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

Abstract

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.

Keywords: Medicaid; Primary care; utilization of services.

Figure 1

Unadjusted Mean Probability of Having Any Office‐Based Visit for Newly Eligible Adults Ages 26–64

1. Notes. Data are from 2008–2014 Medical Expenditure Panel Survey (MEPS). ACA, Affordable Care Act; FPL, federal poverty line; MAGI, modified adjusted gross income. 95% confidence intervals are adjusted for the MEPS complex survey design. Newly eligible are adults aged 26 to 64 with modified adjusted gross income (MAGI) ≤ 138% of FPL who were not pre‐ACA eligible regardless of whether their states expanded eligibility.