Abstract 4138433: Prevalence, Clinical Characteristics, and Outcomes in Heart Failure with Improved Ejection Fraction by Chronological Age

Background: HF incidence increases with age. Modern treatments have led to more patients recovering LVEF, classified as HF with improved ejection fraction (HFimpEF). However, the age-related epidemiology and prognosis of HFimpEF remain unclear. Hypothesis: Compared to younger patients, older patients will have lower rates of HFimpEF after incident HFrEF and higher rates of HF-related morbidity and mortality. Aims: To describe the clinical characteristics and outcomes in HFimpEF across the age spectrum within a healthcare delivery system in the US. Methods: We identified adults ≥18 years with incident HFrEF (LVEF≤40%) between 2013-2018 within Kaiser Permanente Northern California (KPNC), a healthcare system serving 4.5 million members. HFimpEF was defined as baseline LVEF <40% with subsequent >10% 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 and EF at the time of incident HFrEF, including potential interaction by age modeled continuously (cubic splines with 3 knots). Data: Among 12,639 adults with incident HFrEF, 33% experienced HFimpEF, with lower rates at older ages: 42% (<50 yrs), 41% (50-64 yrs), 35% (65-79 yrs) and 18% (≥80 yrs). Among patients with HFimpEF alive at 1-year post-HFrEF (N=9954), WHF incidence (per 100 p-y) remained high (10.7) in younger (<50 yrs) patients and increased by age: 14.5 (50-64 yrs), 21.6 (65-79 yrs), and 33.7 (≥80 yrs)(P <0.001 for trend; Figure, Panel A). Patients with HFimpEF, compared to those with persistent HFrEF, had lower adjusted rates of WHF across the spectrum of age (pinteraction by age < 0.001; Figure, Panel B). Conclusion: HFimpEF is common within a year of incident HFrEF, more prevalent in younger patients, and is associated with significant residual clinical risk. Compared to persistent HFrEF, improvements in LVEF are associated with a lower risk of WHF or death. Additional research is needed to understand HF symptom burden and medical therapy use in this population.