Association between cardiometabolic index and prevalent cardiovascular disease among adults with hypertension: a cross-sectional study using two nationally representative surveys

The relationship between cardiometabolic index (CMI) and prevalent cardiovascular disease (CVD) among adults with hypertension remains unclear, and whether this association is consistent across different national settings requires further investigation. Therefore, this study aimed to examine the association between CMI and prevalent CVD among adults with hypertension using nationally representative data from the United States and China. In this study, we used data from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018 and the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to conduct cross-sectional analyses including 4,487 and 3,944 adults with hypertension, respectively. Survey weights and the corresponding complex sampling designs were incorporated into descriptive and regression analyses. Multivariable logistic regression models were used to evaluate the association of CMI with prevalent CVD. Multicollinearity was assessed using weighted variance inflation factors (VIFs) for CMI and all covariates included in the fully adjusted model. Restricted cubic spline (RCS) analyses were performed to assess potential nonlinear associations, and exploratory two-piecewise logistic regression was used to investigate potential threshold effects. Subgroup analyses were conducted according to age, sex, smoking status, and diabetes status, with interaction testing and correction for multiple testing. Multiple sensitivity analyses were performed to assess the consistency of the findings. In NHANES, higher CMI was associated with greater odds of prevalent CVD in the fully adjusted model (OR = 1.23, 95% CI: 1.04–1.46). Participants in the highest CMI quartile also had higher odds of prevalent CVD than those in the lowest quartile (OR = 1.85, 95% CI: 1.37–2.50). In CHARLS, the association was attenuated after full adjustment (OR = 1.08, 95% CI: 0.99–1.18), although a positive trend across CMI quartiles remained evident ( P for trend = 0.0194). All VIFs were below 2, indicating no evidence of substantial multicollinearity. RCS analyses showed no significant evidence of nonlinearity for prevalent CVD in NHANES ( P for nonlinear = 0.0773), whereas a nonlinear association was observed in CHARLS ( P for nonlinear = 0.0408). Exploratory threshold analyses suggested threshold related changes in the association between CMI and CVD. In exploratory subgroup analyses, nominal age-related heterogeneity was observed for CVD, ASCVD, and CHF in NHANES, with stronger associations among participants aged ≥ 60 years. Sensitivity analyses generally yielded directionally consistent results. Higher CMI was associated with greater odds of prevalent CVD among adults with hypertension in two nationally representative surveys. These findings suggest that CMI may reflect a greater burden of prevalent CVD in hypertensive populations. Not applicable.