To investigate the etiology of overactive bladder (OAB) symptoms during secondary treatment following initial unsuccessful therapy with α₁-blockers in benign prostatic hyperplasia (BPH)/OAB patients.

BPH/OAB patients were selected if urinary urgency did not improve with initial α₁-blocker therapy and if dose escalation was required as secondary treatment for a period of 8 weeks. The overactive bladder symptom score (OABSS), International Prostate Symptom Score (IPSS), and uroflowmetry were evaluated. On the basis of the OABSS at the end of secondary therapy, we divided patients into two groups: patients in whom OAB symptoms improved (“resolved OAB group”) and patients in whom OAB symptoms persisted (“persistent OAB group”). Differences in subjective symptoms and objective parameters between the groups were analyzed.

OAB symptoms improved in 33 of 79 patients (42%) after secondary treatment. The changes in the total OABSS and International Prostate Symptom Score from the beginning of the secondary treatment were −2.15 and −3.97, respectively, in the resolved OAB group, indicating a significant decrease in the OABSS compared to that in the persistent OAB group (−0.91 and −1.11, respectively). The change in average flow rate (Q_ave; +1.34) from the beginning of secondary treatment in the resolved OAB group was significantly greater than the change in the persistent OAB group (+0.58). Improvements in urgency and Q_ave were significantly correlated (r = −0.264, P = .031).

Improvement in urinary stream contributed to the resolution of OAB symptoms in BPH/OAB patients. In the management of OAB symptoms in BPH/OAB patients, examination and therapy for both urinary stream and OAB symptoms could be substantially important.