Efficacy and persistence of low-dose mirabegron (25 mg) in patients with overactive bladder: analysis in a real-world urological practice

Mirabegron is a relatively new drug to treat overactive bladder (OAB). The therapeutic doses are between 25 and 100 mg in clinical trials. We aimed to evaluate the efficacy and persistence of low-dose mirabegron (25 mg) in patients with OAB in daily urological practice. The study was a retrospective consecutive cohort of 177 OAB patients (101 male and 76 female) treated with 25 mg of mirabegron mg since January 2016 to November 2016. The therapeutic outcomes were assessed at baseline, 4, 12, and 24 weeks. Mirabegron usage was associated with a statistically significant decrease in Overactive Bladder Symptom Score, Urgency Severity Score, urge urinary incontinence, International Prostate Symptom Score (both storage and voiding symptom) at 4-week follow-up, and the therapeutic effects were further improved at 12- and 24-week follow-up. Among them, 118 patients (66.7%) and 84 patients (47.5%) were maintained on mirabegron therapy for more than 3 and 6 months, respectively. However, 29 patients (16%) had poor response with drug discontinuation within 3 months and 8 patients (4.5%) stopped medication due to adverse effects. The overall side effect was 10.2%, and the most common side effect was elevated blood pressure (2.8%) and increased post-void residual (2.8%). Between male and female patients, there was no statistical difference of symptom improvement and drug persistence rate. Low-dose mirabegron (25 mg) improves clinical outcomes in two-thirds of OAB patients with good safety profile and high persistence in daily urological practice. The therapeutic effect is similar between the genders.