Red blood cell (RBC) distribution width (RDW) measures RBC variations in size. Higher RDW values have been associated with poor outcome in acute heart failure (HF). We aimed to assess the prognostic impact of the RDW in chronic HF.

We retrospectively analysed a cohort of chronic HF patients with left ventricular systolic dysfunction followed in our HF clinic between January 2012 and May 2018. Patients with missing data concerning RDW were excluded. Patients were categorized according to RDW tertiles: ≤13.5%; between 13.5 and 14.7%; and >14.7%. Patients were followed until January 2021; all-cause mortality was the end point analysed. The association of RDW with all-cause mortality was assessed with a Cox-regression analysis. Two multivariate models were built.

We studied 860 chronic HF patients, 66.4% males, mean age 70 (standard deviation, SD 13) years. Patients were followed for a median of 49 (29–82) months. During this period, 423 (49.2%) patients died. Mortality increased with increasing RDW tertiles. Patients with RDW >14.7% had a HR of mortality of 1.95 (1.47–2.58), p < 0.001 (model 1) and of 1.81 (1.35–2.41), p < 0.001 (model 2) when compared with those with RDW ≤13.5. Patients in the second RDW tertile had an all-cause death HR of 1.47 (1.12–1.93) and of 1.44 (1.09–1.90) in models 1 and 2, respectively.

Chronic HF patients with RDW values >14.7% presented an almost 2-fold higher risk of dying in the long term than those with RDW <13.5%. RDW is a widely available and easily measured parameter that can help clinicians in the risk stratification of chronic HF patients.