Impact of Medicaid Expansion and Firearm Legislation on Cost of Firearm Injuries.

Introduction: Firearm injury-related hospitalizations in the U.S. cost $900 million annually. Before the Affordable Care Act, government insurance programs covered 41% of the costs. This study describes the impact of Affordable Care Act Medicaid expansion and state-level firearm legislation on coverage and costs for firearm injuries.

Methods: This cross-sectional study included 35,854,586 hospitalizations from 27 states in 2013 and 2016. Data analyses were performed in 2022. Firearm injuries were classified by mechanism: assault, unintentional, self-harm, or undetermined. The impact of the Affordable Care Act expansion was determined using difference-in-differences analysis. Differences in per capita costs between states with stronger and weak firearm legislation were compared using univariable and multivariable analyses.

Results: The authors identified 31,451 initial firearm injury-related hospitalizations. In states with weak firearm legislation, hospitalization costs per 100,000 residents were higher from unintentional ($25,834; p=0.04) and self-inflicted ($11,550; p=0.02) injuries; there were no state-level differences in assault or total per capita firearm-related hospitalization costs. Affordable Care Act expansion increased government coverage of costs by 15 percentage points (95% CI=3, 29) and decreased costs to uninsured/self-pay by 14 percentage points (95% CI=6, 21). In 2016, states with weak firearm legislation and no Affordable Care Act expansion had the highest proportion of hospitalization costs attributed to uninsured/self-pay patients (24%, 95% CI=15, 34).

Conclusions: Affordable Care Act expansion increased government coverage of hospitalizations for firearm injuries. Unintentional and self-harm costs were significantly higher for states with weak firearm legislation. States with weak firearm legislation that did not expand Medicaid had the highest proportion of uninsured/self-pay patients.