Concurrent Retropubic Midurethral Sling and OnabotulinumtoxinA for Mixed Urinary Incontinence: A Randomized Controlled Trial

OBJECTIVE: To evaluate whether retropubic midurethral sling combined with onabotulinumtoxinA is more effective than sling alone in improving mixed urinary incontinence symptoms. METHODS: We conducted a prospective, double-blind, randomized, controlled trial of women with mixed urinary incontinence, planning to undergo midurethral sling. Women were randomly assigned to receive 100 unites of intradetrusor onabotulinumtoxinA or placebo during surgery. Participants completed the PGI-S (Patient Global Impression of Severity), the UDI-6 (Urinary Distress Inventory, Short Form), and the PFIQ-7 (Pelvic Floor Impact Questionnaire-Short Form 7) before and 3 months after surgery, and the primary outcome, PGI-I (Patient Global Impression of Improvement), 3 months postoperatively. Primary outcome was PGI-I score at 3 months for overall incontinence. We considered women "improved" with answers of "very much better" or "much better" on the PGI-I. Assuming a PGI-I response of "improved" in 66% of placebo and 93% of onabotulinumtoxinA participants, 68 women were needed to show a significant difference with 80% power at 0.05 significance level. RESULTS: From March 2016 to November 2019, 78 women completed a 3-month follow-up (onabotulinumtoxinA: 41; placebo: 37). Mean age was 51 years (±10). On the PGI-I, the number who "improved" did not differ between groups at 3 months (83% vs 84%, P=1.0). The onabotulinumtoxinA group had less severe urgency symptoms as indicated by median urgency PGI-S scores (1 [interquartile range 1-2] vs 2 [interquartile range 1-3], P=.033) and greater improvement in urgency symptoms based on median urgency PGI-I score (1 [interquartile range 1-3] vs 2 [interquartile range 2-4], P=.028). At 3 months, median UDI-6, PFIQ-7, and PGI-S scores improved significantly from baseline in both groups. Similarly, UDI-6 and PFIQ-7 scores did not differ between groups. More women in the onabotulinumtoxinA arm initiated intermittent self-catheterization, (3% placebo; 12% onabotulinumtoxinA, P=.20) and experienced urinary tract infections (5% placebo; 22% onabotulinumtoxinA, P=.051), but these did not differ statistically. CONCLUSION: Concurrent intradetrusor onabotulinumtoxinA injection did not improve overall incontinence symptoms at 3 months compared with placebo among women with mixed urinary incontinence undergoing midurethral sling placement. Women with mixed urinary incontinence undergoing sling report significant improvement in overall incontinence symptoms, regardless of the addition of onabotulinumtoxinA injections, but those receiving concurrent onabotulinumtoxinA injections reported less urgency severity and greater improvement in urgency symptoms at 3 months. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02678377.