Combined effect of the triglyceride-glucose index and frailty index on advanced stages among cardiovascular-kidney-metabolic syndrome patients

Background Advanced cardiovascular-kidney-metabolic (CKM) syndrome (stages 3–4) signifies high-risk multi-organ dysfunction. The triglyceride-glucose-frailty index (TyG-FI), combining the TyG index with a frailty index, may better reflect both metabolic dysregulation and physiological decline than TyG-related indices alone. This study aimed to examine the association between TyG-FI and advanced CKM syndrome. Methods This cross-sectional analysis used 2011-March 2020 National Health and Nutrition Examination Survey data from 6,960 adults with CKM syndrome. CKM syndrome stages 3 or 4 were considered advanced. Survey-weighted logistic regression and restricted cubic splines models were used to evaluate the relationship between TyG-FI and advanced CKM syndrome. The discriminatory power of TyG-FI was assessed using receiver operating characteristic (ROC) curves and compared to other TyG-related indices and FI. Results The highest TyG-FI quartile had significantly increased odds of advanced CKM syndrome (odds ratio: 10.32, 95% confidence intervals: 6.51–16.34) versus the lowest. A unit increase in TyG-FI corresponded to an odds ratio of 2.78 (95% confidence intervals: 2.39–3.22). Restricted cubic splines indicated a nonlinear dose-response association between TyG-FI and advanced CKM syndrome. Furthermore, ROC analysis demonstrated that TyG-FI had superior discriminatory ability (AUC = 0.796) compared to FI and all other TyG-related indices. Conclusions TyG-FI shows a strong, dose-response association with advanced CKM syndrome and superior predictive performance, suggesting that a higher TyG-FI may increase the risk of advanced CKM syndrome.