The Changing Role of Chest Pain in the Emergency Department Observation Unit

BACKGROUND: This study objective was to describe changes in the utilization of a protocol-driven emergency department observation unit (EDOU) for chest pain over time. METHODS: This is a retrospective serial cross-sectional study of data from a clinical data warehouse of a single integrated healthcare system. We estimated long-term trends (2009-2019) in EDOU visits at 4 system hospitals, using monthly proportions as the main outcome, and month of visit as the exposure variable, accounting for age and sex. Rate changes associated with compulsory use of the History, EKG, Age, Risk factors, Troponin (HEART) score in 2016 were analyzed. RESULTS: There were 83,168 EDOU admissions among 1.3 million ED visits during the study interval, with an average admission rate of 5.9% of ED visits. The most common conditions were chest pain (41.2%), transient ischemic attack (7.8%), dehydration (6.3%), syncope (5.8%), and abdominal pain (5.2%). In each hospital, there was a temporal annual decline in the proportion of EDOU visits for chest pain protocols ranging from -7.9% to -2.8%, an average rate of -3.3% per year (95% CI, -4.6% to -2.0%) or a 54% (from 54% to 25%) relative decline in over the 11-year study interval. This decline was significantly steeper in younger middle-aged patients (ages 39-49). The HEART score intervention had a small impact on baseline decline of -3.1% at the 2 intervention hospitals, reducing it by -1.5% (95% CI, -2.2% to -0.8%). CONCLUSIONS: Utilization of the EDOU for chest pain decreased over time, with corresponding increases in other conditions. This decline preceded the introduction of the HEART score.