Obesity Paradox in Heart Failure with Mildly Reduced Ejection Fraction

The study investigates the prognostic impact of body mass index (BMI) in patients hospitalized with heart failure with mildly reduced ejection fraction (HFmrEF).

Limited data regarding the prognostic impact of BMI in patients with HFmrEF is available.

Consecutive patients with HFmrEF (ie, left ventricular ejection fraction 41-49% and signs and/or symptoms of HF) were retrospectively included at one institution from 2016 to 2022. Risk stratification was performed according to WHO-defined BMI groups. The primary endpoint was all-cause mortality at 30 months (median follow-up). Kaplan-Meier, uni- and multivariable Cox proportional regression analyses were applied for statistics.

1832 consecutive patients with HFmrEF were included with a median BMI of 26.7 kg/m² (IQR 24.0-30.8 kg/m²). Patients with lowest BMI (ie, 18.5-24.9 kg/m²) were associated with highest risk of all-cause mortality at 30 months compared to patients with higher BMI values (40.0% vs 29.0% vs 21.4% vs 20.9%; log rank p = 0.001; HR = 0.721; 95% CI 0.656-0.793; p = 0.001). Even after multivariable adjustment, higher BMI values were associated with improved survival at 30 months (HR = 0.963; 95% CI 0.943-0.985; p = 0.001). In contrast, the risk of HF- related rehospitalization at 30 months was not affected by BMI (log rank p = 0.064).

In patients hospitalized with HFmrEF, lower BMI was associated with increased risk of all-cause mortality at 30 months, suggesting an obesity paradox in HFmrEF.