Mirabegron and antimuscarinic use in frail overactive bladder patients in the United States Medicare population

Introduction: Overactive bladder (OAB) and frailty are independently associated with patient burden. However, economic burden and treatment-taking behavior have not been well characterized among frail patients with OAB, which, given the varying safety and tolerability profiles of available treatments, is crucial.

Objectives: To assess costs, health care resource utilization, treatment-taking behavior (persistence and adherence) to OAB medication in older, frail OAB patients.

Methods: This was a retrospective cohort study using international business machines MarketScan Medicare Supplemental claims data. Eligible frail patients (per Claims-based Frailty Index score) initiating mirabegron were 1:2 propensity score matched (based on age, sex, and other characteristics) with those initiating antimuscarinics and were followed up to 1 year. All-cause, per-person, per-month costs, health care encounters, persistence (median days to discontinuation assessed using Kaplan-Meier methods) and adherence (≥80% of proportion of days covered at Day 365) were compared.

Results: From 2527 patients with incident mirabegron (21%) or antimuscarinic (79%) dispensations, 516 incident mirabegron users (median age: 82 years, 64% female) were matched to 1032 incident antimuscarinic users (median age: 81 years, 62% female). Median cost was higher in mirabegron group ($1581 vs. $1197 per month); this was primarily driven by medication cost. There was no difference in medical encounters. Adherence (39.1% vs. 33.8%) and persistence (103 vs. 90 days) were higher in mirabegron users.

Conclusions: Among frail older adults with OAB, mirabegron use was associated with higher costs and potential improvements in treatment-taking behaviors, particularly with respect to treatment adherence, versus those initiating antimuscarinics.