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Published on: June 30, 2023
The incremental prognostic effect of red blood cell distribution width in 28-day mortality among critically ill
Zhihui Yao1, Jing Xiao2, Ying Li3
1Department of Cardiovascular Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Background:
The prognostic impact of red blood cell distribution width (RDW) on adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF) has been established. However, its non-linear relationship and incremental prognostic value in critically ill HFpEF patients remain insufficiently explored.
Methods:
A retrospective cohort study was conducted involving 3802 HFpEF patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV, v3.1) database. Multivariable Cox regression and restricted cubic spline (RCS) analyses were performed to evaluate the association between RDW and 28-day mortality, adjusting for potential confounders. A prediction model was constructed by the least absolute shrinkage and selection operator (Lasso)-Cox regression, and receiver operating characteristic (ROC) curve was utilized to assessed the incremental prognostic effect of RDW on 28-day mortality prediction.
Results:
Within the final cohort of 1962 HFpEF patients, the incidence of 28-day mortality showed a significant increase across RDW tertiles (T1 9.4% vs T2 13.1% vs T3 22.9%, P < 0.001). The Kaplan-Meier analysis demonstrated significantly higher all-cause mortality risk among patients with higher RDW levels (log-rank P < 0.001). Multivariable Cox regression analysis revealed that RDW levels were independently correlated with all-cause mortality after adjusting for multiple variables for both continuous (HR 1.13, 95% CI: 1.07-1.19; P < 0.001) and categorical comparisons (T3 vs T1: HR 1.66, 95% CI: 1.20-2.29; P = 0.002). RCS analysis indicated a significant linear relationship between RDW levels and the risk of mortality (P < 0.001 for overall association; P = 0.222 for non-linearity). When RDW was incorporated into the basic prediction model constructed by Lasso-Cox regression (AUC = 0.814), it slightly improved the predictive ability for 28-day mortality (AUC = 0.819), as evidenced by an IDI of 0.017 (95% CI: 0.006-0.036) and an NRI of 0.140 (95% CI: 0.041-0.203).
Conclusions:
This study established a significant linear association between RDW at admission and poor prognosis in critically ill patients with HFpEF. Higher RDW levels were associated with increased 28-day mortality risk, suggesting that it may be a relevant biomarker for mortality risk stratification in HFpEF patients.
