Relation between red blood cell distribution width (RDW) and all-cause mortality at two years in an unselected population referred for coronary angiography

https://doi.org/10.1016/j.ijcard.2008.11.187Get rights and content

Abstract

Background

Red blood cell distribution width (RDW), a numerical measure of the variability in size of circulating erythrocytes, has recently been shown to be a strong predictor of adverse outcomes in patients with heart failure and in patients with prior myocardial infarction but no symptomatic heart failure at baseline, even after adjustment for hematocrit. However, there are no data in other cardiac populations, including patients with acute coronary syndromes (ACS).

Methods

The present study investigated the long-term prognostic significance of baseline RDW in a well-characterized cohort of 389 male patients who were referred to coronary angiography for a variety of indications. All patients were followed prospectively for all-cause mortality, and data regarding this endpoint was available for 97% of the population at 24 months.

Results

After controlling for a variety of baseline variables (including hemoglobin and the presence of heart failure), RDW (analyzed as a categorical variable comparing the upper tertile of baseline values to the lower two levels combined) was a strong and independent predictor of all-cause mortality using a Cox proportional hazards model [hazard ratio (HR) 2.69, 95% confidence interval (CI) 1.50–4.84, p = 0.0008]. In addition, baseline RDW was also an independent predictor of all-cause mortality in the non-anemic (HR 4.73, 95% CI 2.06–10.86, p = 0.0003) and ACS (HR 2.90, 95% CI 1.32–6.38, p = 0.0082) subpopulations of patients.

Conclusions

These data demonstrate that elevated RDW is a strong and independent predictor of all-cause mortality in an unselected population of male patients across a broad spectrum of risk (including ACS) referred for coronary angiography.

Introduction

Anemia has been shown to be a powerful and independent predictor of adverse cardiovascular outcomes in multiple patient populations [1], [2], [3], [4], [5], [6]. More recently RDW, a numerical measure of the variability in size of circulating erythrocytes, has also been shown to be a strong predictor of adverse outcomes in patients with heart failure [7] and in patients with prior myocardial infarction but no symptomatic heart failure at baseline [8], even after adjustment for hematocrit. Accordingly, we tested the hypothesis that higher values of RDW are associated with the risk of all-cause mortality in a broad and unselected population of male patients referred to coronary angiography for a variety of indications, including ACS.

Section snippets

Study design

This was an observational study derived from a cohort of patients prospectively entered into a database for the purpose of examining the prognostic significance of various plasma biomarkers in patients with known or suspected coronary artery disease. The study population and design have been previously described in detail elsewhere [9]. Briefly, 389 male patients undergoing coronary angiography for a variety of indications constituted the study population. Patients presenting with ST-segment

Baseline characteristics

A total of 389 patients constituted the study population. The baseline clinical, laboratory and angiographic characteristics of the study population stratified by the upper tertile of RDW values are shown in Table 1. Higher RDW values were seen in association with hypertension and CHF on presentation, while lower RDW values were seen in association with baseline use of beta blockers and statins. RDW was also negatively correlated with hemoglobin. In the entire study population, there was a

Discussion

The primary finding of this study was that increased RDW was a strong and independent predictor of mortality in an unselected population of males referred for coronary angiography. This association remained significant even after adjustment for a wide variety of clinically relevant covariates. These covariates included not only important laboratory and clinical parameters (such as hemoglobin and CHF on presentation), but also angiographic variables such as the extent of coronary artery disease

Acknowledgement

The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [12].

Cited by (0)

View full text