Mid-range Ejection Fraction Does Not Permit Risk Stratification Among Patients Hospitalized for Heart Failure

European Society of Cardiology heart failure guidelines include a new patient category with mid-range (40%-49%) left ventricular ejection fraction (HFmrEF). HFmrEF patient characteristics and prognosis are poorly defined. The aim of this study was to analyze the HFmrEF category in a cohort of hospitalized heart failure patients (REDINSCOR II Registry). A prospective observational study was conducted with 1420 patients classified according to ejection fraction as follows: HFrEF, < 40%; HFmrEF, 40%-49%; and HFpEF, ≥ 50%. Baseline patient characteristics were examined, and outcome measures were mortality and readmission for heart failure at 1-, 6-, and 12-month follow-up. Propensity score matching was used to compare the HFmrEF group with the other ejection fraction groups. Among the study participants, 583 (41%) had HFrEF, 227 (16%) HFmrEF, and 610 (43%) HFpEF. HFmrEF patients had a clinical profile similar to that of HFpEF patients in terms of age, blood pressure, and atrial fibrillation prevalence, but shared with HFrEF patients a higher proportion of male participants and ischemic etiology, and use of class I drugs targeting HFrEF. All other features were intermediate, and comorbidities were similar among the 3 groups. There were no significant differences in all-cause mortality, cause of death, or heart failure readmission. The similar outcomes were confirmed in the propensity score matched cohorts. The HFmrEF patient group has characteristics between the HFrEF and HFpEF groups, with more similarities to the HFpEF group. No between-group differences were observed in total mortality, cause of death, or heart failure readmission.