Prognostic implications of relative hypochromia in ambulatory patients with chronic systolic heart failure

Iron insufficiency has been associated with heart failure, but the impact of a reduction of hemoglobin content in the erythrocytes as estimated by mean corpuscular hemoglobin concentration (MCHC) to myocardial structure, performance, and long-term clinical outcomes has not been well-established. The authors examined hematologic data and long-term outcomes of 197 ambulatory patients with chronic systolic and symptomatic heart failure who underwent comprehensive echocardiographic evaluation. The authors observed that relative hypochromia (defined as low MCHC) was associated with higher natriuretic peptide levels (NT-proBNP, r=-0.40, P<.0001) and lower estimated glomerular filtration rate (eGFR; r=0.45, P<.0001) and correlated modestly with indices of left and right ventricular diastolic dysfunction (all P<.05), but were not related to left ventricular ejection fraction (LVEF, r=0.17, P=.079). After 5years of follow-up, lower MCHC levels were associated with higher risk of death, transplant, or heart failure hospitalization after adjusting for age, LVEF, eGFR, and New York Heart Association class (hazard ratio, 1.34; 95% confidence interval, 1.04-1.72; P=.025), particularly in those with above-median hemoglobin (>13.8g/dL; hazard ratio, 2.02; 95% confidence interval, 1.44-2.81, P<.0001). Taken together, the observations imply that physicians should take notice of the presence of relative hypochromia particularly in the absence of anemia in the setting of chronic systolic heart failure.