Association between weight-adjusted waist index and cardiovascular diseases in prediabetic and diabetic patients in the United States: a cross-sectional study

To examine the association between weight-adjusted waist index (WWI) and cardiovascular diseases (CVD) in prediabetic and diabetic patients in the United States. This cross-sectional study included 18,007 participants from the National Health and Nutrition Examination Survey (NHANES) 2003–2018. WWI was calculated as waist circumference divided by the square root of weight. CVD outcomes were defined based on self-reported physician diagnoses and standardized criteria. Weighted multivariate logistic regression and smoothed fit curves to assess the association between WWI and CVD in prediabetic and diabetic adults. The discriminatory ability and calibration of the models were evaluated using receiver operating characteristic (ROC) curves and calibration plots, respectively, as secondary analyses to explore the potential predictive utility of WWI. Subgroup analyses with Benjamini–Hochberg correction for multiple comparisons were conducted to examine the moderating effects of covariates and to assess the stability of the results. In the fully adjusted categorical model, the highest WWI tertile (T3) was associated with significantly higher odds of CVD compared with the lowest tertile (T1): hypertension (odds ratio [OR]: 2.17, 95% confidence interval [CI]: 1.91–2.45); coronary heart disease (OR: 1.64, 95%CI: 1.22–2.21); stroke (OR: 1.90, 95%CI: 1.39–2.59); heart failure (OR: 1.97, 95%CI: 1.47–2.64); angina (OR: 1.72, 95%CI: 1.27–2.31); and myocardial infarction (OR: 1.95, 95%CI: 1.46–2.59). Smoothed fit curves confirmed a positive association. ROC analysis showed acceptable discrimination for all CVD outcomes (AUC: 0.715–0.778), and calibration curves indicated good agreement. In subgroup analyses, after adjusting for multiple comparisons, the interaction between age and WWI for myocardial infarction remained statistically significant (adjusted p = 0.042). Higher WWI was positively associated with increased odds of CVD in pre­diabetic and diabetic patients in the United States, with acceptable model discrimination and calibration.