Trial Design for Mixed Urinary Incontinence: Midurethral Sling Versus Botulinum Toxin A.

Importance: Mixed urinary incontinence (MUI) is common and can be challenging to manage.

Objectives: We present the protocol design and rationale of a trial comparing the efficacy of 2 procedures for the treatment of women with MUI refractory to oral treatment. The Midurethral sling versus Botulinum toxin A ( MUSA) trial compares the efficacy of intradetrusor injection of 100 U of onabotulinimtoxinA (an office-based procedure directed at the urgency component) versus midurethral sling (MUS) placement (a surgical procedure directed at the stress component).

Study design: The MUSA is a multicenter, randomized trial of women with MUI electing to undergo procedural treatment for MUI at 7 clinical centers in the NICHD Pelvic Floor Disorders Network. Participants are randomized to either onabotulinumtoxinA 100 U or MUS. OnabotulinimtoxinA recipients may receive an additional injection between 3 and 6 months. Participants may receive additional treatment (including crossover to the alternative study intervention) between 6 and 12 months. The primary outcome is change from baseline in Urogenital Distress Inventory (UDI) at 6 months. Secondary outcomes include change in UDI at 3 and 12 months, irritative and stress subscores of the UDI, urinary incontinence episodes, predictors of poor treatment response, quality of life and global impression outcomes, adverse events, use of additional treatments, and cost effectiveness.

Results: Recruitment and randomization of 150 participants is complete and participants are currently in the follow-up phase.

Conclusions: This trial will provide information to guide care for women with MUI refractory to oral treatment who seek surgical treatment with either onabotulinumtoxinA or MUS.