Cardiovascular Safety and Possible Benefit of a 5-Alpha Reductase Inhibitor among Benign Prostatic Hyperplasia Patients, A Nationally Representative Cohort of Korean Men.

Several studies suggest that 5-alpha reductase inhibitors (5ARIs) may be associated with elevated risk of cardiovascular disease (CVD). We investigated the association of 5ARI exposure and CVD incidence using the National Health Insurance Service-Health Screening Cohort, a nationally representative population-based sample of Koreans. We calculated the 4-year cumulative exposure to 5ARI for 215,003 men without prior 5ARI use. Participants were followed from January 1st, 2008 to December 31st, 2015. A subcohort of newly diagnosed benign prostatic hyperplasia (BPH) patients during 2004-2010 was also analyzed. The primary study outcome was CVD and secondary outcomes were myocardial infarction (MI) or stroke. Hazard ratios (HRs) were estimated using Cox proportional hazards models adjusted for conventional risk factors. In both the main cohort and BPH subcohort, the use of any 5ARI did not increase the risk of cardiovascular disease (HR = 1.06; 95% CI = 0.91-1.23; HR = 0.95; 95% CI = 0.88-1.03; respectively). Furthermore, as an unexpected finding, a dose-analysis among the BPH subcohort showed that the highest tertile of 5ARI exposure reduced the risk of CVD (HR = 0.82; 95% CI = 0.72-0.92;