Prognostic value of RDW and its derivatives in ICU patients with hypertensive chronic kidney disease

Abstract

Chronic kidney disease (CKD) complicated with hypertension constitutes a major global public health burden. Early identification of reliable prognostic biomarkers is essential to optimize clinical management and reduce mortality among these patients. A total of 6,731 intensive care unit (ICU) patients with hypertensive CKD were enrolled from the MIMIC-IV database. Three hematological markers were analyzed: red blood cell distribution width (RDW), hemoglobin to RDW ratio (HRR), and RDW to platelet ratio (RPR). Cox regression, Kaplan-Meier, and restricted cubic spline analyses were used to evaluate associations with prognosis. ROC curves, C-index, NRI, and IDI assessed predictive performance and incremental value, and decision curve analysis (DCA) evaluated clinical net benefit. Subgroup and sensitivity analyses were also performed. Among 6,731 patients with hypertensive CKD, 2,505 (37.2%) died within one year. After multivariate adjustment, elevated RDW was associated with an increased risk of one-year all-cause mortality (HR = 1.19, 95% CI: 1.16–1.21, P < 0.001), while a higher HRR correlated with reduced mortality risk (HR = 0.89, 95% CI: 0.87–0.91, P < 0.001). The RPR showed a U-shaped correlation with one-year all-cause mortality. The areas under the ROCs for RDW, HRR and RPR were 0.668, 0.600 and 0.515, respectively. RDW and HRR can improve the predictive performance of conventional risk models, while the incremental value of RPR was heterogeneous and limited to specific scoring systems. DCA demonstrated that RDW, HRR, and RPR all provided favorable clinical net benefits across a wide range of high-risk thresholds, suggesting their potential clinical applicability. Subgroup analyses demonstrated significant interactions of RDW with CRRT use and CKD stage ( P < 0.001), as well as a notable interaction between HRR and CRRT ( P < 0.001). Sensitivity analysis verified the robustness of the present findings. RDW, HRR and RPR are associated with one-year mortality in ICU patients with hypertensive CKD. RDW exhibited modest predictive discrimination among the three markers and provides supplementary information for risk stratification when combined with established clinical risk scores. Prospective studies with external validation are warranted to confirm these findings and elucidate underlying mechanisms.