Medicaid Increases Emergency-Department Use: Evidence from Oregon's Health Insurance Experiment

• Published in: Science (American Association for the Advancement of Science) Vol. 343; no. 6168; pp. 263 - 268
• Main Authors: Taubman, Sarah L., Allen, Heidi L., Wright, Bill J., Baicker, Katherine, Finkelstein, Amy N.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 17-01-2014; The American Association for the Advancement of Science
• Subjects: Adult; Ambulatory Care - statistics & numerical data; Emergency departments; Emergency medical care; Emergency Service, Hospital - utilization; Female; Health care policy; Health insurance; Health outcomes; Hospital admissions; Hospitals; Humans; Inpatients - statistics & numerical data; Insurance coverage; Insurance, Health; Male; Medicaid; Medicaid - economics; Medically Uninsured; Oregon; P values; Poverty; Primary health care; Random allocation; RESEARCH ARTICLE; Self reports; United States; Oregon; United States
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1246183

In 2008, Oregon initiated a limited expansion of a Medicaid program for uninsured, low-income adults, drawing names from a waiting list by lottery. This lottery created a rare opportunity to study the effects of Medicaid coverage by using a randomized controlled design. By using the randomization provided by the lottery and emergency-department records from Portland-area hospitals, we studied the emergency department use of about 25,000 lottery participants over about 18 months after the lottery. We found that Medicaid coverage significantly increases overall emergency use by 0.41 visits per person, or 40% relative to an average of 1.02 visits per person in the control group. We found increases in emergency-department visits across a broad range of types of visits, conditions, and subgroups, including increases in visits for conditions that may be most readily treatable in primary care settings.