The Triglyceride-Glucose Index and Risk of End-Stage Renal Disease across Different Durations of Type 2 Diabetes Mellitus: A Longitudinal Cohort Study

Background: This study investigated the association between the triglyceride-glucose (TyG) index, a marker of insulin resistance, and the risk of end-stage renal disease (ESRD) in individuals with type 2 diabetes mellitus (T2DM), focusing on variations by diabetes duration. Methods: We analyzed 1,219,148 Korean adults with T2DM from National Health Insurance Service data who underwent biennial health evaluations (2015 to 2016). ESRD was defined using specific procedural codes (V codes), and Cox proportional hazard models were employed to estimate hazard ratios (HRs) for ESRD across TyG index quartiles and diabetes duration categories, adjusting for various confounders. Results: Over 6,967,381 person-years of follow-up, 7,548 participants developed ESRD. Higher TyG index quartiles were independently associated with increased risk of ESRD, which was more pronounced with longer diabetes duration. The adjusted HR for ESRD in the highest TyG quartile (Q4) compared to the lowest quartile (Q1) was 1.235 (95% confidence interval [CI], 0.995 to 1.533) in new-onset diabetes, and 1.592 (95% CI, 1.465 to 1.730) in those with diabetes for ≥10 years. Compared to the lowest TyG quartile in new-onset diabetes, the adjusted HR for ESRD in the highest quartile with diabetes duration ≥10 years increased to 10.239 (95% CI, 8.440 to 12.422). Subgroup analysis revealed that a higher TyG index consistently increased the risk of ESRD, with stronger associations observed in younger individuals and those without comorbidities. Conclusion: The TyG index is a significant predictor of ESRD in T2DM, particularly in those with prolonged diabetes duration. Targeting insulin resistance early may mitigate the risk of ESRD in this population.