A study on the predictive value of red blood cell distribution width as a biomarker of outcome in paediatric critical illness

Abstract

Background: Red blood cell distribution width (RDW) is a simple, low cost measure, which is routinely reported as a standard component of complete hemogram. Several recent studies have found a positive association between RDW and risk of both morbidity and mortality in several diseases, particularly in critically ill adults.But, data regarding the outcome predictive utility of RDW in critically ill paediatric population is limited. The objective of the study was to determine the association between RDW and mortality and morbidity in paediatric critical illness.Methods: A cross sectional observational study was conducted from February 2019-May 2019 at Cheluvamba Hospital, Mysuru. 97 subjects admitted to Paediatric intensive care unit (PICU) were included in the study. Data regarding subject demographics, hospitalization characteristics, laboratory values and outcomes were collected.Results: A significant positive correlation was found between mortality among critically ill children and RDW measured within 24 hours of PICU admission (p=0.01) and peak RDW during the first 7 days of PICU stay (p=0.01). The relative change in RDW correlated significantly (p=0.01) with the number of intensive care unit (ICU) free days. Our subjects were divided into quartiles based on the admission RDW, subjects in the fourth quartile were found to have the highest mean Paediatric risk of mortality (PRISM III) score, Paediatric index of mortality (PIM 2) score and the least number of ICU free days. Area under the receiver operator curve (AUROC) for incidence of death was 0.706 for admission RDW,0.71 for peak RDW and 0.882 for PIM 2 score.Conclusions: Our data demonstrates that RDW at the time of PICU admission could serve as a cost-effective marker for early identification of critically ill paediatric population who are at risk for adverse outcomes.