A brand new NBER working paper led by Sarah Miller just came out this morning
Our analysis compares changes in mortality for near-elderly adults in states with and without Affordable Care Act Medicaid expansions. We identify adults most likely to benefit using survey information on socioeconomic and citizenship status, and public program participation. We find a 0.13 percentage point decline in annual mortality, a 9.3 percent reduction over the sample mean, associated with Medicaid expansion for this population. The effect is driven by a reduction in disease-related deaths and grows over time. We find no evidence of differential pre-treatment trends in outcomes and no effects among placebo groups.
They follow a cohort of people who were between 55 and 64 in 2014 through 2017. They matched these individuals against death certificates. The decision by the Supreme Court to allow states to choose to expand or not expand Medicaid to the 138% FPL group created variation in geography and timing that the researchers leveraged.
In the first year following the coverage expansion, the probability of mortality declined by about 0.09 percentage points, or 6.4 percent relative to the sample mean. The estimated impact of the expansions increases over time, suggesting that prolonged exposure to Medicaid results in increasing health improvements. By year 4, residents of expansion states have an annual mortality rate that is 0.2 percentage points lower than their non-expansion state counterparts. In our supplemental analysis
using the MDAC data, we find evidence that healthcare amenable and internal causes of death were reduced by the expansions, but no evidence that deaths due to external causes, such as car accidents, fell.
There probably is a dosing effect and a population vulnerability effect. Longer Medicaid Expansion probably saves more lives than a short expansion. This is important as the Oregon Medicaid study looked at only health outcomes over one or two years. The QJE paper on Oregon only looked at about 14 months worth of coverage instead of the potential for several years of coverage. The other big difference is that this NBER paper is looking at a subgroup (55-64 year olds) that is much older on average than the group that the Oregon study examined (mostly 20-50 year olds (73% of sample)). The NBER paper used the Oregon Health study’s public use data (awesome for replication and validity checks) for the same subset and found large but not statistically significant mortality changes as well. Age is a good predictor of general mortality risk. Higher risk groups should show mortality differences more readily than lower risk groups for a given intervention.
This working paper is showing that Medicaid expansion has significant mortality impacts for a population that is likely to have fairly high mortality rates. They estimate that the decision to not expand Medicaid has led to 15,000 excess deaths for this subgroup.
Medicaid matters. It improves financial wellbeing, improves mental health and lowers mortality rates.