Impact of Recent Medicaid Expansions on Office-Based Primary Care and Specialty Care among the Newly Eligible.

OBJECTIVE: To quantify the effect of Medicaid expansions on office-based care among the newly eligible.

DATA SOURCE: 2008-2014 Medical Expenditure Panel Survey.

STUDY DESIGN: The main sample is adults age 26-64 with incomes ≤138% of poverty who were not eligible for Medicaid prior to the Affordable Care Act. For this population, difference-in-differences linear probability models compare utilization between expansion and nonexpansion states and between 2008-2013 and 2014.

EXTRACTION METHODS: Medicaid eligibility is simulated using data on family relationships, state of residence, and income.

PRINCIPAL FINDINGS: Relative to comparable adults in nonexpansion states, newly eligible adults in expansion states were 9.1 percentage points more likely to have any office-based primary care physician visit in 2014, a 21.4% increase from 2013 (p-value = .004); 6.9 percentage points more likely to have a specialist visit, a 25.2% increase from 2013 (p-value = .036); and 5.1 percentage points more likely to have a visit with a nurse practitioner, nurse, or physician assistant, a 34.5% increase from 2013 (p-value = .016).

CONCLUSIONS: State Medicaid expansions in 2014 were associated with greater likelihoods of visits with a variety of office-based providers. The estimated effects are larger among newly eligible compared with previous estimates on broader populations of low-income adults.