Red Blood Cell Distribution Width and Mortality Risk in a Community-Based Prospective Cohort

Abstract

Red blood cell distribution width (RDW) is an automated measure of the heterogeneity of red blood cell sizes (eg, anisocytosis) and is routinely performed as part of a complete blood cell count.^1-3 The RDW is used in the differential diagnosis of anemia, but otherwise has received little attention. In a recent exploratory analysis of a large contemporary clinical heart failure trial (the CHARM [Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity] Program),⁴ higher RDW was found to be a strong and independent predictor of increased risk of mortality and adverse cardiovascular (CV) outcomes. The investigators confirmed these findings in a clinical database of patients who had undergone cardiac catheterization at Duke University Medical Center. A subsequent analysis of the Cholesterol and Recurrent Events trial,⁵ which included patients who had a previous myocardial infarction but no evidence of heart failure, reported that higher RDW strongly and independently predicted all-cause mortality and adverse CV outcomes. Thus, higher RDW was associated with an adverse prognosis in 3 separate cohorts of patients with established CV disease (CVD). Whether this association is present in the general population and whether the association of RDW with mortality risk is specific to CVD have not been examined.