The effects of expanding public insurance to rural low-income childless adults.

OBJECTIVE: This study measures the change in health care use after enrollment into a new public insurance program for low-income childless adults.

DATA SOURCES/STUDY SETTING: The data sources include claims from a large integrated health system in rural Wisconsin and Medicaid enrollment files, January 2007-September 2012.

STUDY DESIGN: We employ a regression discontinuity design to measure the causal effect of public insurance enrollment on counts of outpatient, emergency department, and inpatient events for 2 years following enrollment for a sample of previously uninsured low-income adults in rural Wisconsin.

PRINCIPAL FINDINGS: Public insurance enrollment led to substantial increases in outpatient visits including preventive visits, but not mental health visits. Public insurance enrollment also led to increases in inpatient stays, but the study is inconclusive on whether it led to an increase in ED visits.

CONCLUSIONS: Public insurance expansions to childless adults have the potential to impact the use of health care. The large increase in Medicaid coverage and reduction in rates of uninsurance anticipated to result from the Affordable Care Act should increase the use of inpatient and outpatient services, but they will have an uncertain impact on the use of ED among rural populations.