Study design, materials and methods
We conducted a randomized, multi-center trial of MUS+BPTx vs. MUS alone for treatment of MUI. MUI was defined as at least moderately bothersome stress (SUI) and urgency (UUI) incontinence symptoms (based on the Urogenital Distress Inventory (UDI)), objective SUI, and ≥1 episode of both SUI and UUI on a 3-day bladder diary. Participants underwent retropubic or transobturator MUS. Randomization to BPTx was 1:1 and stratified by site and UUI severity. The BPTx intervention, conducted by trained interventionists, included a standardized intervention with education on voiding habits, pelvic floor muscle training, bladder training, strategies to control urgency and reduce/prevent urinary symptoms starting 1 month prior to and lasting 6 months after the MUS surgery.
The primary outcome was change in MUI symptoms 12 months post MUS based on the total UDI score, analyzed by intention to treat (ITT). Secondary outcomes included SUI and UUI symptoms based on UDI stress and irritative subscale scores, 3-day bladder diary, Patient Global Impression of Improvement and Severity (PGI-I, PGI-S), and the Incontinence Impact Questionnaire (IIQ). General linear mixed modeling, adjusting for site, visit, baseline UUI severity, and additional UI treatment post MUS, was used to compare efficacy of MUS+BPTx and MUS alone. The trial was powered to detect published minimum important differences between groups for the total UDI score, UDI-irritative, and UDI-stress subscale scores, yielding a sample size of 200 women per group. 472 were randomized to allow a 15% dropout.
464 participants were included in the primary analysis (235 MUS+BPTx, 229 MUS). Mean age was 54 (+/- 11) years, 78% were White, 9% Black/African American, and 23% Latina. Mean BMI was 32 (+/- 7). The MUS+BPTx group had a greater improvement in severity of total-UDI scores compared to the MUS alone group (-129 vs. -115 points, P=0.03). The UDI-irritative and UDI-stress subscale scores significantly improved, with the MUS+BPTx showing greater improvement (see Table). The MUS+BPTx group also had greater improvements in diary parameters, normalization of voiding frequency and IIQ scores compared to MUS alone (see Table). There was no difference in PGI-I or PGI-S scores between groups. At 12 months, MUS+BPTx decreased the risk of requesting any additional SUI or UUI treatment compared to MUS alone (aOR: 0.44 (0.24, 0.81)).
Interpretation of results
The MUS is associated with improvements in MUI symptoms at 12 months. The addition of BPTx improves UDI scores, the number of total and UUI episodes, urinary frequency, pad use and quality of life compared to MUS alone.