Association of Medicaid expansion with children's insurance coverage and healthcare utilization.

Introduction: In 2014, multiple states expanded Medicaid coverage to low-income adults under the Affordable Care Act. We evaluated the association of Medicaid expansion (ME) with children's insurance coverage and health service utilization. Methods: We compared changes in children's insurance coverage and health service utilization between 2010-2013 and 2014-2016 in expansion and non-expansion states. Repeated cross-sectional analysis with linear difference-in-differences (DID) models was conducted using the Medical Expenditure Panel Survey. Results: Medicaid expansion was not associated with changes in the proportion of children with ≥1 month of insurance coverage (DID: -1.9% point [pp], 95% CI -4.1 to 0.3) or the proportion of children with continuous coverage for 12 months (DID: -1.8 pp, 95% CI -5.6 to 2.0). Expansion was not associated with changes in any utilization outcome, including having ≥1 annual well-child visit (DID: -1.9 pp, 95% CI -6.6 to 2.8) or ≥1 annual dental visit (DID: 1.9 pp, 95% CI -2.8 to 6.5). Conclusion: Medicaid expansion was not associated with changes in children's coverage and utilization. While policymakers in states that have not yet expanded Medicaid might still consider doing so for other reasons, findings suggest that alternative interventions will be needed to improve coverage and utilization patterns in children.