Insurance expansion and hospital emergency department access: Evidence from the affordable care act

Craig Garthwaite, Tal Gross, Matthew Notowidigdo, John A. Graves*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Background: Little is known about whether insurance expansion affects the location and type of emergency department (ED) use. Understanding these changes can inform state-level decisions about the Medicaid expansion under the Patient Protection and Affordable Care Act (ACA). Objective: To investigate the effect of the 2014 ACA Medicaid expansion on the location, insurance status, and type of ED visits. Design: Quasi-experimental observational study from 2012 to 2014. Setting: 126 investor-owned, hospital-based EDs. Participants: Uninsured and Medicaid-insured adults aged 18 to 64 years. Intervention: ACA expansion of Medicaid in January 2014. Measurements: Number of ED visits overall, type of visit (for example, nondiscretionary or nonemergency), and average travel time to the ED. Interrupted time-series analyses comparing changes from the end of 2013 to end of 2014 for patients from Medicaid expansion versus nonexpansion states were done. Results: There were 1.06 million ED visits among patients from 17 Medicaid expansion states, and 7.87 million ED visits among patients from 19 nonexpansion states. The EDs treating patients from Medicaid expansion states saw an overall 47.1% decrease in uninsured visits (95% CI, - 65.0% to - 29.3%) and a 125.7% (CI, 89.2% to 162.6%) increase in Medicaid visits after 12 months of ACA expansion. Average travel time for nondiscretionary conditions requiring immediate medical care decreased by 0.9 minutes (- 6.2% [CI, - 8.9% to - 3.5%]) among all Medicaid patients from expansion states. We found little evidence of similar changes among patients from nonexpansion states. Limitation: Results reflect shifts in ED care at investor-owned facilities, which limits generalizability to other hospital types. Conclusion: Meaningful changes in insurance status and location and type of ED visits in the first year of ACA Medicaid expansion were found, suggesting that expansion provides patients with a greater choice of hospital facilities. Primary Funding Source: Robert Wood Johnson Foundation.

Original languageEnglish (US)
Pages (from-to)172-179
Number of pages8
JournalAnnals of internal medicine
Issue number3
StatePublished - Feb 7 2017

ASJC Scopus subject areas

  • Internal Medicine

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