Impact of chronic exposure to 5-alpha reductase inhibitors on the risk of hospitalization for COVID-19: a case-control study in male population from two COVID-19 regional centers of Lombardy (Italy)

BACKGROUND: There are sex differences in vulnerability to Coronavirus disease 2019 (COVID-19). The coronavirus S protein mediates viral entry into target cells employing the host cellular serine protease TMPRSS2 for S-protein priming. The TMPRSS2 gene expression is responsive to androgen stimulation and it could partially explain sex differences. We hypothesized that men chronically exposed to 5-alpha reductase inhibitors (5ARIs) for benign prostate hyperplasia (BPH) have a lower risk of hospitalization for COVID-19. METHODS: This is a population-based case-control study on consecutive patients positive for SARS-CoV-2 virus who required hospitalization for COVID-19 (cases), age-matched to beneficiaries of the Lombardy Regional Health Service (controls). Data were collected by two high-volume COVID-19 regional centers of Lombardy (Italy). The primary outcome was to compare the prevalence of patients chronically exposed to 5ARIs, who required hospitalization for COVID-19, with the one of controls. RESULTS: Overall, 943 males were enrolled; 45 (4.77%) were exposed to 5ARI. COVID-19 patients aged >55 years under 5ARI treatment were significantly less than expected on the basis of the prevalence of 5ARI treatment among age-matched controls (5.57 vs. 8.14%; p=0.0083, 95%CI=0.75-3.97%). This disproportion was higher for men aged >65 (7.14 vs. 12.31%; p=0.0001, 95%CI=2.83-6.97%). Eighteen 5ARIs-patients died; the mean age of men who died was higher than those who did not: 75.98±9.29 vs. 64.78±13.57 (p