Association between red blood cell distribution width-to-albumin ratio and chronic kidney disease: A cross-sectional study.

To investigate the association between red cell distribution width-to-albumin ratio (RAR) and chronic kidney disease (CKD) prevalence in the general adult population in the United States, where relevant evidence remains scarce. This cross-sectional study used data from the National Health and Nutrition Examination Survey spanning 2005 to 2018. Eligible participants were adults aged ≥ 20 years with complete data on RAR and CKD. Weighted multivariate logistic regression models, adjusted for demographics (age, sex, and race), lifestyle (smoking, alcohol consumption), metabolic indicators (body mass index, glucose, and lipids), and comorbidities (hypertension and diabetes) were used to assess the RAR-CKD association. Restricted cubic spline and subgroup analyses were performed to evaluate the nonlinearity and stability of the results, respectively. Receiver operating characteristic curve analysis was performed to determine the predictive ability of RAR for CKD. Among the 29,847 participants, a significant positive association was observed between higher RAR and increased CKD prevalence after full adjustment. Restricted cubic spline analysis confirmed a positive nonlinear relationship between the two. Subgroup analyses (stratified by sex, race, body mass index, and comorbidities) revealed heterogeneity in the strength of the association, while the positive direction remained consistent across all subgroups. Additionally, the receiver operating characteristic curve analysis demonstrated that RAR has a certain predictive ability for CKD. Elevated RAR is significantly associated with a higher prevalence of CKD in American adults. As an easily accessible biomarker reflecting integrated inflammatory and nutritional status, RAR holds the potential for early CKD risk assessment and the development of personalized management strategies.