A U-shaped relationship between LVEF and the risk of heart failure hospitalization: a large hospital-based cohort study

Abstract Background Left ventricular ejection fraction (LVEF) is a frequently used metric for quantifying left ventricular function. Previous studies found a U-shaped relationship between LVEF and long-term survival. However, the association between the spectrum of LVEF and heart failure (HF) hospitalization remains unclear. Purpose We aim to investigate the distribution of HF hospitalizations across the spectrum of LVEF using a large hospital-based cohort. Methods Consecutive participants who underwent echocardiography (2002-2021) in a tertiary medical center in Taiwan were included. LVEF was measured by echocardiography using biplane Simpson’s method and was categorized into intervals of 5% from <20% to ≥70%. The study outcome was HF hospitalization by linking to the National Health Insurance Registry Database. Cox proportional hazards regression was used for analyses with adjustment for age, sex, hypertension, diabetes, hyperlipidemia, coronary artery disease, and history of HF. We used restricted cubic splines to demonstrate the distribution of HF hospitalizations across the spectrum of LVEF. Results 94,762 participants (age 59.7 ± 18.1, men 51.4%) were included. Adjusted hazard ratios (HR) for HF hospitalizations showed a U-shaped relationship between LVEF and the risk of incident HF hospitalization with a nadir of risk at LVEF of 60-70%. (Figure) Compared with the reference group (LVEF: 60-65%), subjects with LVEF> 70% had an HR of 1.49 (95% confidence interval [CI]: 1.21-1.84), and those with LVEF of 50-55% had an HR of 1.93 (95% CI: 1.68-2.22). Similar results with a nadir at 60-70% could be observed irrespective of different age groups defined by the World Health Organization (WHO), sex, with or without hypertension or diabetes. Conclusions A U-shaped relationship between LVEF and the risk of incident HF hospitalization can be observed, with a nadir at LVEF of 60-70%. LVEF ≥ 70% may be defined as supranormal LVEF that necessitates further HF treatment.Figure