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The Effects of the Affordable Care Act Medicaid Expansions on Out-Of-Pocket Spending, Healthcare Utilization, and Health Outcomes


It is well documented that lack of health insurance negatively affects access to care and health outcomes. Uninsured people are less likely, compared to those with health insurance, to have usual source of care and receive necessary care primarily due to the cost, leading to detrimental health consequences. The Medicaid expansions under the Patient Protection and Affordable Care Act (ACA) were intended to provide access to health insurance coverage for many of the more than 45 million uninsured Americans. This major policy change originally required all states to expand the eligibility of their Medicaid programs to those younger than 65 years with incomes up to 138% of the federal poverty level (FPL), based solely on income without regard to categorical eligibility status. To date, there is ample evidence that the percentage of the uninsured has been significantly reduced nationally despite the fact that 14 states have not adopted the ACA Medicaid expansions as of August 2019 due to the 2012 Supreme Court ruling making those expansions voluntary rather than mandatory.

This dissertation assessed the further effects of the ACA Medicaid expansions on out-of-pocket spending, healthcare utilization, and health outcomes for chronic conditions using a nationally representative sample of the low-income non-elderly population from the 2010-2016 Medical Expenditure Panel Survey and 2005-2016 National Health and Nutrition Examination Survey. It took advantage of the natural experiment that allowed a comparison of changes in outcomes between the expansion and non-expansion states. The three studies found that the ACA Medicaid expansions were associated with reduced out-of-pocket spending and improved financial risk protection, a modest increase in primary care physician visits without any meaningful change in emergency department visits, and improved clinical measures for hypertension and diabetes (but no improvement in outcomes for hyperlipidemia and depression), during the three years after the policy implementation.

The findings suggest that the ACA has been successful in achieving its goals of removing financial barriers, promoting access to primary care, and improving population health among low-income uninsured Americans. It has important implications for state decisions on adopting the ACA Medicaid expansions and for the ongoing national debate over the repeal of the ACA, including the Medicaid expansions.

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