Finasteride Associated with 3.5-Point Lower Rate of Severe STEMI Complications in Registry Analysis

The observational registry study matched 1,069 finasteride-treated Swedish men who underwent primary angioplasty for ST-elevation myocardial infarction with similar patients not receiving androgen-modulating drugs. Outcomes included cardiac arrest, conduction blocks, severe left-ventricular dysfunction, and 30-day death. The absolute risk reduction was driven mainly by lower rates of pump failure and arrhythmia. Researchers hypothesized that 5-alpha-reductase inhibition lowers dihydrotestosterone-mediated inflammation during acute ischemia, consistent with prior mechanistic data on testosterone and infarct size.

Two supporting lines of evidence strengthen the finding. A 2019 NEJM review of sex steroids in cardiovascular disease documented testosterone's pro-inflammatory effects on macrophages and neutrophils during reperfusion. A 2023 Lancet observational analysis of androgen-deprivation therapy in prostate-cancer patients reported increased rather than decreased cardiac events, highlighting that the finasteride signal is drug- and dose-specific rather than a class effect of androgen suppression.

The study missed granular dosing, duration of finasteride exposure, and testosterone levels at admission, limiting causal inference. Residual confounding by healthier lifestyle or earlier medical contact among men receiving prostate therapy remains possible. No benefit was seen in the smaller prostate-cancer hormone-therapy subgroup.

A next-step randomized trial restricted to men with elevated dihydrotestosterone and recent STEMI would test whether short-term finasteride reduces infarct size on MRI and 90-day heart-failure hospitalization.