Objectives: We evaluated the types of patient factors that influence the efficacy and safety of solifenacin add-on therapy to tamsulosin in men with overactive bladder (OAB) associated with benign prostatic hyperplasia (BPH).
Methods: A total of 130 BPH patients with persistent OAB symptoms despite undergoing alpha1-adrenagic antagonist monotherapy were enrolled in this study. Their OAB symptoms persisted after monotherapy consisting of tamsulosin 0.2 mg once daily for more than 8 weeks, followed by subsequent solifenacin 5 mg once daily. The patient backgrounds were assessed, as were the changes in their International Prostate Symptom score (IPSS), Quality of Life (QOL) index, and Overactive Bladder Symptom Score (OABSS) before and 8 weeks after the administration of solifenacin.
Results: Total IPSS, QOL index, and OABSS improved significantly following solifenacin administration. Multivariate analyses revealed prostate volume was the only predictor that contributed to the improvement of total IPSS. In patients with prostate volume <30 mL, the improvement in total IPSS (−3.5) was superior to that for prostate volume >30 mL (−0.5; P = 0.002). The data also demonstrated that diabetes mellitus was an independent factor preventing OABSS improvement. In patients with diabetes mellitus, OABSS was not sufficiently improved (−0.6) compared to patients without diabetes (−2.1; P < 0.001).
Conclusion: Solifenacin add-on therapy to tamsulosin showed efficacy and good tolerability in BPH patients with OAB symptoms. The findings also indicated that patients with a relatively small prostate and without diabetes mellitus would receive more benefit from this therapy.