Do 5α-reductase inhibitors prevent secondary benign prostate hyperplasia-related urinary retention?

Objective: The objective of this study is to determine whether 5α-reductase inhibitors (5ARIs) prevent secondary benign prostate hyperplasia (BPH)-related acute urinary retention (AUR) after the first episode of urine retention. Materials and Methods: In total, 1161 patients were enrolled using the International Classification of Diseases, Ninth Revision (ICD-9) codes as having AUR (ICD-9 code 788.20) and BPH, with or without lower urinary tract symptoms (ICD-9 codes 600.0 and 600.1) between January 2006 and June 2016. After excluding patients with bladder and external sphincter dysfunction, we enrolled 128 patients in this study. Patients were divided into two groups: Group 1 comprising 33 patients receiving 5ARI (dutasteride) and α-blocker treatment, and Group 2 comprising 95 patients receiving α-blocker treatment alone. Patient characteristics, namely, age, prostate size, maximal urinary flow rate (Qmax), prostate-specific antigen (PSA) level, and duration of dutasteride treatment, were recorded and compared. Patients were followed for at least 6 months to a maximum period of 24 months if no event occurred. Events of secondary BPH-related AUR and surgery were recorded. Results: All patient characteristics, except for prostate size, were similar between the two groups (Group 1 vs. Group 2: 65.0 vs. 36.9 mL, P = 0.001). In total, 43 patients (32%) experienced secondary AUR within 24 months. The rate of secondary BPH-related AUR was significantly lower in the Group 1 than in the Group 2 (18.2% vs. 39.4%, P = 0.030). The rate of BPH-related surgery was lower in the Group 1 (9.1% vs. 14.9%, P = 0.410), although the difference was not significant. Prostate size and PSA levels were significantly lower in the Group 1 (23.5%) than in the Group 2 (60.4%) (P < 0.001). Conclusions: Using 5ARIs to treat patients with first episodes of BPH-related AUR significantly prevents secondary AUR.