Persistence and adherence with the new beta-3 receptor agonist, mirabegron, versus antimuscarinics in overactive bladder: Early experience in Canada

Abstract

Introduction: Antimuscarinics are the principal pharmacological treatment for overactive bladder (OAB), but frequently give rise to anticholinergic side effects, such as dry mouth, a factor leading to poor persistence. The ß3-adrenoceptor agonist mirabegron is devoid of significant anticholinergic activity, while being effective in OAB. We evaluated persistence and adherence with mirabegron versus antimuscarinics over 12 months.

Methods: We obtained retrospective claims from a Canadian Private Drug Plan database for patients 18 years old and over, with a first claim for mirabegron or antimuscarinics during a 6-month index period (April–September 2013). A 6-month look-back identified those with no prior claims for OAB medication (treatmentnaïve) or ≥1 prior OAB drug (treatment-experienced). Time to end of persistence (≥30 day therapy gap or switch of therapy) was evaluated over 12 months; adherence with medication (medication possession ratio) was also measured.

Results: Persistence data from 19 485 patients (74% female, 92% naïve, 19.9% aged ≥65 years) showed that for experienced patients the median number of days on mirabegron was 299 days, compared with a range of 96 to 242 days for the different antimuscarinics; for naïve patients, it was 196 versus 70 to 100 days, respectively. Persistence at 12 months was for mirabegron 39% versus 14% to 35% for antimuscarinics, (experienced) and 30% mirabegron versus 14% to 21% antimuscarinics, (naïve). Patients taking mirabegron demonstrated statistically significantly greater adherence than those taking antimuscarinics.

Conclusion: Patients who received mirabegron remained longer on treatment than those treated with antimuscarinics, and had higher 12-month persistence and adherence rates.