Association between triglyceride-glucose index and diabetic kidney disease in adults with type 1 diabetes

BACKGROUND: Diabetic kidney disease (DKD) is a major microvascular complication of type 1 diabetes mellitus (T1DM) and is associated with insulin resistance (IR). The triglyceride glucose (TyG) index has been identified as an alternative marker of IR. This study aimed to investigate the association between the TyG index and DKD in in adult patients with T1DM. METHODS: A retrospective analysis was conducted on 210 adult patients with T1DM who were admitted to a single center between January 2021 and August 2025. The patients were divided into a non-DKD group (n = 150) and a DKD group (n = 60). They were further categorized into three groups according to tertiles of the TyG index. Demographic characteristics and biochemical parameters were collected and analyzed. Correlation analysis, logistic regression analysis, and receiver operating characteristic (ROC) curve analysis were performed. The calibration curve and decision curve analysis (DCA) were used to evaluate the accuracy and clinical utility. RESULTS: Patients with DKD had significantly higher TyG values than those without DKD and were more likely to present with chronic diabetic complications and comorbidities (P < 0.05). After adjusting for confounding factors, the TyG index was positively correlated with the urinary albumin-to-creatinine ratio (UACR, r = 0.202, P < 0.05) and negatively correlated with the estimated glomerular filtration rate (eGFR, r = − 0.190, P < 0.05). Logistic regression analysis showed that in Model 3, compared with the T1 group, the odds ratio (OR) for DKD in the T3 group was 2.248 (95% CI: 1.390–3.635, P = 0.001). ROC curve analysis demonstrated that the area under the curve (AUC) for the TyG index was 0.682 (95% CI: 0.605–0.758, P < 0.001), with a sensitivity of 0.750 and a specificity of 0.681. In comparison, the AUCs for the estimated glucose disposal rate (eGDR) and HbA1c was 0.554 (95% CI: 0.467–0.641, P = 0.235) and 0.586 (95% CI: 0.500–0.672, P = 0.059), respectively. DCA confirmed the clinical practicality of TyG model. CONCLUSION: The TyG index demonstrated a positive association with DKD in patients with T1DM and may serve as an adjunctive marker for early risk stratification or as a component of a multi-marker panel, rather than as a standalone diagnostic tool for DKD. CLINICAL TRIAL NUMBER: Not applicable.