Red Cell Distribution Width to Albumin Ratio: A New Predictor of Mortality in Dialysis Patients with Coronary Artery Disease

Purpose: This study assessed the prognostic significance of the red cell distribution width to albumin ratio (RAR) in dialysis patients with coronary artery disease (CAD). Patients and methods: From January 2015 to June 2021, data from 1,128 dialysis patients with confirmed CAD from the CRUISE-R cohort (Coronary Revascularization in Patients on Dialysis in China-Retrospective)were analyzed. Patients were divided into three groups according to RAR tertiles: Tertile 1 (RAR ≤ 3.56), Tertile 2 (3.56 < RAR ≤ 4.13), and Tertile 3 (RAR > 4.13). The primary endpoints were all-cause and cardiovascular mortality, with secondary endpoints examining major adverse cardiovascular events (MACEs). Multivariate Cox regression models were used to evaluate the independent association between RAR and clinical outcomes. The improvement in the RAR's predictive performance was evaluated via continuous net reclassification improvement (NRI) and integrated discrimination improvement (IDI). Results: During a median follow-up of 20.9 months, the tertile 3 group presented the highest incidence rates for all-cause mortality, cardiovascular mortality, and MACE, with all comparisons being statistically significant (p<0.001 for all-cause and cardiovascular mortality, p=0.001 for MACE). Compared with the reference group, higher RAR levels were significantly associated with greater risks of all-cause mortality (HR, 1.592; 95% CI, 1.212–2.092) and cardiovascular mortality (HR, 1.503; 95% CI, 1.086–2.080). Restricted cubic spline (RCS) analysis revealed a linear relationship between RAR and all-cause mortality, cardiovascular mortality, and MACE, with all p values for nonlinearity being less than 0.05. Integrating RAR into the GRACE and Gensini models significantly increased the predictive accuracy for all-cause and cardiovascular mortality, as evidenced by notable improvements in NRI and IDI (all p≤0.001). Conclusion: An elevated RAR independently predicts poor outcomes in dialysis patients with CAD (ClinicalTrials.gov NCT05841082*). *The registration date for the Clinical Trial Number in the manuscript was 2020-12-28, and the clinical trial registry was the China-Japan Friendship Hospital.