Cardiac Mortality-Risk Assessment Improved by Evaluation of Hemoglobin Level in Combination with Kidney Function in the Patients with Systolic Heart Failure: A Cohort Study

Abstract

Background: Anemia and chronic kidney disease have been shown to be determinants of the prediction of poor prognosis in heart failure (HF) patients, but there is little information on their relationship with cardiac events. We examined prognostic interactions among kidney dysfunction, hemoglobin (Hb) level and other clinical variables in chronic HF patients. Methods and Results: Following evaluations of Hb level, cardiac function and kidney functions, 612 consecutive HF patients with left ventricular ejection fraction (LVEF) less than 45% underwent echocardiography in a stable condition before discharge and were then followed up for an average interval of 54.6 months with a primary end point of cardiac events. For 107 (17.4%) fatal cardiac events documented, besides NYHA functional class and use of diuretics, nitrates and statins, multivariable Cox analysis revealed that estimated glomerular filtration rate (eGFR) and Hb were significant independent prognostic values with odds ratios of 0.741 (P<0.0001; 95% CI:0.657 to 0.834) and 0.987 (P=0.0256; 95% CI:0.974 to 0.998), respectively. ROC analysis showed 47.5 ml/min/1.73 m2 of eGFR and 11.9 g/dL of Hb level to be thresholds for identifying patients at increased risk for cardiac events. Conclusions: Decreased hemoglobin level and kidney dysfunction are independently and synergistically associated with increased cardiac events in chronic HF patients with reduced LVEF.