Epidemiology, clinical characteristics, and outcomes for heart failure with improved ejection fraction by...

HF incidence increases with age. Novel treatments have led to more patients recovering LVEF, now classified as HF with improved ejection fraction (HFimpEF). However, the age-related epidemiology and prognosis of HFimpEF remain unclear.

We identified adults ≥18 years with incident HFrEF (LVEF ≤40%) between 2013 and 2022 within Kaiser Permanente Northern California (KPNC), a healthcare delivery system serving 4.5 million members. HFimpEF was defined as baseline LVEF ≤40% with improvement to ≥40%. HFimpEF incidence was assessed by baseline age categories (<50, 50-64, 65-79, ≥80 years [yrs]). Rates of worsening HF (WHF) events (i.e. HF-related hospitalization, ED, or outpatient visits) were compared between HFimpEF and persistent HFrEF patients across age using Cox proportional hazards models adjusted for sex, race, and EF at the time of incident HFrEF, including evaluation of a potential interaction by age.

Among 28 292 adults with incident HFrEF, 35% experienced HFimpEF, with lower rates at older ages: 43% (<50 yrs), 42% (50-64 yrs), 39% (65-79 yrs), and 21% (≥80 yrs) (P < .001 for trend). WHF incidence rates (per 100 person-years) increased with age: 10.6 [95% CI, 9.5-11.7] (<50 yrs), 14.5 [13.7-15.3] (50-64 yrs), 20.8 [20.0-21.6] (65-79 yrs), and 31.7 [29.9-33.5] (≥80 yrs). Patients with HFimpEF, compared to those with persistent HFrEF, had lower adjusted rates of WHF, a finding more prominent at lower ages (pinteraction by age <0.001).

HFimpEF is common within a year of incident HFrEF, more prevalent in younger patients, and is associated with continued residual risk. Compared to persistent HFrEF, improvements in LVEF are associated with lower risk of WHF or death across the age spectrum. Additional research is needed to understand HF symptom burden and medical therapy use in this population to inform shared decision-making.