Insulin resistance related indices are associated with the presence of Cardiorenal syndrome: insights from NHANES 2005-2020

Background Cardiorenal syndrome (CRS) is a complex and severe clinical condition that is gaining increasing attention. Previous studies indicate that insulin resistance (IR) strongly correlates with cardiac diseases (e.g., coronary artery disease, heart failure) and renal disorders (e.g., diabetic nephropathy, chronic kidney disease), with its metrics serving as predictors for cardiovascular and renal risks. However, the concurrent impact of insulin resistance on both organs and its relationship with CRS remain unclear. This study investigates associations between three novel insulin resistance indicators and CRS. Methods This cross-sectional study utilized data from 14,947 participants in the 2005–2020 of the U.S. National Health and Nutrition Examination Survey (NHANES). CRS was defined as coexisting cardiovascular disease and chronic kidney disease (estimated glomerular filtration rate < 60 mL/min/1.73 m²). Three insulin resistance indices were evaluated: estimated glucose disposal rate (eGDR), metabolic insulin resistance score (METS-IR), and triglyceride-glucose index (TyG). Multivariable weighted logistic regression models calculated odds ratios (ORs) and 95% confidence intervals (CIs) for CRS associations. Restricted cubic spline curves assessed nonlinear relationships, while receiver operating characteristic (ROC) analyses evaluated the predictive capacity of these indices for CRS. Results CRS was present in 3.04% of participants. After full covariate adjustment, per standard deviation (SD) increase in eGDR was negatively associated with the presence of CRS (adjusted OR = 0.73, 95% CI: 0.66–0.77); each SD increase in METS-IR was positively associated with the presence of CRS (adjusted OR = 3.62, 95% CI: 2.11–6.20). In contrast, TyG showed no significant association with CRS in fully adjusted models. Subgroup analyses revealed that the associations of eGDR and METS-IR with CRS remained stable across all subgroups. Notably, among the three variables, eGDR had the strongest diagnostic value for CRS (AUC = 0.758). Conclusions Of the three IR indices, eGDR and METS-IR were significantly associated with the presence of patients with CRS. Furthermore, eGDR demonstrated a good predictive value for CRS. Collectively, these findings suggest that eGDR may be a stronger marker of CRS.