Abstract 13550: Understanding Associations of Hospital Admission or Observation With Patient Outcomes After Emergency Department Evaluation for Suspected Acute Coronary Syndrome

Abstract

Introduction: Evaluation for suspected acute coronary syndrome (ACS) results in millions of emergency department (ED) visits annually, and accounts for billions in health care costs. Understanding the benefits of hospitalization among patients who ruled out for an acute myocardial infarction (AMI) will inform physician decision making and future health care policies. Hypothesis: Hospital admission does not improve 30-day patient outcomes (death/AMI) compared to those discharged after ED evaluation for suspected ACS. Methods: We compared the effectiveness of hospitalization vs outpatient follow-up for a cohort of patients with chest pain presenting to one of 13 EDs within the Kaiser Permanente Southern California region between January 1, 2015 and December 1, 2017. The primary outcome was AMI or all-cause mortality, and secondary outcomes included revascularization and a composite MACE outcome within 30-days of ED visit. Adjusting for patient age, gender, race, ACS risk factors and chronic co-morbidities an instrumental variable (IV) analysis was used to evaluate the effect of hospitalization on patient outcomes Results: Of 77,562 chest pain patient encounters not identified as an AMI during the ED encounter, 322 (0.4%) went on to have an AMI (n=193, 0.2%) or died (n=137, 0.2%) within 30-days of ED visit (1.5% admitted vs 0.2% discharged). This included 200 (0.3%) patients who underwent coronary revascularization (0.7% admitted vs 0.2% discharged). IV analysis found no adjusted differences in 30-day patient outcomes between the hospitalized cohort and those discharged (risk reduction 0.002, 95% CI -0.002 to 0.007). Similarly, there were no differences in coronary revascularization (risk reduction 0.003, 95% CI -0.002 to 0.007). Conclusions: Among ED patients with chest pain who are not identified with an AMI, there does not appear to be a benefit in 30-day outcomes for patients who are hospitalized compared to those discharged with outpatient follow-up.