individual adverse events.

In total, 1,750 participants received testosterone therapy and 1,681 were given placebo. The participants were mostly white, non-smokers with an average BMI of 30 kg/m2, which is considered obese. On average, the participants were on testosterone therapy for nine-and-a-half months.

A meta-analysis showed that 7.5% of participants in the testosterone group experienced a cardiovascular event compared to 7.2% in the placebo group. Patient age, smoking or diabetes status did not affect cardiovascular risk.

Furthermore, those in the testosterone group were not at increased risk of death compared to the placebo group, with six patients on testosterone therapy dying compared to 12 patients taking a placebo drug. This data, however, was limited, with only 14 of the 17 trials including individual patient data on mortality.

Were there any limitations to the study?

The authors note that the findings can only apply to men on testosterone therapy in the short-to-medium term, as there was little available data evaluating the cardiovascular safety of testosterone treatment beyond 12 months. However, the longer-term safety is now being investigated in another clinical trial.

They also add that their study only included trials which provided individual participant data. It cannot therefore be ruled out with certainty that a meta-analysis of aggregate data could alter the conclusions.