The relationship between red blood cell distribution width and the clinical outcomes in non-ST elevation myocardial infarction and unstable angina pectoris: a 3-year follow-up

Abstract

Objectives Red blood cell distribution width (RDW), a marker of variation in the size of the circulating red blood cells, was evaluated in patients with non-ST elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP). Background Higher RDW is associated with mortality in the general population, particularly in those with symptomatic cardiovascular disease, and heart failure. We hypothesized that admission RDW might be predictive of adverse clinical outcomes for patients with NSTEMI and UAP. Methods We prospectively enrolled 310 patients with NSTEMI and UAP (mean age 59.3 +/- 11.9 years; 236 men, 74 women) in this study. Admission RDW was measured and the study population was classified on the basis of RDW tertiles. A high RDW (n = 95) was defined as a value in the upper third tertile (> 14%) and a low RDW (n = 215) was defined as any value in the lower two tertiles (<= 14%). The patients were followed up for clinical outcomes for up to 3 years after discharge. Results In the Kaplan-Meier survival analysis, the 3-year mortality rate was 19% in the high RDW group versus 5.6% in the low RDW group (P < 0.001). In the receiver operating characteristic curve analysis, an RDW value of more than 14% yielded a sensitivity of 60% and a specificity of 72.5%. A significant association was found between a high admission RDW level and the adjusted risk of cardiovascular mortality (hazard ratio: 3.2, 95% confidence interval: 1.3-7.78, P = 0.01). Conclusion RDW is a readily available clinical laboratory value associated with long-term cardiovascular mortality in NSTEMI and UAP.