Emergency Department Visits and Hospitalizations for the Uninsured in Illinois Before and After Affordable Care Act Insurance Expansion.

We describe changes in emergency department (ED) visits and the proportion of patients with hospitalizations through the ED classified as Ambulatory Care Sensitive Hospitalization (ACSH) for the uninsured before (2011-2013) and after (2014-2015) Affordable Care Act (ACA) health insurance expansion in Illinois. Hospital administrative data from 201 non-federal Illinois hospitals for patients age 18-64 were used to analyze ED visits and hospitalizations through the ED. ACSH was defined using Agency for Healthcare Research and Quality (AHRQ) Prevention Quality Indicators (PQIs). Logistic regression was used to test the effect of time period on the odds of an ACSH for uninsured Illinois residents, controlling for patient sociodemographic characteristics, weekend visits and state region. Total ED visits increased 5.6% in Illinois after ACA implementation, with virtually no change in hospital admissions. Uninsured ED visits declined from 22.9% of all visits pre-ACA to 12.5% in 2014-2015, reflecting a 43% decline in average monthly ED visits and 54% in ED hospitalizations. The proportion of uninsured ED hospitalizations classified as ACSH increased from 15.4 to 15.5%, a non-significant difference. Older uninsured female, minority and downstate Illinois patients remained significantly more likely to experience ACSH throughout the study period. ED visits for the uninsured declined dramatically after ACA implementation in Illinois but over 12% of ED visits are for the remaining uninsured. The proportion of visits resulting in ACSH remained stable. Providing universal insurance with care coordination focused on improved access to home and ambulatory care could be highly cost effective.