Association of Medicaid Expansion Under the Affordable Care Act With Outcomes and Access to Rehabilitation in Young Adult Trauma Patients

IMPORTANCE Trauma is the leading cause of death and disability among young adults in the United States. Young adults are also the age group most likely to be uninsured. Implementation of Medicaid expansion through the Affordable Care Act (ACA) has increased insurance coverage, but its associations with trauma care and outcomes among young adults nationwide remain unknown. We examined whether Medicaid expansion, in its first year, was associated with changes in insurance coverage and improved outcomes in young adults hospitalized for traumatic injury. OBJECTIVE To assess the associations of ACA Medicaid expansion with insurance coverage, in-hospital mortality, failure to rescue, access to rehabilitation, and unplanned readmissions among hospitalized young adult trauma patients across many US states. DESIGN, SETTING, AND PARTICIPANTS We used the Healthcare Cost and Utilization Project State Inpatient Databases to examine changes in insurance coverage and risk adjusted outcomes among young adults (age 19 to 44 years) who were hospitalized for injuries before and after Medicaid expansion and open enrollment occurred (2012-2013 vs 2014) in 11 US states that expanded Medicaid through the ACA. We also performed difference-in-difference analyses to compare these changes between 3 expansion states and 3 non-expansion states within the same geographic region. RESULTS Of the 141 187 trauma patients hospitalized across 11 Medicaid expansion states, 43 871 (31.1%) were women, and the mean (SD) age was 31.4 (7.6) years. Medicaid expansion was associated with an increase in Medicaid coverage from 16 229 individuals (16.7%) to 15 358 individuals (34.9%) (difference: 18.2%[95% CI, 16.5%-20.0%]; P<.001), a decrease in lack of insurance from 27 016 individuals (27.8%) to 5589 individuals (12.7%) (difference: -15.1% [95% CI, -16.8% to -13.5%]; P<.001), and an increase in discharge to rehabilitation from 9220 individuals (11.4%) to 4736 individuals (12.6%) (difference: 1.16%[95% CI, 0.55%-1.77%]; P<.001). We found no significant reductions in in-hospital mortality, failure to rescue, or unplanned readmissions. Similar results were found when 3 of these states were compared with 3 geographically and demographically similar states that had not enacted Medicaid expansion. CONCLUSIONS AND RELEVANCE The first year of implementation of Medicaid expansion and open enrollment across 11 selected US states was associated with significant increases in Medicaid coverage, reductions in uninsured rates, and increased access to postdischarge rehabilitation among young adults hospitalized for injury. However, this study found no significant reductions in in-hospital mortality, failure to rescue, or unplanned readmissions.