Age-adjusted visceral adiposity index as a predictor of chronic kidney disease: insights from NHANES 2007–2018

The age-adjusted visceral adiposity index (AVAI) is a novel marker reflecting visceral fat-related metabolic risk. However, its relationship with chronic kidney disease (CKD) remains unclear. This study aims to evaluate the association between AVAI and CKD prevalence in U.S. adults. We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018, including 7,760 participants aged 20 years and older. Logistic regression models were used to examine the association between AVAI and CKD, with adjustments for demographic, lifestyle, and clinical factors. Restricted cubic spline and threshold effect analyses were applied to explore the potential nonlinear patterns, and subgroup analyses assessed the potential effect modifiers. Receiver operating characteristic (ROC) curves compared the predictive performance of AVAI and the traditional visceral adiposity index (VAI). AVAI was significantly associated with higher CKD prevalence after adjustment, with each 1-unit increase corresponding to a 47% higher risk of CKD (OR = 1.47, 95% CI: 1.36-1.59). A nonlinear association was observed, with a threshold at AVAI = -6.5, beyond which CKD risk increased steeply. Subgroup analysis showed a stronger association in older adults. ROC analysis indicated that AVAI had better discriminatory ability for CKD (AUC = 0.7581) than VAI (AUC = 0.5685). These findings suggest that AVAI is a promising, practical tool for identifying individuals at high risk of CKD in the general population.