Mortality reduced in states that expanded Medicaid

Expansions in eligibility for Medicaid were associated with lower all-cause mortality among adults, according to a new study.

Researchers compared three states that expanded adult Medicaid eligibility (New York, Maine and Arizona) with neighboring states that did not expand coverage (Pennsylvania, New Hampshire, Nevada and New Mexico). The study population was between the ages of 20 and 64 and they were followed for five years before and after the expansions (1997 to 2007). The primary outcome was all-cause mortality, and secondary outcomes were insurance coverage, delaying care because of costs and self-reported health (measured by two large population surveys).

Overall, the population covered by Medicaid expanded by 24.7% in the studied states. That expansion was associated with a 6.1% reduction in mortality, or 19.6 fewer deaths per 100,000 adults. The reductions were greatest among older adults (35- to 64-year-olds), nonwhites and residents of poorer counties. The study also found a 15% decrease in the states' uninsured population, a 21% drop in patients reporting delayed care because of costs, and 3% more patients reporting excellent or very good health. The results were published by the New England Journal of Medicine on July 25.

The improvements in the secondary outcomes may not be sufficient to account for the large change in mortality, the researchers acknowledged. The 6% drop in mortality could be achieved if Medicaid coverage reduced mortality risk by 30% and the 1-year risk of death were 1.9%, they calculated. This would indicate that the new Medicaid enrollees were sicker than the general population, a finding that was supported by new enrollees being older, more likely to be minorities and more likely to be in fair or poor health.

However, the study was limited by its nonrandomized design and so cannot prove causality, the authors cautioned. Insurance coverage also increased during the study period in non-Medicaid populations and mortality declined (to a lesser degree) among the elderly. Another limitation is that the results were largely driven by the largest included state, New York. Still, the authors concluded that expansion of Medicaid coverage may reduce mortality among adults, and they urged policymakers to be aware of this effect when making changes to the insurance program.