Objective: This study aims to investigate the prognostic value of sex in patients with heart failure with mildly reduced ejection fraction (HFmrEF). 

Background: Limited data regarding the prognostic impact of sex in patients with HFmrEF is available. 

Methods: A large retrospective registry was used including all consecutive hospitalized patients with HFmrEF (i.e., left ventricular ejection fraction (LVEF) 41 – 49%) from 2016 to 2022 according to current European guidelines. The prognostic impact of sex was investigated (i.e. males vs. females) was investigated. The primary endpoint was the first heart-failure related re-hospitalization at 3 years. Secondary endpoints comprised amongst others in-hospital mortality. Kaplan-Meier, uni- and multivariable Cox regression analyses were applied for statistics.

Results: 803 consecutive HFmrEF patients were included (64% males and 36% females). Aminoterminal pro-brain natriuretic peptide (NT-pro BNP) levels were not significantly different according to sex (6730 pg/ml vs. 8669 pg/ml; p=0.267). At 3 years, the risk of heart failure related re-hospitalization was not different (8% vs. 11%; log rank p=0.181; HR=0.727; 95% CI 0.455 – 1.162; p=0.183), not even after multivariable adjustment (HR=0.822; 95% CI 0.506 – 1,334; p=0.427). Accordingly, in-hospital mortality rates were not different in both groups (4% vs. 3%; p=0.942). In contrast, a higher need for coronary revascularisation at 3 years was observed in males compared to females (6% vs. 3%; p=0.027; HR=2.333; 95% CI 2.333 – 5.062; p=0.032). 

Conclusions: In patients hospitalized with HFmrEF, no sex-related differences of re-hospitalization and mortality were observed, whereas males revealed higher rates of coronary revascularization at 3 years.