Ejection fraction and mortality: a nationwide register-based cohort study of 499 153 women and men

Aims: We investigated the sex-based risk of mortality across the spectrum of left ventricular ejection fraction (LVEF) in a large cohort of patients in Australia.

Methods and results: Quantified levels of LVEF from 237 046 women (48.1%) and 256 109 men undergoing first-time, routine echocardiography (2000-2019) were linked to 119 232 deaths (median 5.6 years of follow-up). Overall, 17.6% of men vs. 8.3% of women had an LVEF <50%. An LVEF <40% was associated with the highest crude cardiovascular-related and all-cause mortality at 5 years (∼20-30% and ∼ 40-50%, respectively). Thereafter, actual cardiovascular-related and all-cause mortality at 5 years in both sexes steeply improved to a nadir LVEF of 65.0-69.9% (reference group). Below this LVEF level, the adjusted hazard ratio (HR) for cardiovascular-related mortality for a LVEF of 55.0-59.9% was 1.36 [95% confidence interval (CI) 1.16-1.59; P < 0.001] in women and 1.21 (95% CI 1.05-1.39; P = 0.008) in men. In women, an LVEF of 60.0-64.9% was also associated with a HR 1.33 (95% CI 1.16-1.52; P < 0.001) for cardiovascular-related mortality. These associations were most striking in women and men aged <65 years and were replicated in those with suspected heart failure (32 403 cases aged 65.2 ± 16.1 years, 57.0% women). For pre-existing heart failure (33 738 cases aged 67.6 ± 16.9 years, 46.5% women), the specific threshold of increased mortality was at and below 50.0-54.9%.

Conclusions: Among patients investigated for suspected or established cardiovascular disease, we found clinically relevant sex-based differences in the distribution and mortality associated with an LVEF <65.0-69.9%. Specifically, they suggest a greater risk of mortality at higher LVEF levels among women.