Medicaid expansion and infant mortality, revisited: A difference-in-differences analysis

Objective To determine the association between Medicaid expansion and infant mortality rate (IMR) in the United States. Data Sources State-level aggregate data on US IMR, race, and sex were abstracted from the US Center for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research. Study Design The association between Medicaid expansion and IMR adjusted for race and sex was assessed with multiple linear regression models using difference-in-differences estimation and Huber-White robust standard errors. Principal Findings Difference-in-differences regression found no association between Medicaid expansion status and change in national IMR from 2010 to 2017 (Coef. = 0.04; 95% CI: -0.39, 0.46). However, among Hispanics, the program was found to be associated with reduction in IMR (Diff-in-Diff Coef. = -0.53; 95% CI: -1.02, -0.03). Conclusions Overall, the Affordable Care Act-induced Medicaid expansion was not associated with IMR reduction in expansion states relative to nonexpansion states. However, the program was associated with a significant IMR decline among Hispanics.