The triglyceride-glucose index as a biomarker of diabetic retinopathy: A systematic review and meta-analysis.

This project presents a systematic review and meta-analysis investigating the association between the triglyceride-glucose (TyG) index—a surrogate marker of insulin resistance—and the presence and severity of diabetic retinopathy (DR). The study aims to synthesize existing evidence from observational studies, including cross-sectional, cohort, and case–control designs, to clarify whether elevated TyG levels are associated with an increased risk of DR in individuals with diabetes mellitus. The protocol was preregistered on PROSPERO (CRD420251110467) and follows PRISMA 2020 guidelines. Comprehensive database searches were performed in PubMed, Scopus, and Web of Science, and risk of bias was assessed using validated tools (AHRQ checklist for cross-sectional studies and Newcastle-Ottawa Scale). Meta-analytic techniques were used to pool effect sizes, evaluate heterogeneity, and assess publication bias. Subgroup analyses explored the influence of study design, diabetes type, and geographic region.The expected outcomes include pooled odds ratios or risk estimates for DR based on TyG index categories or continuous levels, identification of sources of heterogeneity, and evaluation of the predictive potential of the TyG index. This project aims to provide clinicians and researchers with a clearer understanding of the TyG index as a potential biomarker for microvascular complications, specifically diabetic retinopathy.\n\nAll data extraction forms, statistical code, risk of bias assessments, and figures are made available here to enhance reproducibility and transparency.