Relationship of plasma erythropoietin to long-term outcome in acute coronary syndrome

BackgroundErythropoietin has been related to adverse prognosis in patients with heart failure, but it is unknown whether it adds prognostic information in acute coronary syndrome.MethodsPlasma erythropoietin was measured on admission with enzyme-linked immunosorbent assay in 627 patients. Patients were divided into three groups depending on their erythropoietin level and followed for myocardial infarction (MI) (median 6 months) and mortality (median 39 months). Cox regression models were used to evaluate erythropoietin compared to clinical variables; age, gender, diabetes, smoking, prior MI, heart failure, hypertension and revascularization. In a second Cox regression model, laboratory markers were assessed; hemoglobin, estimated glomerular filtration rate (eGFR), C-reactive protein (CRP), cardiac troponin T (cTnT) and N-terminal pro-brain-natriuretic peptide (NT-proBNP).ResultsPatients with the highest erythropoietin level (> 8.8 mU/mL, n = 205) had a 47% increased mortality (HR 1.47, 95% CI 1.04–2.06, p = 0.028) when adjusted for clinical variables. Compared to laboratory risk markers, erythropoietin added prognostic information (HR 1.59, 95% CI 1.05–2.38, p = 0.027) when adjusted for hemoglobin, eGFR and CRP. Erythropoietin (HR 1.21, 95% CI 0.79–1.86, p = 0.387) was no longer significantly associated with mortality when cTnT and NT-proBNP were added. Erythropoietin was not related to the risk of future MI (HR 1.24, 95% CI 0.65–2.33, p = 0.513).ConclusionElevated erythropoietin level was associated with increased mortality in patients admitted with possible ACS when adjusted for clinical variables, or for kidney function and hemoglobin. However, erythropoietin does not add prognostic information when markers of myocardial necrosis and dysfunction are available in ACS.