Arizona, Maine, and New York significantly expanded Medicaid coverage in the early 2000s. That expansion appears to have reduced death rates, according to a new study in the New England Journal of Medicine.
Benjamin Sommers, Katherine Baicker, and Arnold Epstein, all of the Harvard School of Public Health, compared mortality in those states to four neighboring states (Nevada and New Mexico; New Hampshire; and Pennsylvania) that didn’t expand Medicaid coverage. They found that mortality fell in the three states that expanded coverage even as it increased in the neighbors:
The authors use the usual battery of statistical techniques to try to tease our whether some other factors, perhaps changing economic fortunes or demographics, might explain the mortality differences. After all that, their best guess is that the reduction in death rates is real: on average, one death was averted each year for every 176 extra adults covered by Medicaid.
The study does have limitations, as the authors carefully note. For example, it relies on mortality data for counties. What you’d really like, of course, are data for individuals, so you could track the impacts of Medicaid enrollment person-by-person.
For further discussion, see this NYT article by Pam Belluck.