The Association of 5-α Reductase Inhibitors for Benign Prostatic Hyperplasia with Development of Male Breast Disease and Erectile Dysfunction: A Retrospective Cohort Study of TriNetX Database.

OBJECTIVE: To evaluate the association of 5-α reductase inhibitors (5ARIs; finasteride and dutasteride) with male breast cancer (MBC), gynecomastia, and erectile dysfunction (ED) among men treated for benign prostatic hyperplasia (BPH). METHODS: We queried the TriNetX database-Research Network. The exposure of interest was 5ARI. We propensity score matched(PSM) for demographic features, comorbidities and MBC risk factors. Outcomes included risk of MBC, gynecomastia and ED. RESULTS: 5-ARI cohort(N=553 628) and non-5ARI cohort(N=2 729 063) before PSM and 550 622 patients in each cohort after. Follow up of median 2.95 years and interquartile range(IQR) of 5.14 years in the 5ARI cohort versus median 2.94 years(IQR:5.44) in the non-5ARI cohort. Patients in the 5ARI cohort were not associated with a increased risk of MBC(RR 1.09; 95%CI:0.94-1.27). There was an increased risk of gynecomastia(RR 1.55, 95%CI:1.49-1.62) and ED(RR 1.17, 95%CI:1.15-1.18) associated with the use of 5ARI. On subgroup analysis, both finasteride(RR 1.12; 95%CI: 0.96-1.32) and dutasteride(RR 0.94; 95%CI: 0.67-1.32) were not associated with MBC. Both finasteride and dutasteride were associated with an increased risk of gynecomastia and ED, with stronger associations observed for dutasteride(gynecomastia: RR 2.13, 95% CI:1.92-2.35; ED: RR 1.40, 95% CI:1.35-1.45) than finasteride(gynecomastia: RR 1.48, 95% CI:1.42-1.54; ED: RR 1.14, 95% CI:1.12-1.15). CONCLUSIONS: In this multi-institutional retrospective cohort study, we did not find an increased risk of MBC associated with 5ARI use.