Perspective:

The authors assessed the effects of Medicaid coverage on low-income, previously uninsured adults, using the gold standard of medical and scientific research: a randomized, controlled trial. In 2008, Oregon used a lottery to allocate a limited number of Medicaid spots for low-income adults (19-64 years of age) to people on a waiting list for Medicaid. The investigators found that the increased health care use from enrollment in Medicaid translates into about a 25% increase in total annual health care expenditures, and also increased the use of preventive care such as mammograms (by 60%) and cholesterol monitoring (by 20%). The authors did not detect a statistically significant change in emergency room utilization. Overall, Medicaid improved financial security and self-reported health. These results question both the optimistic view that Medicaid can reduce health care spending, at least in the short run, and the pessimistic view that Medicaid coverage will not make a difference to the uninsured. Ongoing data collection will provide more information about the longer-run costs and benefits of Medicaid coverage.