Abstract 3: Association of Medicaid Expansion with Cardiovascular Mortality - A Quasi-experimental Analysis
Authors: Khatana Sameed Ahmed M , Bhatla Anjali , Nathan Ashwin S , Giri Jay , Shen Changyu , Kazi Dhruv S , Yeh Robert W , Groeneveld Peter W 
Published: April 2019

Background:
Medicaid expansion under the Affordable Care Act (ACA) led to one of the largest gains in health insurance coverage for non-elderly adults in the US. However, its impact on health outcomes is unclear. We aimed to study whether trends in cardiovascular mortality for middle-aged adults differed between states that did and did not expand Medicaid.

Methods:
Using the CDC Wide-ranging Online Data for Epidemiologic Research mortality database, we obtained county-level, age-adjusted, cardiovascular mortality rates for all individuals 45 to 64 years of age from 2010 to 2016 for all states except Massachusetts and Wisconsin (due to non-ACA related Medicaid expansion in these two states). We used a differences-in-differences (DID) approach to measure differences in cardiovascular morality rates between states, based on Medicaid expansion status, before and after expansion. The DID estimator was adjusted for percentage of residents who were female, African-American, Hispanic, percentage of residents living in poverty, county unemployment rate, median household income, number of primary care providers per 100,000 residents, number of cardiologists per 100,000 residents, metropolitan vs. non-metropolitan county classification, and percentage of low-income residents with health insurance in 2010.

Results:
A total of 1960 counties were included. As of 2016, 29 states and DC had expanded Medicaid eligibility, while 19 states had not. Compared with counties in non-expansion states, counties in expansion states had a greater increase in health insurance coverage for low-income residents [19.8% (SD = 5.5) vs. 13.5% (SD = 3.9); p <0.001]. Pre-expansion there were no significant differences in trends in mortality rates. Counties in expansion states had a significantly smaller increase in cardiovascular mortality rates [141.9 (95% CI 135.6, 148.3) to 142.0 (95% CI 135.5, 148.6) deaths per 100,000 residents per year] compared to counties in non-expansion states [176.1 (95% CI 169.3, 182.8) to 180.6 (95% CI 173.2, 188.0) deaths per 100,000 residents per year]. After accounting for differences in demographic and economic variables, counties in expansion states had 4.0 (95% CI 2.1, 6.0) fewer deaths per 100,000 residents per year from cardiovascular causes after expansion, compared to if they had followed the same trends as counties in non-expansion states. This effect was more prominent in non-metropolitan counties and in counties in the top 50
th
percentile for residents living in poverty.

Conclusion:
Counties in Medicaid expansion states had a significantly smaller increase in cardiovascular mortality rates among non-elderly adults compared with counties in non-expansion states. Our findings suggest that Medicaid expansion was associated with a beneficial effect on cardiovascular mortality and may be an important consideration for states debating expansion of Medicaid eligibility.