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Abstract

Introduction: Red cell distribution width (RDW) has been associated with adverse outcomes related to invasive infections in critically ill adults; it is routinely measured as part of the complete blood count, and has potential as an inexpensive and readily available prognostic biomarker in critically ill children. Hypothesis: We hypothesized that RDW is associated with severity of illness and mortality in patients admitted to the pediatric intensive care unit (PICU) with sepsis. Methods: We performed a prospective cohort study of 90 consecutive pediatric patients with severe sepsis or septic shock admitted to an academic PICU from May 2009 to June 2010; 88 patients had a RDW collected within 24 hours of sepsis diagnosis and were included for analysis. We determined the association of RDW with hemoglobin using Spearman’s Rho. Using published data, we categorized RDW? 14.5 as normal, 14.6-16.0 as mildly elevated, and >16.0 as severely elevated. We compared PIM-2 score, ventilator-free days, vasoactive-free days, and PICU LOS as markers of illness severity in RDW groups using the Kruskal-Wallis test. We compared mortality between RDW groups using the?2 test. The area under the ROC curve was used to evaluate the role for initial RDW to determine vital status at PICU discharge. Results: The median (IQR) age was 9 years (1 mo-14 yrs), 43% were male, and 42% were White. The median (IQR) RDW was 15.2 (12.6-17.2). RDW was not correlated with hemoglobin (r=-0.08, p=0.44), supporting that RDW changes were not solely due to anemia. Across normal, mildly elevated, and severely elevated RDW groups, there was no significant difference in PIM-2 (p=0.24), ventilator-free days (p=0.81), vasoactive-free days (p=0.72), or PICU LOS (p=0.98). Mortality was 6/29 (31.6%) in normal, 4/27 (21.1%) in mildly elevated, and 9/32 (47.4%) in severely elevated RDW groups (p=0.46). The AUC for RDW to predict PICU mortality was 0.59 (95% CI, 0.43, 0.76). Conclusions: Unlike in adults, RDW was not associated with severity of illness or mortality in critically ill children with sepsis. More research is needed to determine the significance of RDW in a broader PICU population.