66 Impact of High-Risk HEART Score on Readmission Rates, Observation Unit Utilization, and Length of Stay

Abstract

The HEART Score, which assesses patient history, electrocardiogram (ECG), age, risk factors, and troponin level, is a clinical decision tool used in the emergency department (ED) evaluation of chest pain to calculate the six-week risk for potential major adverse cardiac events (MACE). Low-risk (HEART score ≤ 3) and high-risk (HEART score >3) groups have been shown to carry a 1.7% and 12-17% rate of a MACE within 6-weeks, respectively. The objective of this study was to evaluate differences in 60-day readmission rate, patient placement, and length of stay between low- and high-risk patient groups, according to HEART Score. In this single-institution, retrospective cohort study, ED patients seen during a five-month period were dichotomized into low-risk (HEART score ≤ 3) and high-risk (HEART score >3) groups. Each HEART score component (history, ECG, age, risk factors, and troponin) was given a sub-score between 0-2 based on clinical or diagnostic severity. Two physicians independently reviewed individual patient history and ECG, with adjudication performed by a third physician reviewer. The primary endpoint was 60-day readmission rate. Secondary endpoints included patient placement (discharge, observation, inpatient) and length of stay (LOS). A total of 558 ED patients (n=321 low risk; n=237 high risk) were included. Baseline demographics were well matched between groups. High-risk patients had a greater 60-day readmission rate compared to low-risk patients (18.7% vs. 25.9%, respectively; p=0.046). The high-risk cohort was more likely to be admitted to hospital observation units (40.9% vs. 24.6%; p<0.01) and inpatient settings (23.31% vs. 5.61%; p<0.01). In contrast, low-risk patients had greater discharge rates compared to those considered high-risk (69.5% vs. 35%; p<0.01). The difference in median LOS between low- and high-risk groups admitted to inpatient settings was not statistically significant (43.0 hours vs. 41.4 hours; p=0.97). However, median ED LOS was greater for low-risk patients (4.3 hours vs. 3.88 hours; p=0.01), and median observation unit LOS was greater for high-risk patients (23.6 hours vs. 19.3 hours; p=0.02). In calculating composite HEART score, high-risk patients were more likely to score greatest (2/2) on age and risk factor components (50.2% and 64.9%, respectively), compared to the ECG, history and troponin factors (13.78%, 21,1%, and 1.30%, respectively). High-risk HEART score was associated with greater 60-day readmission rates, and observation unit and inpatient admissions. This finding may reflect the clinical realities of treating more complex patient populations. The age and risk factor components were the most significant contributors to high-risk HEART scores, and may be weighed more heavily by physicians during clinical assessments of emergent chest pain.