The Patient Protection and Affordable Care Act (ACA, P.L. 111-148, as amended) made a number of changes to Medicaid. Perhaps the most widely discussed is the expansion of eligibility to adults with incomes up to 138 percent of the federal poverty level (FPL). Originally a requirement, the Supreme Court ruling in June 2012 effectively made the Medicaid expansion an option. To date, more than half of states have opted to expand.
Beyond the Medicaid expansion, the ACA sought to increase the number of Americans with health insurance by providing new premium tax credits for the purchase of private health insurance and made a number of reforms to the private insurance market, such as eliminating preexisting condition exclusions and establishing annual limits on out-of-pocket costs. The law also allowed young adults to remain on their parents’ insurance plans up to age 26 and required most individuals to secure minimum essential coverage.
Other Medicaid and CHIP provisions in the ACA include a maintenance-of-effort requirement that prevented states from reducing eligibility below that in place on the date the ACA was enacted. The provision was in effect until 2014 for adults and remains through fiscal year (FY) 2019 for children. The ACA also aligned states’ minimum Medicaid eligibility threshold for children at 138 percent FPL, requiring some states to shift older children from separate CHIP programs into Medicaid. Prior to the ACA, the mandatory eligibility levels for children in Medicaid differed by age: States were required to cover infants and children between the ages of 1 and 5 in Medicaid up to 133 percent FPL and children between the ages of 6 and 18 up to 100 percent FPL. 
The ACA also included provisions to streamline eligibility, enrollment, and renewal processes, for example, by requiring a single application for Medicaid, CHIP, and subsidized exchange coverage. In part due to these changes, enrollment and spending in Medicaid has increased in all states, regardless of whether the state expanded coverage to non-disabled adults.
The ACA also included reductions in federal funds for disproportionate share hospital (DSH) supplemental payments under the assumption that increased coverage would lead to a decline in uncompensated care. These reductions have been delayed a number of times and are currently scheduled to go into effect in FY 2018.
Learn more about how Medicaid interacts with the ACA:
- Medicaid expansion to the new adult group
- Medicaid enrollment changes following the ACA
- Changes in coverage and access
- State and federal spending under the ACA
- Hospitals and other providers