Association and Discriminative Performance of a Body Shape Index (ABSI) for Cardiometabolic Disease in a Korean Population

Background/Objectives: A body shape index (ABSI) has been proposed as an anthropometric measure reflecting abdominal body shape beyond body mass index (BMI). However, its relative cross-sectional discriminative ability compared with conventional anthropometric measures and surrogate markers of insulin resistance for prevalent diabetes and cardiovascular disease (CVD) remains poorly characterized in Korean adults. Methods: This cross-sectional study included 11,448 Korean adults aged 18–64 years from the 2019–2021 Korean National Health and Nutrition Examination Survey (KNHANES). Using receiver operating characteristic (ROC) curve analyses, we compared the discriminative ability of ABSI with BMI, waist circumference, waist-to-height ratio, homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride-to-HDL cholesterol ratio (TG/HDL-C), and the triglyceride–glucose index (TyG) for prevalent diabetes and CVD. Multivariable logistic regression analyses assessed associations after adjustment for demographic and socioeconomic factors. Results: ABSI showed the highest ROC-AUC for both prevalent diabetes (74%) and CVD (74%) among the compared indices. In multivariable-adjusted analyses, individuals in the very high ABSI risk group had higher odds of prevalent CVD (OR, 3.75; 95% CI, 1.60–8.78) than those in the very low-risk group. Among individuals with diabetes, the odds of comorbid CVD were also higher in the very high ABSI group (OR, 3.38; 95% CI, 2.26–5.07). Similar patterns appeared in obesity-subgroup analyses. Conclusions: ABSI showed greater discriminative ability for prevalent diabetes and CVD than several conventional measures and insulin-resistance markers, supporting its potential utility as a simple marker of cardiometabolic disease burden. Prospective studies are needed to determine its prognostic value.