A prospective study of elderly initiating mirabegron versus antimuscarinics: Patient reported outcomes from the Overactive Bladder Satisfaction Scales and other instruments.

Aims: To understand differences in patient reported outcomes (PRO) between patients initiating mirabegron or an antimuscarinic using a validated PRO instrument, OAB-Satisfaction (OAB-S).

Methods: This prospective observational study used real-time prescription claims from Humana to identify Medicare patients initiating mirabegron or an antimuscarinic to participate in a series of three phone surveys over ninety days.

Results: A total of 1897 mirabegron and 2444 randomly selected antimuscarinic initiators were identified; 174 mirabegron and 193 antimuscarinic initiators completed all three surveys. Among responders, mirabegron initiators were slightly older (76 vs 75 years, P = 0.032), included more males (32% vs 23%, P = 0.044), more likely to have prior OAB treatment (21% vs 13%, P = 0.048), and had greater medication burden (number of unique medications: 10.0 vs 8.7, P = 0.014). There were no between-group differences at any time or on any OAB-S scale. There were significant within-group differences at follow-up compared to baseline for OAB-S scales: "impact on daily living," with improvement over the 90-day survey period for both mirabegron (P = 0.008) and antimuscarinic (P < 0.001); "interruption of day-to-day life," with improvement for both mirabegron (P < 0.001) and antimuscarinic (P < 0.001); and improvement in "OAB control" for mirabegron (P < 0.001) and antimuscarinic (P < 0.001).

Conclusions: Mirabegron initiators tended to be older, had a greater number of unique medications and previously tried prescriptions to treat OAB; nonetheless, mirabegron, and antimuscarinic initiators reported similar trends in improvement in PROs over the first 90 days of treatment. Significant improvement in daily impact of OAB was observed after treatment initiation; however, no significant differences between groups were observed.