Endogenous Erythropoietin and Outcome in Heart Failure

Abstract

Endogenous erythropoietin is increased in patients with heart failure (HF). Previous small-scale data suggest that these erythropoietin levels are related to prognosis. This study aims to analyze the clinical and prognostic value of erythropoietin levels in relation to hemoglobin in a large cohort of HF patients. In patients hospitalized for HF, endogenous erythropoietin levels were measured at discharge and after 6 months. In anemic patients, the relation between erythropoietin and hemoglobin levels was determined by calculating the observed/predicted ratio of erythropoietin levels. We studied data from 605 patients with HF. Mean age was 71+/-11 years; 62% were male; and mean left ventricular ejection fraction was 0.33+/-0.14. Median erythropoietin levels were 9.6 U/L at baseline and 10.5 U/L at 6 months. Higher erythropoietin levels at baseline were independently related to an increased mortality at 18 months (hazard ratio, 2.06; 95% confidence interval, 1.40 to 3.04; P<0.01). In addition, persistently elevated erythropoietin levels (higher than median at baseline and at 6 months) were related to an increased mortality risk (hazard ratio, 2.24; 95% confidence interval, 1.02 to 4.90; P=0.044). The observed/predicted ratio was determined in a subset of anemic patients, 79% of whom had erythropoietin levels lower than expected and 9% had levels higher than expected on the basis of their hemoglobin. Multivariate Cox regression analysis revealed that a higher observed/predicted ratio was related to an increased mortality risk (hazard ratio, 3.52; 95% confidence interval, 1.53 to 8.12; P=0.003). Erythropoietin levels predict mortality in HF patients, and persistently elevated levels have an independent prognostic value. In anemic HF patients, the majority had a low observed/predicted ratio. However, a higher observed/predicted ratio may be related to an independent increased mortality risk.