Red blood cell distribution width predicts mortality of adult patients receiving veno-arterial extracorporeal membrane oxygenation.

ABSTRACT

BACKGROUND: Red blood cell distribution width (RDW) is a numerical measure of the variation in the size of circulating red blood cells. Recently, there is increasing interest in the role of RDW as a biomarker for inflammatory states and as a prognostication tool for a wide range of clinical manifestations. The predictive power of RDW on mortality among patients receiving mechanical circulatory support remains largely unknown. METHODS: A retrospective analysis of 281 VA-ECMO patients at a tertiary referral academic hospital from 2009 to 2019 was performed. RDW was dichotomized with RDW-Low <14.5% and RDW-High ≥14.5%. The primary outcome was all-cause mortality at 30 days and 1 year. Cox proportional hazards models were used to examine the association between RDW and the clinical outcomes after adjusting for additional confounders. RESULTS: 281 patients were included in the analysis. There were 121 patients (43%) in the RDW-Low group and 160 patients (57%) in the RDW-High group. Survival to ECMO decannulation [RDW-H 58% versus RDW-L 67%, p = 0.07] were similar between the two groups. Patients in RDW-H group had higher 30-days mortality (RDW-H 67.5% vs RDW-L 39.7%, p < 0.001) and 1 year mortality (RDW-H 79.4% vs RDW-L 52.9%, p < 0.001) compared to patients in the RDW-L group. After adjusting for confounders, Cox proportional hazards model demonstrated that patients with high RDW had increased odds of mortality at 30 days (hazard ratio 1.9, 95% CI 1.2-3.0, p < 0.01) and 1 year (hazard ratio 1.9, 95% CI 1.3-2.8, p < 0.01) compared to patients with low RDW. CONCLUSIONS: Among patients receiving mechanical circulatory support with VA-ECMO, a higher RDW was independently associated with increased 30-days and 1-year mortality. RDW may serve as a simple biomarker that can be quickly obtained to help provide risk stratification and predict survival for patients receiving VA-ECMO.