Response to Red Blood Cell Distribution Width Is a Predictor of Readmission in Cardiac Patients

Abstract

Ephrem G. Clin Cardiol. 2013. doi: 10.1002/clc.22116

To the Editor:

We read with interest article the titled “Red Blood Cell Distribution Width Is a Predictor of Readmission in Cardiac Patients” by Ephrem,1 which reported that an elevated red blood cell distribution width (RDW) is an independent predictor of hospital readmission in patients with unstable angina (UA) or non–ST‐elevation myocardial infarction (NSTEMI). The ready availability of RDW measurements at no additional cost may encourage its wider use in clinical practice.

Acute coronary syndromes (ACS) are the most common medical emergencies of coronary artery disease (CAD) patients. Because a very high mortality rate is observed in these patients, the diagnosis and treatment is important.2 There has been significant improvement in the management and diagnosis of these patients over the past decade. Nevertheless, more studies are needed to further optimize the management and diagnosis of ACS patients.3 Some inflammatory markers, such as C‐reactive protein (CRP), may predict short‐ and long‐term morbidity and mortality in patients with ACS.4 Also, a higher RDW is associated with an increased risk of all‐cause long‐term mortality.5 Recently, a number of studies have reported that elevated RDW levels are associated with poor prognosis in the setting of stable angina, ACS, coronary bypass surgery, heart failure, stroke, peripheral arterial disease and older age.6 However, RDW may also reflect ethnicity, neurohumoral activation, renal dysfunction, thyroid disease, hepatic dysfunction, nutritional deficiencies (ie, iron, vitamin B₁₂, and folic acid), bone marrow dysfunction, inflammatory diseases, chronic systemic inflammation, and use of some medications, or could represent an integrative measure of all these pathological processes occurring during the progression of CAD.7

Additionally, not only RDW, but also mean platelet volume, neutrophil lymphocyte ratio, CRP, and uric acid are easy methods to evaluate the cardiovascular disease of the patients.8 These markers might be useful in clinical practice.9 Finally, because Ephrem evaluated patients with UA or NSTEMI retrospectively in the study,1 the author might not accurately define how much time elapsed before measuring RDW levels; delaying blood sampling can cause abnormal results in RDW measurements.10

In conclusion, we believe that the findings of the current study will lead to further studies examining the relationship between RDW and ACS. However, RDW alone, without other inflammatory indicators, may not provide enough information about the inflammatory status and prognosis. We suggest that RDW should be evaluated together with other serum inflammatory markers.

Sevket Balta, MD
Sait Demirkol, MD
Department of Cardiology
Omer Kurt, MD
Hakan Sarlak, MD
Turgay Celik, MD
Department of Internal Medicine
Gulhane Medical Academy. Ankara, Turkey
Dimitri P. Mikhailidis, MD
Department of Clinical Chemistry
University College London Medical School
London, United Kingdom