What is Medicaid's Impact on Access to Care, Health Outcomes, and Quality of Care? Setting the Record Straight on the Evidence

Medicaid, the nation’s main public health insurance program for low-income people, now covers over 65 million Americans – more than 1 in every 5 – at least some time during the year. The program’s beneficiaries include many of the most disadvantaged individuals and families in the U.S. in terms of poverty, poor health, and disability. The Affordable Care Act (ACA) provided for a broad expansion of Medicaid to cover millions of low-income uninsured adults whom the program has historically excluded. However, as a result of the Supreme Court’s decision on the ACA, the Medicaid expansion is, in effect, a state option. Almost half the states are moving forward with the Medicaid expansion. But the others, which are home to half the uninsured adults who could gain Medicaid coverage under the ACA, have decided not to expand Medicaid at this time or are still debating the issue.

Controversy about the Medicaid expansion has been stoked by an assertion that first appeared in a Wall Street Journal editorial a couple of years ago and has since resurfaced periodically, that “Medicaid is worse than no coverage at all.”^{1 2 3 4 5 6} This claim about Medicaid is sharply at odds with the authoritative findings of the Institute of Medicine (IOM) Committee on Consequences of Uninsurance, detailed in Care Without Coverage: Too Little, Too Late, the second of six reports the IOM issued on the subject in the early 2000’s.⁷ Based on a comprehensive review of the research examining the impact of health insurance on adults, the IOM charted the causal pathway from coverage to better health outcomes, concluding:

Health insurance coverage is associated with better health outcomes for adults. It is also associated with having a regular source of care and with greater and more appropriate use of health services. These factors, in turn, improve the likelihood of disease screening and early detection, the management of chronic illness, and effective treatment of acute conditions such as traumatic brain injury and heart attacks. The ultimate result is improved health outcomes.

In light of Medicaid’s large and growing coverage role, and the significant health care needs of its beneficiaries, an evidence-based assessment of the program’s impact on access to care, health outcomes, and quality of care is of major interest. Such an assessment would also be helpful given perennial concerns about insufficient physician participation in Medicaid, generally attributed to low fees paid by state Medicaid programs. Since Medicaid was established nearly 45 years ago, a large body of research on and analysis of the program has accumulated. After first reviewing the purpose of health insurance and the distinctive profile of the Medicaid population – both considerations that lend important context to the research findings – this brief takes a look at what the literature shows overall regarding the difference Medicaid makes.