Medicaid Expansion May Be Associated with Lower Mortality Rates

December 20, 2021 - States that implemented Medicaid expansion saw reductions in all-cause mortality rates compared to nonexpansion states, a study from the Keck School of Medicine at the University of Southern California (USC) found.

The Affordable Care Act authorized states to expand their Medicaid programs in 2014, but as of 2021, 12 states have yet to expand.

Past studies have shown that Medicaid expansion may increase access to healthcare coverage and improve certain outcomes including maternal health outcomes.

Researchers from USC looked at all reported deaths among adults aged 25 to 64 between January 1, 2010 and December 31, 2018—data that they obtained from the Wide-ranging Online Data for Epidemiologic Research database through the Centers for Disease Control and Prevention (CDC).

Researchers compared the mortality rates in states that have expanded Medicaid to nonexpansion states.

The study data included 31 expansion states and Washington DC and 17 nonexpansion states. Virginia, Utah, Maine, and Idaho expanded their Medicaid programs in 2019 or 2020 but were included as nonexpansion states as the study period ended in 2018. Additionally, Massachusetts and Wisconsin had Medicaid expansions independent of the Affordable Care Act and were excluded from the analysis.

Medicaid expansion states had lower mortality rates compared to nonexpansion states, the results revealed. All-cause mortality was 311 per 100,000 adults in expansion states and 365 per 100,000 adults in nonexpansion states. Expansion states also had 11 fewer deaths per 100,000 adults per year than nonexpansion states.

Specifically, Medicaid expansion states saw fewer cardiovascular-related and respiratory-related deaths per 100,000 adults per year and fewer deaths with internal causes per 100,000 adults per year, the study noted.

Medicaid expansion can increase access to coverage and care, including specialty care, a previous study has suggested.

Mortality rate reductions were associated with certain population characteristics as well. In 2010, prior to expansion, expansion state populations had fewer non-Hispanic Black individuals and more non-Hispanic white individuals compared to nonexpansion states. Expansion states also had smaller rural populations and fewer uninsured individuals than nonexpansion states.

These characteristics may have contributed to the differences in mortality rates.

For each percentage point increase in non-Hispanic Black residents across the study period, there was 1 fewer death per 100,000 adults. For each percentage point increase in women residents, there were 17 fewer deaths per 100,000 adults.

“The reduction in all-cause mortality was most associated with the number of women and non-Hispanic Black residents in each state,” Brian Lee, MD, assistant professor of clinical medicine at the Keck School of Medicine, stated in a press release. “States that have chosen not to expand [Medicaid] have higher proportions of poor and Black residents, so they may have the most to gain from adopting Medicaid expansion.”

Women and Black individuals tend to have higher rates of poverty, lower rates of health coverage, and higher premiums compared to men and individuals of other racial backgrounds, indicating that they could benefit from Medicaid expansion.

The number of uninsured residents also impacted mortality rates, with 5 fewer deaths per 100,000 adults for each percentage point decrease in the proportion of uninsured individuals between 2014 and 2018.

This suggests that Medicaid expansion is associated with a lower mortality rate mainly because it provides healthcare coverage to more people. From 2010 to 2018, expansion states saw a greater reduction in the share of uninsured individuals compared to nonexpansion states, according to the study.

Overall, Medicaid expansion was associated with reductions in mortality rates, with specific populations benefitting the most.

“Continued Medicaid expansion may be a tool for policymakers to address ongoing wealth- and race-disparities, providing a ladder to improved health outcomes and social mobility for these underserved populations,” Lee concluded.