Treatment Persistence and Adherence with Overactive Bladder Medications in Taiwan: A Retrospective Database Analysis

Background: Overactive bladder (OAB) is commonly treated with mirabegron or antimuscarinics, but real-world evidence on treatment persistence, adherence, and fall/fracture outcomes in Taiwan remains limited. Objective: To assess treatment persistence, adherence, and associated outcome rates of falls/fractures, in patients receiving OAB treatment with mirabegron or antimuscarinics in Taiwan. Design setting and participants: Retrospective, longitudinal, observational study of routine clinical practice within the Taiwanese National Health Insurance Research Database. Eligibility: age ≥20 years; ≥1 dispensing for a new OAB index drug (January 1, 2012 to December 31, 2018); continuous enrollment 1 year before and after index prescription date. Intervention: OAB Treatment with mirabegron or antimuscarinics. Outcome measurements and statistical analysis: Primary endpoint: treatment persistence (time to discontinuation [TTD] or switch) and adherence (proportion of days covered [PDC]); secondary endpoint: incidence of falls/fractures. Multivariate Cox proportional hazards analyses were applied to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs), describing associations between treatment groups and outcomes. Results and limitations: Overall, 1,954,544 patients were eligible (median age 60 years). Median (interquartile range [IQR]) TTD was longer with mirabegron (56 [19-168] days) than antimuscarinics (14 [5-42] days) (risk of discontinuation aHR 1.58 [95% CI 1.55-1.61]; p < 0.001). Median (IQR) PDC was significantly higher with mirabegron (0.18 [0.06-0.52]) than antimuscarinics (0.03 [0.01-0.12]; p < 0.001). Mirabegron and antimuscarinics had no statistically significant difference in the risk of composite falls/fractures (aHR 1.05 [95% CI 0.91-1.20]; p = 0.519), falls (1.33 [0.66-2.68]; p = 0.431), and fractures (1.04 [0.90-1.19]; p = 0.623). Conclusions: Persistence and adherence were significantly greater with mirabegron than antimuscarinics in patients receiving OAB treatment in Taiwan. No statistically significant association was observed for the incidence of falls/fractures between treatment groups. However, given the wide 95% CIs, the findings should not be interpreted as equivalence.