Association of Medicaid Expansion with Cardiovascular Mortality

Abstract

Importance: Medicaid expansion under the Patient Protection and Affordable Care Act led to one of the largest gains in health insurance coverage for nonelderly adults in the United States. However, its association with cardiovascular mortality is unclear. Objective: To investigate the association of Medicaid expansion with cardiovascular mortality rates in middle-aged adults. Design, Setting, and Participants: This study used a longitudinal, observational design, using a difference-in-differences approach with county-level data from counties in 48 states (excluding Massachusetts and Wisconsin) and Washington, DC, from 2010 to 2016. Adults aged 45 to 64 years were included. Data were analyzed from November 2018 to January 2019. Exposures: Residence in a Medicaid expansion state. Main Outcomes and Measures: Difference-in-differences of annual, age-adjusted cardiovascular mortality rates from before Medicaid expansion to after expansion. Results: As of 2016, 29 states and Washington, DC, had expanded Medicaid eligibility, while 19 states had not. Compared with counties in Medicaid nonexpansion states, counties in expansion states had a greater decrease in the percentage of uninsured residents at all income levels (mean [SD], 7.3% [3.2%] vs 5.6% [2.7%]; P