Analysis of Worsening Heart Failure Events in an Integrated Health Care System

There is growing interest to disentangle worsening heart failure (WHF) from location of care and move away from hospitalization as a surrogate for acuity. The purpose of this study was to describe the incidence of WHF events across the care continuum from ambulatory encounters to hospitalizations. We studied calendar year cohorts of adults with diagnosed heart failure (HF) from 2010-2019 within a large, integrated health care delivery system. Electronic health record (EHR) data were accessed for outpatient encounters, emergency department (ED) visits/observation stays, and hospitalizations. WHF was defined as ≥1 symptom, ≥2 objective findings including ≥1 sign, and ≥1 change in HF-related therapy. Symptoms and signs were ascertained using natural language processing. We identified 103,138 eligible individuals with mean age 73.6 ± 13.7 years, 47.5% women, and mean left ventricular ejection fraction of 51.4% ± 13.7%. There were 1,136,750 unique encounters including 743,039 (65.4%) outpatient encounters, 224,670 (19.8%) ED visits/observation stays, and 169,041 (14.9%) hospitalizations. A total of 126,008 WHF episodes were identified, including 34,758 (27.6%) outpatient encounters, 28,301 (22.5%) ED visits/observation stays, and 62,949 (50.0%) hospitalizations. The annual incidence (events per 100 person-years) of WHF increased from 25 to 33 during the study period primarily caused by outpatient encounters (7 to 10) and ED visits/observation stays (4 to 7). The 30-day rate of hospitalizations for WHF ranged from 8.2% for outpatient encounters to 12.4% for hospitalizations. ED visits/observation stays and outpatient encounters account for approximately one-half of WHF events, are driving the underlying growth in HF morbidity, and portend a poor short-term prognosis.

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