Association between anemia, clinical features and outcome in patients hospitalized for acute heart failure syndromes

BACKGROUND: It remains unclear in which patients hospitalized for acute heart failure syndromes (AHFS) the presence of anemia increases the risk of morbidity or mortality because of the heterogeneity of this patient population. The aim of this study was to evaluate the influence of anemia on the clinical outcome in subgroups of patients hospitalized for AHFS. METHODS AND RESULTS: The study included patients from the Acute Decompensated Heart Failure Syndromes (ATTEND) registry, a nationwide hospital-based prospective observational multicenter cohort of 4842 patients with AHFS admitted to 53 hospitals in Japan. The primary endpoint was all-cause death after admission and the secondary endpoint was a composite of all-cause death and readmission for heart failure (HF). Anemia was detected in 58% of the patients. The all-cause death rate after admission was significantly higher in patients with anemia (31.3%) than in those without anemia (15.5%). To identify the predictors that influence the effect of anemia on all-cause mortality, subgroup analyses were performed. As a result, the presence of anemia on admission was associated with a significantly increased risk of all-cause death in patients aged <75 years, male patients, patients with new-onset heart failure (HF) and patients with a reduced ejection fraction (EF). CONCLUSIONS: The present subgroup analysis demonstrated that age, gender, prior hospitalization for HF and the EF (preserved or reduced) should be considered in patients with AHFS when assessing the clinical significance of anemia at admission in relation to the risk of all-cause mortality.