Prognostic significance of red cell distribution width and other red cell parameters in patients with chronic heart failure during two years of follow-up

Abstract

Background: Studies published during the last decade seem to indicate red blood cell parameters as inexpensive, rapidly available, and simple tools for the assessment of prognosis in patients with chronic heart failure (CHF).

Aim: To evaluate the prognostic value of red cell parameters determined in a routine blood count in patients with CHF.

Methods: The study group included 165 patients with the New York Heart Association (NYHA) class II-IV CHF hospitalised in the 2nd Department of Cardiology in Bydgoszcz. On the first day of hospitalisation, all patients in the study group underwent a complete blood count with an assessment of haemoglobin (Hb) level, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and red blood cell distribution width (RDW). Follow-up was carried over 24 months by phone calls every 3 months.

Results: MCV, MCH and MCHC were not shown to be significant predictors of mortality in CHF patients at 1 and 2 years of follow-up. In univariate analysis at 1-year follow-up, the following variables were significantly associated with the occurrence of the study endpoint: Hb level (p = 0.022; HR = 0.80), RDW (p = 0.004; HR = 1.257), and N-terminal pro-B-type na-triuretic peptide (NT-proBNP) level (p = 0.0001; HR = 1). At 2 years of follow-up, the following variables were significantly associated with the occurrence of the study endpoint: left ventricular ejection fraction (p = 0.018; HR = 0.956), NYHA class (p = 0.007; HR = 0.378), RDW (p = 0.044; HR = 1.175), and NT-proBNP level (p < 0.001; HR = 1). Multivariate analysis for 1-year follow-up showed that RDW and NT-proBNP level were independent significant predictors of mortality, while NT-proBNP level (p = 0.006; HR = 1) and NYHA class (p = 0.024; HR = 0.439) were significant predictors of mortality at 2 years of follow-up. Based on receiver operating characteristic curve analysis, the cut-off RDW was 15.00% (AUC = 0.63; 0.523-0.737), at 12 months of follow-up and 14.00% (AUC = 0.6; 0.504-0.697), at 24 months of follow-up. The cut-off for Hb level was 13.9 g/dL (AUC = 0.662; 0.553-0.77), at 12 months of follow-up and 12.2 g/dL (AUC = 0.581; 0.482-0.681), at 24 months of follow-up.

Conclusions: Baseline RDW and Hb level in patients hospitalised with the diagnosis of NYHA class II-IV CHF seem to be important predictors of mortality in this population. Among the red blood cell parameters, only RDW was shown to be an independent prognostic factor at 1 year of follow-up but it appeared to lose its significance during longer-term follow-up.

Keywords: chronic heart failure; haemoglobin; red blood cell distribution width; red blood cell parameters.