title: Insurance Expansion and Hospital Emergency Department Access: Evidence From the Affordable Care Act.
abstract: 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.
  
  
  METHODS
  Quasi-experimental observational study from 2012 to 2014.
  
  
  METHODS
  126 investor-owned, hospital-based EDs.
  
  
  METHODS
  Uninsured and Medicaid-insured adults aged 18 to 64 years.
  
  
  METHODS
  ACA expansion of Medicaid in January 2014.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  Results reflect shifts in ED care at investor-owned facilities, which limits generalizability to other hospital types.
  
  
  CONCLUSIONS
  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.
  
  
  BACKGROUND
  Robert Wood Johnson Foundation.
authors.affiliation: From Northwestern University, Evanston, Illinois; Columbia University Mailman School of Public Health, New York, New York; and Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Craig
authors.initials: C
authors.lastname: Garthwaite
authors.affiliation: From Northwestern University, Evanston, Illinois; Columbia University Mailman School of Public Health, New York, New York; and Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Tal
authors.initials: T
authors.lastname: Gross
authors.affiliation: From Northwestern University, Evanston, Illinois; Columbia University Mailman School of Public Health, New York, New York; and Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Matthew
authors.initials: M
authors.lastname: Notowidigdo
authors.affiliation: From Northwestern University, Evanston, Illinois; Columbia University Mailman School of Public Health, New York, New York; and Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: John A
authors.initials: JA
authors.lastname: Graves
mesh_terms: D000293:Adolescent; D000328:Adult; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006297:Health Services Accessibility; D006801:Humans; D065186:Interrupted Time Series Analysis; D008484:Medicaid / Q000331:legislation & jurisprudence*; D017057:Medically Uninsured / Q000706:statistics & numerical data; D008875:Middle Aged; D058991:Patient Protection and Affordable Care Act; D013997:Time Factors; D014195:Travel; D014481:United States