The triglyceride-glucose index as a surrogate marker of insulin resistance for predicting peripheral vascular complications in patients with type 2 diabetes: A retrospective analysis

The TyG index, a simple surrogate marker for insulin resistance, shows promise for predicting vascular complications in T2DM. This study evaluated its utility in predicting peripheral vascular complications and analyzed the dose-response relationship. A retrospective analysis included 186 T2DM patients admitted between April and December 2025. Participants were categorized into a complications group (n = 66) and a no-complications group (n = 120). The TyG index was calculated and divided into quartiles. Multivariate logistic regression identified risk factors. RCS curves assessed the dose-response relationship, and ROC curves evaluated predictive value. The complications group was significantly older with longer diabetes duration. They exhibited higher fasting glucose, triglycerides, TyG index, cystatin C, urea, and creatinine levels (all P < .05), but lower HDL-C, albumin, eGFR, and hemoglobin levels (all P < .05). Prevalence of peripheral vascular disease increased progressively across TyG quartiles (Q1: 8.7%, Q2: 23.9%, Q3: 41.3%, Q4: 68.1%; P < .001). Multivariate analysis, using Q1 as reference, showed significantly elevated risks for complications: Q2 (OR = 2.24, 95% CI: 1.02-1.58, P = .046), Q3 (OR = 2.89, 95% CI: 1.34-4.31, P < .001), and Q4 (OR = 4.47, 95% CI: 2.42-6.58, P < .001). RCS analysis confirmed a significant nonlinear positive correlation between TyG index and complication risk (P for nonlinearity < .001). ROC analysis demonstrated the TyG index predicted complications with an AUC of 0.768 (95% CI: 0.698-0.838). The optimal cutoff value was 8.89, yielding 75.8% sensitivity and 70.8% specificity. The TyG index exhibits a significant nonlinear positive cross-sectional association with peripheral vascular complications in T2DM patients. While these findings suggest the potential utility of the TyG index as a marker for identifying existing peripheral vascular complications, larger multicenter prospective studies with external validation are needed before clinical implementation can be recommended.