Background: Red blood cell distribution width (RDW) is a component of the complete blood count (CBC) that is traditionally used to identify iron-deficiency anemia. RDW has been shown to predict mortality in patients with multiple different medical conditions and in general populations. It is unknown whether RDW predicts outcomes in trauma patients. This study tested whether RDW predicts mortality in a trauma population at a Level I trauma center.
Methods: Trauma patients with a CBC from October 2005 to December 2011 were evaluated. Sex-specific 30-day and 1-year all-cause mortality and RDW were studied using Cox regression adjusted for age, Injury Severity Score (ISS), hospital length of stay, blunt versus penetrating trauma, and other CBC parameters.
Results: A total of 3,637 females and 5,901 males were evaluated at 30 days and 1 year. With full adjustment, RDW predicted 30-day mortality in males (for RDW quintiles 1-5: 2.2%, 1.8%, 3.6%, 4.8%, 10.1%, respectively; p < 0.001) but not in females (3.4%, 1.9%, 3.0%, 3.9%, 6.2%; p = 0.036). At 1 year, RDW predicted mortality in both males (p < 0.001; 0.5%, 0.4%, 0.8%, 1.7%, and 8.3%) and females (p < 0.001; 0.5%, 2.1%, 3.0%, 4.2%, and 8.8%). Receiver operating characteristic analysis found c = 0.705 in males and c = 0.625 in females at 30 days and c = 0.820 in males and c = 0.723 in females at 1 year.
Conclusion: RDW independently predicted mortality in trauma patients at this single Level I trauma center. RDW may reveal underlying health status and be clinically useful for prognostication. The mechanistic relationship between RDW and mortality in trauma remains unknown and should be further evaluated.
Level of evidence: Prognostic and epidemiological study, level III.