The Association between Red Cell Distribution Width and Worse Outcomes in Patients Hospitalized due to Chest Pain

Background: Red blood cell distribution width (RDW) is a measure of the degree of heterogeneity of erythrocyte volume. Higher RDW levels are associated with increased mortality among patients with acute coronary syndrome (ACS), heart failure and other cardiovascular diseases. The association between RDW levels and clinical outcomes in patients admitted with chest pain is not known.
Methods: A retrospective analysis of patients hospitalized due to chest pain during 2010-2016. Excluded were patients with the diagnosis of ACS in the emergency department (ED). Patients were divided into tertiles according to baseline ED RDW levels (≤13.1%, 13.1< RDW ≤ 13.9, >13.9%). Study endpoints were the diagnosis of ACS in the index hospitalization and during 1 year, and all-cause mortality during a median follow-up of 3.3 ±1.9 years.
Results: Included were 13,517 patients (mean age 58±13, 61% male). Increased RDW levels were associated with higher rates of ACS in the index hospitalization (7.9%, 8.8% and 10.0% for the 1^st, 2^nd, and 3^rd tertiles, respectively, p<0.01), ACS during 1-year (8.8%, 10.2% and 11.9%, respectively, p<0.01), and with all-cause mortality during follow-up (2.4%, 4.6% and 15.5%, respectively, p<0.01). In multivariate analysis, RDW levels > 13.9% (vs. ≤13.1%) were associated with ACS in the index hospitalization (OR 1.25, 95% CI 1.04-1.51, P=0.02), ACS during 1-year (OR 1.20, 95% CI 1.01-1.44, P=0.04), and with all-cause mortality (HR 2.20, 95% CI 1.72 to 2.81, p<0.01).
Conclusion: In this retrospective study in patients hospitalized with chest pain, higher levels of RDW were associated with future ACS and long-term mortality.