Dear Sir

We read the article entitled ‘Red blood cell distribution width is associated with incidence of atrial fibrillation’ by Eryd et al. [1] in the recent issue of the Journal. The authors aimed to investigate the association between red blood cell distribution width (RDW) and incidence of first hospitalization due to atrial fibrillation (AF) in a population-based cohort. They concluded that RDW was associated with incidence of AF independently of several cardiovascular, nutritional and haematological factors in this study of middle-aged subjects from the general population. Their study provides important information on this clinically relevant condition. The ready availability of RDW at no additional cost may encourage its wider use in clinical practice in the future. We thank the authors for their valuable contribution.

Inflammation has a critically important role in pathophysiology as well as in the clinical outcomes of many diseases. New inflammatory markers are considered a major risk factor for cardiovascular morbidity and mortality [2]. RDW is a measure of the variability in the size of circulating red blood cells and is a part of the complete blood count. Recently, the findings of a number of studies have demonstrated that elevated RDW values are associated with poor prognosis in the setting of stable angina, acute coronary syndrome, coronary bypass surgery, heart failure, stroke, peripheral arterial disease and older age [3]. However, RDW may also reflect ethnicity, neurohumoral activation, renal dysfunction, thyroid disease, hepatic dysfunction, nutritional deficiencies (i.e. iron, vitamin B12 and folic acid), bone marrow dysfunction, inflammatory diseases, chronic or acute systemic inflammation [4] and use of some medications [5].

Finally, in addition to RDW, mean platelet volume [6], platelet distribution width, neutrophil-to-lymphocyte ratio, C-reactive protein and uric acid are also easy methods to determine the incidence of AF [7, 8]. These markers might be useful in clinical practice [9]. Furthermore, it would be helpful if the authors could specify how much time they spent measuring RDW, because delays from blood sampling can cause abnormal 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 AF. However, one should keep in mind that RDW alone, without other inflammatory indicators, may not provide precise information to clinicians about the inflammatory status and prognosis of AF patients.

Conflict of interest statement

The authors have no conflict of interest to declare.


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  • 1
    Eryd SA, Borné Y, Melander O et al. Red blood cell distribution width is associated with incidence of atrial fibrillation. J Intern Med 2013; 275: 8492.
  • 2
    Balta I, Balta S, Koryurek OM et al. Serum endocan levels as a marker of disease activity in patients with Behçet's disease. J Am Acad Dermatol 2013a (in press).
  • 3
    Balta S, Aydogan M, Kurt O, Karaman M, Demirkol S, Akgul EO. Red cell distribution width as a novel, simple, inexpensive predictor of mortality in patients with chronic heart failure. Int J Cardiol 2013b; 168: 304950.
  • 4
    Balta S, Demirkol S, Arslan Z, Unlu M, Celik T. Inflammatory status as a major role of risk factor for atrial fibrillation. J Thromb Thrombolysis 2013c (in press).
  • 5
    Fici F, Celik T, Balta S et al. Comparative effects of nebivolol and metoprolol on red cell distribution width and neutrophil/lymphocyte ratio in patients with newly diagnosed essential hypertension. J Cardiovasc Pharmacol 2013; 62: 38893.
  • 6
    Balta I, Balta S, Koryurek OM et al. Mean platelet volume is associated with aortic arterial stiffness in patients with Behçet's disease without significant cardiovascular involvement. J Eur Acad Dermatol Venereol 2013d (in press).
  • 7
    Balta S, Demirkol S, Kucuk U, Unlu M. Hemostatic markers can be pivotal roles of risk factors for new-onset atrial fibrillation. Platelets 2013e (in press).
  • 8
    Demirkol S, Balta S, Celik T et al. Carotid intima media thickness and its association with total bilirubin levels in patients with coronary artery ectasia. Angiology 2013a (in press).
  • 9
    Demirkol S, Balta S, Celik T et al. Assessment of the relationship between red cell distribution width and cardiac syndrome X. Kardiol Pol 2013b; 71: 4804.
  • 10
    Demirkol S, Balta S, Cakar M, Unlu M, Arslan Z, Kucuk U. Red cell distribution width: a novel inflammatory marker in clinical practice. Cardiol J 2013c; 20: 209.