Male Urinary Incontinence Severity and Non-Adjustable Sling Outcomes: Protocol for a Multivariate Dose-Response Meta-Analysis

Background and Objective: Male stress urinary incontinence (UI), particularly after radical prostatectomy, remains a clinically relevant condition with a detrimental impact on patients’ quality of life. Non-adjustable male slings are widely used for the treatment of this condition. Although baseline UI severity is an established predictor of sling outcomes, the true relationship between UI severity and sling efficacy remains unknown. This protocol describes a systematic review with dose–response meta-analysis designed to investigate the association between UI severity and the outcomes of non-adjustable slings. Methods: A comprehensive literature search will be conducted in MEDLINE (PubMed), Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials from database inception. Eligible studies will include randomized controlled trials and observational studies enrolling adult men undergoing sling surgery, with at least six months of follow-up. UI severity must be measured preoperatively using objective metrics and reported across at least two severity categories. The primary outcomes will be failure to achieve cure or failure to achieve overall success defined as cure or clinically meaningful improvement. Study quality will be assessed using the QUIPS tool. Dose–response relationships will be analyzed using advanced meta-analytic methods, allowing assessment of both linear and nonlinear associations. Potential sources of heterogeneity will be explored through subgroup analyses and meta-regression. The robustness of the findings will be evaluated through sensitivity analyses and assessment of publication bias. Finally, the certainty of evidence will be graded using the GRADE framework. We will adhere to the PRISMA recommendations in the reporting of this review. Conclusions: This analysis will provide quantitative evidence to improve patient selection, refine counseling, and support evidence-based decision-making in the surgical management of male stress UI.