Methods for a Community-Engaged Randomized Trial for Urgency Incontinence

Importance Beta-agonist medication and onabotulinumtoxinA injections are commonly used for the treatment of urgency urinary incontinence (UUI); however, there are limited comparative efficacy data to inform best practice. We describe the design and rationale for the Beta-Agonist versus ONA Trial for Urgency Urinary Incontinence (BEST), which was developed in partnership with engaged patients, stakeholders, and communities. Objectives The primary objective is to compare treatment efficacy, as measured by coprimary endpoints symptom severity and treatment satisfaction at 3 months. Secondary objectives include comparisons of quality of life, global improvement, cognitive and sexual function, complications, and to describe barriers to UUI treatment. Study Design BEST is a multisite, single-blinded, randomized trial of beta-agonist versus onabotulinumtoxinA in female participants with UUI. Patient eligibility, primary and secondary outcome measures, and substantive changes in trial design through engagement with patients, stakeholders, and communities are described. Four hundred thirty-two participants will provide 80% power to detect a 15% difference in both coprimary outcomes of treatment satisfaction and symptom severity between treatment arms at a split alpha=0.025, allowing for 20% attrition. Linear mixed-effects models following the intention-to-treat principle are planned. Results Participant enrollment began in July 2023 across 5 clinical sites. As of January 6, 2026, 396 of 432 participants (92%) have been randomized, 324 (82% of randomized) have reached the primary 3-month outcome with a 98.7% retention rate for completion of the coprimary outcomes, and 213 (54% of randomized) have reached the 12-month outcome with 94% retention rate. Conclusions The BEST design was substantively informed by patient and stakeholder input and will provide patient-important comparative efficacy data for beta-agonist versus onabotulinumtoxinA for UUI.