Medicaid Expansion and Mortality Among Formerly Incarcerated Individuals.

Importance: Most incarcerated individuals eventually return to their communities, where they face high mortality risks that vary by race and ethnicity. The Affordable Care Act allowed states to expand Medicaid to cover all adults aged 18 to 64 years earning up to 138% of the federal poverty level, and expansion has improved health outcomes among the adult population, including mortality; yet research on the formerly incarcerated population remains underdeveloped. Objective: To assess the association between Medicaid expansion and all-cause mortality among formerly incarcerated individuals, including in analyses stratified by race and ethnicity. Design, Setting, and Participants: Cross-sectional study using stacked difference-in-differences (DID) analysis of individual-level prison release data of formerly incarcerated people in 17 states from January 2010 through December 2020 from the Criminal Justice Administrative Records System linked to the Numerical Identification (Numident) file to create a person-month-level dataset. Dates of data analysis were from August 2024 to December 2025. Exposure: Formerly incarcerated individuals released in a Medicaid expansion state. Main Outcomes and Measures: All-cause mortality, determined by month of death in Numident. The study used a discrete-time proportional hazards model fit with logistic regression to implement the DID approach. Odds ratios (ORs) quantifying differences in monthly postrelease mortality risk are reported. The study population was stratified based on race and ethnicity. Results: The study population included 2 210 000 formerly incarcerated people in 17 states: American Indian and Alaska Native (14 500 [0.7%]), Asian (16 500 [0.7%]), Black (655 000 [29.6%]), Hispanic (307 000 [13.9%]), and White (1 220 000 [55.1%]); most were men (79.9%), and the plurality were aged 18 to 34 years (45.0%). Expansion was associated with a 14% lower monthly odds of death in the study population (OR, 0.86; 95% CI, 0.74-0.99; P = .04). In stratified analyses, expansion was associated with a 21% lower odds of monthly mortality among Black individuals (OR, 0.79; 95% CI, 0.68-0.91; P = .002) and a 15% lower odds of monthly mortality among White individuals (OR, 0.85; 95% CI, 0.73-0.99; P = .03); expansion was not associated with mortality among Hispanic individuals (OR, 1.01; 95% CI, 0.71-1.44; P = .95). Conclusions and Relevance: This study found that Medicaid expansion was associated with reduced monthly all-cause mortality after prison release, particularly among Black and White individuals. These findings underscore the importance of extending Medicaid coverage to the reentry population.