ABSTRACT:
Fragmented, expensive, and inequitably accessible, U.S. health service delivery is further impaired by chronic underinvestment in primary care that has eroded care coordination and outcomes. Reforms to strengthen care delivery have been introduced; here, we look to the Medicaid expansion provision of the Affordable Care Act as an example of both expanded coverage and integrated service delivery in the United States.

METHODS:
The study used a mixed-methods approach, employing quantitative analysis of national health center and population data to compare service delivery outcomes in Medicaid expansion and non-expansion states, as well as qualitative interviews with health system stakeholders to provide context.

RESULTS:
The expansion of Medicaid, a public health insurance program for low-income Americans, was associated with substantial improvements in care delivery and health outcomes. Low-income adults in expansion states experienced significantly better access to care. Health centers in expansion states reported greater financial stability and capacity to provide low-cost care. In expansion states, community health centers reported more frequent provision of integrated services over twice as likely to offer medication assisted treatment for opioid use disorder and more likely to report higher rates of provision of behavioral health care and better coordination with social services. During the COVID-19 pandemic, the early adoption of Medicaid expansion was associated with reduced growth in uninsurance. In the earlier period before 2014, early expansion states had approximately a 6% lower all-cause mortality among adults 20–64 compared to non-expansion states.

CONCLUSIONS:
The expansion of coverage and adoption of an integrated approach to service delivery can bolster health system resilience. Medicaid expansion increased access and capacity and provided a buffer. These findings have global importance, as many health systems worldwide face challenges of high costs, gaps in care, and inequities.