Factors associated with antimuscarinic drug persistence and increasing drug persistence after switching to mirabegron for overactive bladder patients

Purpose: To evaluate long-term antimuscarinic drug persistence and its associated characteristics in patients with overactive bladder (OAB) treated with antimuscarinic agents. We also assessed the efficacy and safety of switching from solifenacin to mirabegron in patients refractory to antimuscarinic therapy. Methods: In this prospective, open-label, 48-month study, 416 patients (mean age, 70.6 ± 12.4 years) were enrolled. All patients completed the overactive bladder symptom score and urgency severity score questionnaires, along with initial and follow-up uroflowmetry. All patients received antimuscarinic solifenacin 5 mg daily. Mirabegron (25 mg daily) was suggested in patients that were refractory to antimuscarinic therapy or had intolerable side effects. Results: The mean solifenacin persistence was 6.6 ± 8.1 months (range, 0.5–48 months). Only 81 (19.5%) patients had drug persistence of ≥12 months. Male sex, age, cerebral vascular accident, maximum flow rate, and post-void residual were associated with solifenacin persistence in the univariate analysis. Age (odds ratio [OR], 0.14; 95% CI, 0.08–0.21) was the only independent predictor in the multivariate logistic regression. Of the 416 patients, 171 (60.8%) changed from solifenacin to mirabegron for due to the persistence of OAB symptoms. The switch resulted in a significantly longer period of actual OAB pharmacotherapy (9.3 ± 9.2 vs 13.3 ± 9.3 months, p < 0.001). Conclusion: Long-term drug persistence of solifenacin was low during the 2-year follow-up. Age was an independent factor associated with longer drug persistence. Switching from solifenacin to mirabegron was an effective and safe alternative for OAB patients that were refractory to solifenacin treatment. Keywords: Drug persistence, Mirabegron, Muscarinic antagonist, Overactive bladder, Solifenaci