Testosterone therapy and risk of myocardial infarction: a pharmacoepidemiologic study.

BACKGROUND Recent studies have provided conflicting and controversial results about the risk of cardiovascular events, including myocardial infarction (MI), with testosterone replacement therapy (TRT). The potential adverse effects of different TRT formulations and duration of therapy on MI risk are unknown. METHODS We performed a case-control study within a cohort of 934,283 men aged 45-80 from the IMS LifeLink Health Plan Claims Database. For each case of MI, four controls were identified using density-based sampling. Rate ratios (RRs) were computed for current and past TRT users. As a sensitivity analysis, the risk of MI before and after the start of a first-time TRT prescription in the same patient was also computed. RESULTS We identified 30,066 MI cases and 120,264 corresponding controls. Current use of TRT was not associated with an increased risk of MI (RR 1.01, 95% confidence interval [CI] 0.89-1.16); first-time users did show an increased risk (RR 1.41, 95% CI 1.06-1.87; number needed to harm 305). There was no association between MI and past TRT users and no differences among the different formulations. The RRs for current use and first-time use of TRT in men with a previous history of coronary artery disease were 1.05 (95% CI 0.79-1.41) and 1.78 (95% CI 0.93-3.40), respectively. CONCLUSION In this large observational study, an association between MI and past or current TRT use was not found. However, a statistically significant association was observed between first-time TRT exposure and MI, although the absolute risk was low.