Red Cell Distribution width in Older Patients with Community-acquired Pneumonia in the Emergency Department

ABSTRACT

PURPOSE: Red cell distribution width (RDW) is a quantitative measure of variability in the size of circulating erythrocytes. Recent studies have shown that higher RDW is associated with increased mortality risk in patients with several diseases. In particular, community-acquired pneumonia (CAP) is a prevalent and potentially life-threatening infection and has poor prognosis in older patients. We investigated the association of RDW in older patients with CAP. METHODS: We conducted a retrospective analysis study during the period from May, 2013 to October, 2013. Patients older than 65 who were treated with CAP in our emergency department were included in this study. We divided the two groups by RDW 14.5%, the best cutoff value for mortality by receiver operating curve (ROC) analysis. The primary outcome was in-hospital mortality. APACHE II, SOFA, PSI Class, and CURB 65 were calculated. Multivariate logistic regression analysis was performed to determine the risk factors for mortality. RESULTS: A total of 569 patients were analyzed and overall mortality was 10.2%. Mean age was 76.7 years and range of RDW was 10.5%~26.2%. There were 208 patients above 14.5%. Significant differences in in-hospital mortality were observed between the two groups (15.0% vs. 22.1%, respectively). In multivariate logistic regression analysis, RDW>14.5% showed an association with mortality (OR=2.08, 95% CI 1.03-4.19). In ROC analysis, area under the curve of RDW was 0.716 (95%CI, 0.677-0.753). CONCLUSION: RDW at admission is associated with in-hospital mortality in older patients with CAP; and it might be a prognostic marker for mortality of CAP in older patients in the emergency department.