Craig Garthwaite, PhD; Tal Gross, PhD; Matthew Notowidigdo, PhD; John A. Graves, PhD
Portions of this work were presented at the 2015 Summer Institute at the National Bureau of Economic Research and the 2016 American Economic Association annual meetings.
Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the Robert Wood Johnson Foundation.
Acknowledgment: The authors thank Pranita Mishra and Claire Posey for their technical programming and administrative support. These contributors received no compensation apart from usual salary for their contributions.
Grant Support: By the Robert Wood Johnson State Health Access Reform Evaluation program (72183).
Disclosures: Authors have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M16-0086.
Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer and Johnson & Johnson.
Reproducible Research Statement:Study protocol: Not available. Statistical code: Available from Dr. Graves (e-mail, email@example.com). Data set: Because of data use agreements with participating hospital chains, the underlying data used for this project are not available. However, the data extracts were based on data elements submitted to the Health Care Cost and Utilization Project. The Health Care Cost and Utilization Project data are available to researchers through the Agency for Healthcare Research and Quality at www.ahrq.gov/research/data/hcup/index.html.
Requests for Single Reprints: John A. Graves, PhD, Department of Health Policy, Vanderbilt University School of Medicine, 2525 West End Avenue, Suite 1200, Nashville, TN 37203; e-mail, firstname.lastname@example.org.
Current Author Addresses: Dr. Garthwaite: Northwestern Kellogg School of Management, Strategy Department, 2001 Sheridan Road, Evanston, IL 60208.
Dr. Gross: Columbia University Mailman School of Public Health, Department of Health Policy and Management, Columbia University, 722 West 168th Street, Room 485, New York, NY 10032.
Dr. Notowidigdo: Northwestern University, Department of Economics, 2001 Sheridan Road, Evanston, IL 60208.
Dr. Graves: Department of Health Policy, Vanderbilt University School of Medicine, 2525 West End Avenue, Suite 1200, Nashville, TN 37203.
Author Contributions: Conception and design: C. Garthwaite, T. Gross, M. Notowidigdo, J.A. Graves.
Analysis and interpretation of the data: C. Garthwaite, T. Gross, M. Notowidigdo, J.A. Graves.
Drafting of the article: C. Garthwaite, T. Gross, M. Notowidigdo, J.A. Graves.
Critical revision of the article for important intellectual content: T. Gross, M. Notowidigdo, J.A. Graves.
Final approval of the article: C. Garthwaite, T. Gross, M. Notowidigdo, J.A. Graves.
Statistical expertise: C. Garthwaite, T. Gross, J.A. Graves.
Obtaining of funding: T. Gross.
Administrative, technical, or logistic support: T. Gross, J.A. Graves.
Collection and assembly of data: T. Gross, J.A. Graves.
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).
To investigate the effect of the 2014 ACA Medicaid expansion on the location, insurance status, and type of ED visits.
Quasi-experimental observational study from 2012 to 2014.
126 investor-owned, hospital-based EDs.
Uninsured and Medicaid-insured adults aged 18 to 64 years.
ACA expansion of Medicaid in January 2014.
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.
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.
Results reflect shifts in ED care at investor-owned facilities, which limits generalizability to other hospital types.
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.
Robert Wood Johnson Foundation.
Garthwaite C, Gross T, Notowidigdo M, Graves JA. Insurance Expansion and Hospital Emergency Department Access: Evidence From the Affordable Care Act. Ann Intern Med. ;166:172–179. doi: 10.7326/M16-0086
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Published: Ann Intern Med. 2017;166(3):172-179.
Published at www.annals.org on 20 December 2016
Emergency Medicine, Hospital Medicine.
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