We examine the effect of Medicaid expansion on reimbursement for emergency physicians’ professional services.

We conducted a retrospective study using data from a national emergency medicine group in a sample of 50 emergency departments (EDs) from July 1, 2012, to June 30, 2015. We categorized facilities in 14 states into full-expansion (23), partial-expansion (17), and nonexpansion (10) categories based on pre-expansion Medicaid eligibility criteria for all adults. We used a difference-in-differences design to assess the effect of Medicaid expansion on provider reimbursement per visit. Secondary outcomes included reimbursement per relative value unit and relative value units per visit, both overall and by payer type, controlling for age, sex, billing codes, and health system relationship.

We studied greater than 6.7 million ED visits during July 2012 to December 2015, 3.0 million pre-expansion and 3.7 million postexpansion. After adjusting for covariates, reimbursement per visit increased 6.3% (95% confidence interval 1.4% to 11.1%) in full-expansion relative to nonexpansion states and did not change significantly in partial-expansion versus nonexpansion states. Reimbursement per visit for commercial insurance increased 17.1% (95% confidence interval 9.9% to 24.2%) in full-expansion versus nonexpansion states. Reimbursement for self-pay visits increased 9.7% (95% confidence interval 3.7% to 15.7%) in full-expansion versus nonexpansion states. Changes in payments were driven by higher reimbursement per relative value unit; relative value units per visit declined slightly in full-expansion compared with nonexpansion states.

In this sample, full Medicaid expansion increased payments for emergency physicians’ professional services compared with reimbursement in nonexpansion states. Higher reimbursement was driven primarily by lower proportions of uninsured patients and increased reimbursement per visit for both commercially insured and self-pay patients in states with full Medicaid expansion.