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 β3-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 (treatment-naïve) 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.

Figures

Fig. 1.

Study design.

Fig. 2.

Gender, therapeutic status and age group distribution for each drug.

Fig. 3.

Mean and median days on therapy, and persistence at 12 months, for the total population (n = 19 485).

Fig. 4.

Kaplan-Meier estimated rates of persistence with different OAB drugs in treatment-naïve patients (n = 17 890).

Fig. 5.

Kaplan-Meier estimated rates of persistence with different OAB drugs over time in the treatment-experienced patients (n = 1595).

Fig. 6.

Adherence (median Medication Possession Ratio) according to OAB medication, age category and treatment status (the reference comparator is shown as a black column in each case).