How Does the Expansion of Public Insurance Coverage Affect Mortality?: Evidence from Matched Border Counties

We investigate the effects of the expansion of public insurance following the implementation of the Affordable Care Act on mortality rates and mortality rates by cause. Because states that voluntarily chose to expand Medicaid differ economically, and politically from those that did not expand, we employ a empirical design to account for the potential endogeneity of Medicaid coverage – comparing geographically matched border counties. We find that the Medicaid expansion led to small reduction in adult mortality. The reductions occurred entirely for deaths from internal causes, suggesting that increased access to medical care from public insurance coverage is the reason for the mortality decline. We find no change in mortality from external causes, excluding deaths from accidental poisonings. However, we do find that Medicaid expansion led to a very small increase in deaths from accidental poisonings, which include drug overdoses, suggesting that increased access to prescription painkillers from increased public insurance coverage offset, to a small degree, the decline in mortality that otherwise would have occurred.