The SIMS trial: adjustable anchored single-incision mini-slings versus standard tension-free midurethral slings in the surgical management of female stress urinary incontinence. A study protocol for a pragmatic, multicentre, non-inferiority randomised controlled trial.

INTRODUCTION: Single-incision mini-slings (SIMS) represent the third generation of midurethral slings. They have been developed with the aim of offering a true ambulatory procedure for treatment of female stress urinary incontinence (SUI) with reduced morbidity and earlier recovery while maintaining similar efficacy to standard midurethral slings (SMUS). The aim of this study is to determine the clinical and cost-effectiveness of adjustable anchored SIMS compared with tension-free SMUS in the surgical management of female SUI, with 3-year follow-up.

METHODS AND ANALYSIS: A pragmatic, multicentre, non-inferiority randomised controlled trial.

PRIMARY OUTCOME MEASURE: The primary outcome measure is the patient-reported success rate measured by the Patient Global Impression of Improvement at 12 months. The primary economic outcome will be incremental cost per quality-adjusted life year gained at 12 months.

SECONDARY OUTCOME MEASURES: The secondary outcomes measures include adverse events, objective success rates, impact on other lower urinary tract symptoms, health-related quality of life profile and sexual function, and reoperation rates for SUI. Secondary economic outcomes include National Health Service and patient primary and secondary care resource use and costs, incremental cost-effectiveness and incremental net benefit.

STATISTICAL ANALYSIS: The statistical analysis of the primary outcome will be by intention-to-treat and also a per-protocol analysis. Results will be displayed as estimates and 95% CIs. CIs around observed differences will then be compared with the prespecified non-inferiority margin. Secondary outcomes will be analysed similarly.

ETHICS AND DISSEMINATION: The North of Scotland Research Ethics Committee has approved this study (13/NS/0143). The dissemination plans include HTA monograph, presentation at international scientific meetings and publications in high-impact, open-access journals. The results will be included in the updates of the National Institute for Health and Care Excellence and the European Association of Urology guidelines; these two specific guidelines directly influence practice in the UK and worldwide specialists, respectively. In addition, plain English-language summary of the main findings/results will be presented for relevant patient organisations.

TRIAL REGISTRATION NUMBER: ISRCTN93264234. The SIMS study is currently recruiting in 20 UK research centres. The first patient was randomised on 4 February 2014, with follow-up to be completed at the end of February 2020.