ObjectiveThis study aimed to evaluate the associations and discriminative performance of TyG-derived composite indices compared to the cholesterol-HDL-C-glucose (CHG) index system for frailty.MethodsIn this cross-sectional study, we examined five consecutive cycles (2009-2018) of the National Health and Nutrition Examination Survey. After excluding participants with incomplete data, 10,311 adults were included. We calculated TyG, CHG, and their adiposity-adjusted composite indices. To assess associations with frailty, we used multivariable logistic regression and applied restricted cubic splines to evaluate potential nonlinearity. Discriminative performance was assessed using receiver operating characteristic curves, with AUC values compared using paired DeLong tests. Incremental discrimination analyses using ΔAUC and net reclassification improvement (NRI) were also performed.ResultsIn fully adjusted models, both higher TyG-derived indices and the CHG index system (along with its composite indices) were consistently associated with increased odds of frailty. Among all indices, body-roundness-related composites demonstrated the best discrimination. Specifically, TyG-BRI (AUC 0.706) and CHG-BRI (AUC 0.700) outperformed their individual metabolic markers, TyG (AUC 0.630) and CHG (AUC 0.588), respectively, indicating moderate overall discriminative ability. Incremental discrimination analyses demonstrated that TyG-BRI and CHG-BRI offered enhanced discriminative value compared to their respective base metabolic markers. Sensitivity analyses confirmed the robustness of these findings.ConclusionsTyG- and CHG-derived composite indices, particularly TyG-BRI and CHG-BRI, were positively associated with frailty. They demonstrated moderate discriminative performance and superior ability compared to individual metabolic markers for identifying prevalent frailty. However, due to the cross-sectional nature of NHANES, these indices should be regarded as adjunctive markers rather than stand-alone frailty screening tools. Prospective studies are required to further assess their potential adjunctive clinical value.
Keywords: CHG index; NHANES; TyG index; body fat distribution; frailty.