What Are Factors Contributing to Improvement of Overactive Bladder Symptoms After Alpha-1 Blocker Treatment in Patients with Both Storage and Voiding Symptoms?

Introduction: To determine the pre-treatment factors related to the improvement of overactive bladder (OAB) symptom after alpha-1 blocker monotherapy in patients with benign prostatic hyperplasia complicated by OAB (BPH/OAB).

Methods: Post-hoc analysis of a prospective study in patients with BPH/OAB, randomized to receive silodosin 8 mg (n = 157) or naftopidil 75 mg (n = 157) treatment for 12 weeks, was performed. At 12 weeks post-administration, patients were divided into 2 groups (good responder [GR] group and poor responder [PR] group), according to the improvement in the OAB symptom score (OABSS). We compared the pre-administration parameters between both groups and evaluated the factors related to OAB improvement.

Results: Of 314 patients, 159 patients (50.6%) were classified into the GR and 155 (49.4%) into the PR. International Prostate Symptom score, total OABSS, OABSS urgency-score, OABSS urgency urinary incontinence (UUI)-score, post-void residual urine volume (PVR), and selection rate of naftopidil were significantly higher in the PR than in the GR. On multivariate logistic regression analysis, larger PVR, higher OABSS-UUI-score, and the choice of naftopidil were significant risk factors for insufficient improvement of OAB symptoms.

Conclusions: Pre-treatment PVR, UUI severity, and the choice of treatment agent are predicting factors related to OAB improvement after alpha-1 blocker monotherapy in patients with BPH/OAB.