Impact of red blood cell distribution width on long-term mortality in patients with ST-elevation myocardial infarction.

Objectives: Recent studies have reported increased red blood cell distribution width (RDW) has been associated with adverse outcomes in heart failure and stable coronary disease. We investigated the association between RDW and risk of all-cause mortality in patients with ST-elevation myocardial infarction (STEMI) who were free of heart failure at baseline.

Methods: We enrolled 691 patients with STEMI who were free of heart failure at baseline confirmed by coronary angiography in Beijing Friendship Hospital from January 2007 to December 2008. According to the median RDW at baseline (13.0%) on admission, the patients were divided into two groups: a low-RDW group (RDW <13.0%, n = 329) and a high-RDW group (RDW ≥13.0%, n = 362). All-cause mortality rates were compared between groups. Mean duration of follow-up was 41.8 months. The relation between RDW and clinical outcomes after hospital discharge were tested using Cox regression models, adjusting for clinical variables. At the same time, the sensitivity and specificity of RDW were analyzed by ROC analysis.

Results: Forty-seven patients (6.8%) died during follow-up. The cumulative incidence of all-cause death was significantly higher in the high-RDW group than in the low-RDW group (log-rank p = 0.007). Multivariate analysis revealed that high RDW was associated with all-cause mortality (hazard ratio: 3.43; 95% confidence interval: 1.17-8.32; p = 0.025). The area under the ROC curve was 0.562.

Conclusion: From the statistical point of view, increased RDW is associated with all-cause and cardiac mortality rates in patients with STEMI who were free of heart failure at baseline. But RDW is a marker with a very low prognostic accuracy that does not seem to be clinically helpful.