Weight-adjusted waist index and risk of cardiovascular and all-cause mortality in chronic kidney disease: NHANES 2005–2018 analysis of 5,381 adults

Central adiposity is a key driver of cardiovascular risk in chronic kidney disease (CKD), yet conventional obesity indices incompletely capture this risk. The weight-adjusted waist index (WWI) is an emerging anthropometric measure that integrates abdominal adiposity independent of body weight, but its prognostic relevance in CKD remains unclear. This prospective cohort study utilized data from the National Health and Nutrition Examination Survey (NHANES 2005-2018) and the National Death Index. Over a median follow-up of 79 months, higher WWI quartiles were associated with progressively increased risks of CVD (highest vs. lowest quartile OR: 1.81, 95% CI: 1.39-2.34) and mortality (CVD HR: 1.73, 95% CI: 1.15-2.60; all-cause HR: 1.45, 95% CI: 1.22-1.72) among 5,381 participants. Subgroup and sensitivity analyses further confirmed the robustness of these findings. Mediation analysis revealed that both the neutrophil-to-lymphocyte ratio and the systemic inflammation response index significantly mediated the associations between WWI and all-cause mortality, as well as between WWI and CVD-specific mortality. In fully adjusted Model 2, receiver operating characteristic curve analysis showed area under the curve values for WWI in relation to CVD mortality and all-cause mortality of 0.793 and 0.763, respectively. WWI is a robust predictor of cardiovascular and all-cause mortality in U.S. adults with CKD, with systemic inflammation partially mediating this relationship. Incorporating WWI into CKD risk stratification may improve identification of high-risk cardio-kidney-metabolic phenotypes.