Disappearing Medicaid enrollment disparities for US citizen children in immigrant families: State level trends from 2008-2015.

OBJECTIVE: Medicaid and the Children's Health Insurance Program (CHIP) provide health insurance to 38% of all children in the United States. Uninsured rates continued to fall over the past decade, and citizen children in immigrant families experienced the most dramatic gains. Our objective is to test whether states have managed to close Medicaid enrollment gaps between U.S. citizen children in native and immigrant families.

METHODS: We use the 2008-2015 American Community Surveys to compare uninsured rates for 2.4 million Medicaid-eligible citizen children in immigrant and native families. State fixed-effects probit models estimate the probability of children remaining uninsured when eligible for public coverage, excluding children covered by private insurance. We compare the states with the largest enrollment gains across differences in policies relevant to CHIP/Medicaid participation for all children, including CHIP Reauthorization Act (CHIPRA) enrollment simplification, Immigrant Children's Health Improvement Act (ICHIA), and Affordable Care Act (ACA) Medicaid expansion.

RESULTS: Most states reduced their enrollment disparities by half or even completely eliminated their enrollment differentials. However, the states with the largest gains did not adopt ACA and CHIPRA policy options that would have improved CHIP/Medicaid participation for children in their states - or implemented the policies long before the observed gains.

CONCLUSIONS: Rather than policy anchoring the gains, the improvements may be rooted in operational changes and outreach efforts during CHIPRA and ACA implementation. Absent a policy anchor, the large enrollment differentials of a decade ago may reappear for children in immigrant families, affect the wellbeing of children and their communities.