Leaks After Sleeve Gastrectomy: An Umbrella Review of Systematic Reviews and Meta-Analyses v1

Background: Sleeve gastrectomy has become one of the most commonly performed bariatric procedures worldwide. Despite its popularity, staple line leaks remain a serious and potentially life-threatening complication. Multiple systematic reviews and meta-analyses have examined leak rates, risk factors, and management strategies, but findings vary across reviews. A comprehensive synthesis of this high-level evidence is needed to guide clinical practice and identify research gaps. Objective: To systematically identify, critically appraise, and synthesize all existing systematic reviews and meta-analyses examining leak incidence, risk factors, timing, and management outcomes following sleeve gastrectomy. Methods: This umbrella review will follow the PRISMA 2020 guidelines. We will conduct comprehensive searches in PubMed and Google Scholar from inception to present. Two independent reviewers will screen titles, abstracts, and full-text articles using predefined eligibility criteria. Eligible studies will include systematic reviews (with or without meta-analysis) that report leak rates following sleeve gastrectomy in adult patients. We will extract data on review characteristics, search methodology, leak incidence, timing, risk factors, and management outcomes. Methodological quality will be assessed using AMSTAR-2 (A MeaSurement Tool to Assess systematic Reviews). Primary study overlap will be quantified using the GROOVE (Graphical Representation of Overlap for OVErviews) and presented in a citation matrix. If appropriate, we will conduct umbrella meta-analysis using random-effects models to estimate pooled leak rates with 95% confidence intervals. Subgroup analyses will examine leak rates by geographic region, timing (early vs. late), surgical approach, and temporal trends. Sensitivity analyses will assess the robustness of findings by excluding low-quality reviews and high-overlap studies. The certainty of evidence will be assessed using the GRADE approach for key outcomes. Expected Outcomes: This umbrella review will provide a comprehensive synthesis of the highest-level evidence on leaks following sleeve gastrectomy, including pooled leak incidence rates, identification of key risk factors, characterization of leak timing patterns, and evaluation of management strategies. We will assess the methodological quality of existing systematic reviews, quantify the degree of primary study overlap, and identify gaps in the current evidence base. Clinical and Research Implications: The findings will inform clinical decision-making regarding patient selection, surgical technique optimization, and early detection strategies. By identifying methodological limitations and evidence gaps, this review will guide the design of future primary studies and systematic reviews. The assessment of primary study overlap will help prevent double-counting in future evidence syntheses and meta-analyses. Protocol Registration: This protocol will be registered with protocols.io prior to commencing the systematic search. Keywords: Sleeve gastrectomy; vertical sleeve gastrectomy; gastric leak; staple line leak; anastomotic leak; umbrella review; overview of systematic reviews; bariatric surgery; complications; meta-analysis.