Red cell distribution width is independently related to endothelial dysfunction in patients with chronic kidney disease.

BACKGROUND: Red cell distribution width (RDW) is a measure of erythrocyte size variability and has been shown as an independent predictor of mortality. The aim of this article was to evaluate the association of RDW with endothelial dysfunction in patients with chronic kidney disease (CKD).

METHODS: Patients with 1 to 5 stages of CKD were included in the study. Endothelial function was assessed with flow-mediated dilatation (FMD). Estimated glomerular filtration rate (eGFR) and carotid intima media thickness (CIMT) were determined. Clinicodemographic characteristics, biochemical values, complete blood counts, ferritin, C-reactive protein (CRP) and cholesterol levels were recorded. Spearman's correlation was used to determine correlates of RDW. Multivariate linear regression model was used to assess independent associates of FMD.

RESULTS: Overall, 367 patients with CKD 1 to 5 were included in the study. RDW showed a significant increase from stage 1 to stage 5 CKD. Median RDW was 13.5. Patients with RDW values higher than median had significantly lower hemoglobin, eGFR and FMD values and higher CIMT and CRP values compared with patients who had RDW values below median. RDW showed a significant positive correlation with the presence of diabetes mellitus, CIMT and CRP, whereas a significant negative correlation with eGFR, ferritin and FMD. Multivariate analysis showed independent predictors of FMD as RDW, presence of diabetes, hemoglobin, eGFR, CRP, and serum albumin.

CONCLUSIONS: Multivariate regression model revealed RDW as a significant predictor of FMD independent of major confounding factors, such as diabetes, inflammation, anemia and kidney function in CKD.