A Randomized Noninferiority Trial of Retropubic KIM Sling vs TVT Exact Sling for Stress Urinary Incontinence: One-Year Outcomes

INTRODUCTION: Medical waste can be reduced by utilizing the Neomedic Knotless Incontinence Mesh (KIM) sling with sterilizable, reusable trocars compared to those with disposable trocars. Our initial investigation of comparative effectiveness at 6 weeks was inconclusive. OBJECTIVE: To determine whether the KIM sling is noninferior to the TVT Exact sling at 1 year for treatment of stress urinary incontinence (SUI). METHODS: This was a single-center, randomized noninferiority trial comparing the outcomes of two retropubic slings, KIM vs TVT Exact, for treatment of SUI from August 2021 to June 2024. The primary outcome was effectiveness at 1 year defined by a composite outcome of a negative response to the question #17 on the PFDI-20 and no SUI retreatment. Secondary outcomes included rates of mesh exposure, urinary retention, and reoperation for mesh complications. For our sample size, we needed 72 per group based on a noninferiority margin of 14%, equal effectiveness of 90%, alpha 0.05, and 80% power with a 20% dropout. RESULTS: Among 147 participants, 73 (49.7%) were randomized to TVT Exact vs 74 (50.3%) to KIM. Baseline demographics were similar between the two groups; participants were predominantly older (58 for TVT Exact vs 59.7 for KIM, p=0.42), White (86.3% for TVT Exact vs 83.8% for KIM, p=0.67) nonsmokers (12.3% for TVT Exact vs 13.5% for KIM, p=0.83) with similar rates of stage III–IV prolapse (35.6% for TVT Exact vs 28.4% for KIM, p=0.30) and similar rates of prior hysterectomy (30.1% for TVT Exact vs 27.0% for KIM, p=0.68). There was a higher rate of concomitant anterior repair in the KIM group vs the TVT Exact group (38.4% for TVT Exact vs 56.8% for KIM, p=0.03). One-year validated questionnaires were completed by 138 (93%) participants, and 106 (72%) completed an in-person visit. Effectiveness at 1 year was 82.1% for the TVT Exact group vs 74.6% for the KIM group, with a risk difference of 7.4% (95% CI, −6.2, 21.1). Given that the 95% upper confidence limit was outside of the 14% noninferiority margin, noninferiority was unable to be demonstrated (Figure 1). For secondary outcomes, the rates of mesh exposure at 1 year were 11.1% (n=6) in the TVT Exact group vs 1.9% (n=1) in the KIM group (p=.11). Additional secondary outcomes are displayed in Table 1. CONCLUSIONS: The KIM sling is not noninferior to the TVT Exact sling for the treatment of SUI at 1 year based on a composite outcome score.