Association between coronary heart disease and cardiometabolic index: a study from NHANES 1999–2018

BACKGROUND: The cardiometabolic index (CMI), a sex-specific marker combining lipid profiles with anthropometric measures, may reflect visceral adiposity dysfunction. Its association with coronary heart disease (CHD) risk remains inadequately characterized in large populations. METHODS: This cross-sectional study included 20,888 adults from the National Health and Nutrition Examination Survey (NHANES) 1999–2018. The association between CMI and CHD was assessed using weighted multivariable logistic regression. Restricted cubic splines (RCS) and threshold effect analyses explored non-linearity. A predictive model was developed and evaluated via receiver operating characteristic (ROC) analysis. RESULTS: After full adjustment, a significant positive association was observed between CMI and CHD risk (OR = 1.17, 95%CI:1.11–1.23). Participants in the highest CMI quartile had a 58% greater risk than those in the lowest (OR = 1.58, 95%CI:1.06–2.37). RCS analysis revealed a non-linear relationship (P-nonlinearity < 0.001), with a threshold identified at CMI = 1.175. Below this point, each unit increase in CMI was associated with a 133% elevation in CHD risk (OR = 2.33, 95%CI:1.83–2.97). The final predictive model, incorporating CMI and key covariates, demonstrated robust discrimination (AUC = 0.861, 95%CI:0.851–0.872). CONCLUSIONS: CMI is independently and non-linearly associated with CHD prevalence, with a heightened effect below a threshold of 1.175. This index shows promise as a practical tool for improving CHD risk stratification.