The Effect of Midurethral Slings on Overactive Bladder in Women With Mixed Urinary Incontinence

INTRODUCTION: Mixed urinary incontinence (MUI), defined as having both stress (SUI) and urge urinary incontinence (UUI), can greatly impair quality of life. Midurethral sling (MUS) procedures are an effective treatment for the stress component of MUI, but improvement rates for the urge component can be variable. Level 1 evidence provided by the ESTEEM trial indicated MUS can effectively cure SUI and improve overactive bladder/urge urinary incontinence (OAB/UUI) symptoms. Our study from a single academic institution can also be used to assess the clinical outcomes of patients with MUI who underwent MUS procedures. OBJECTIVE: The objective of this study was to evaluate the effectiveness of MUS in patients diagnosed with MUI and whether MUS was able to reduce the need for further OAB treatment. METHODS: In this retrospective cohort study, electronic medical records of patients with MUI who underwent MUS placement at a single academic institution from 2017 to 2023 were reviewed. Data, which included demographics and important pelvic floor and urinary continence parameters, were used to evaluate the postoperative use of OAB medication or other OAB treatments among women who were and were not on OAB medications preoperatively and compared them with respect to their use of OAB medications or other treatments postoperatively. Minimum follow-up was 6 months. The t-test was used for continuous variables, a chi-square test was used for categorical variables, and also a one-way ANOVA was used. RESULTS: Of the total of 617 patients who had MUI, 502 (81.4%) were not on OAB medications preoperatively. Among those 502 women, 74 (14.7%) needed medication postoperatively, while 428 (85.2%) did not. There were 114 (18.6%) patients who were taking OAB medication prior to MUS placement. Of those, 72 (63.2%) continued the same medication, 14 (12.3%) needed to change their OAB medication, increase the dose, or step up to third-line therapies such as Botulinum A or sacral nerve modulation, and 29 (25.4%) no longer required medication. Baseline characteristics were similar between women who were not on medication prior to MUS but started medication postoperatively and those who did not, except for age. Of the group that were not on OAB medication preoperatively, the women who started postoperatively were younger (56.6+11.0 vs 60.2+12.7 p=0.03). Among 114 women who were already taking medication preoperatively, women who discontinued the medication were younger (58.9 +13.3 vs 51.8+14.3, p=0.06), but all other characteristics were similar between them and those who continued or escalated OAB treatment. Importantly, SUI remained as a persistent symptom in 23 (4.7%) women. This rate was low in all groups, without any difference among them. CONCLUSIONS: This retrospective study demonstrates that MUS procedures are effective treatment for patients with MUI. Overall, the majority of patients who were taking medication for OAB/UUI continued to do so, and those who did not prior to the MUS continued without medication. Further studies are warranted to explore long-term outcomes and refine patient selection criteria about when to stop or resume OAB treatment in women with MUI who undergo MUS procedures (Table 1).