The Affordable Care Act and emergency department use by low acuity patients in a US hospital

Background The Affordable Care Act (ACA) is one of the biggest healthcare reforms in US history. A key issue is the ACAs effect on low acuity, potentially primary care patients. This study evaluates the effect of the ACA on low acuity patients seen in the emergency department (ED). Methods This is an age-period-cohort analysis for a community hospital ED in Michigan, from 2009 to 2015. Patients were stratified by age, year seen, emergency severity index (ESI) and insurance status. Data were compared between before and after ACA along with descriptive statistics, Chi-square and Student t-tests. The primary outcome was the change in ED usage by low acuity. Patients > 65 were used as a temporal control. Results 305,350 ED visits were analyzed. ED visits with ESI 4/5 increased from 11.9% to 14.8%. Patients 65 increased from 5.1% to 6.5%. Patients