Abstract
BACKGROUND: Although dietary patterns are recognized as modifiable risk factors for chronic kidney disease (CKD), comparative evidence on the differential impacts of commonly used dietary indices remains limited. This study aims to evaluate associations between four indices (Healthy Eating Index-2020, HEI-2020; alternative Mediterranean Diet Score, aMED; Dietary Approaches to Stop Hypertension, DASH; Dietary Inflammatory Index, DII) and CKD risk, and explore their population heterogeneity. METHODS: Utilizing cross-sectional data from NHANES (2000-2020), dietary scores were calculated for individuals with or without CKD. Logistic regressions estimated normalized odds ratio (ORs) per 25% scoring range increase. Predictive utility was assessed via marginal receiver operating characteristic (ROC) curves, and nonlinear associations were detected using restricted cubic splines (RCS). Subgroup analyses were conducted across different population characteristics. Component analyses were used to evaluate which components within each dietary index exert a significant effect on CKD risk. RESULTS: DASH (OR = 0.880, 95%CI: 0.812-0.954) and DII (OR = 1.099, 95%CI: 1.025-1.180) were significantly associated with CKD risk, only DII remained associated with CKD severity progression (OR = 1.264, 95%CI: 1.103-1.450). Dietary indices provided incremental utility second to comorbidities and age. Nonlinear analyses revealed that greater adherence to DASH/DII reduced CKD risk, with consistent results across subgroups of males, individuals over 65 years, Non-Hispanic Whites, both smokers and nonsmokers, family income-to-poverty ratio >3.5, and individuals with hypertension or without diabetes and cardiovascular diseases. CONCLUSIONS: DASH and DII exhibited superior CKD risk discrimination versus other indices. Adopting dietary habits aligned with DASH/DII was most effective for reducing CKD risk in dietary interventions.