Early Impact of the Affordable Care Act Coverage Expansion on Safety-Net Hospital Inpatient Payer Mix and Market Shares

Abstract

Objective: To examine the impact of the Affordable Care Act's coverage expansion on safety-net hospitals (SNHs). Study Setting: Nine Medicaid expansion states. Study Design: Differences-in-differences (DID) models compare payer-specific pre-post changes in inpatient stays of adults aged 19–64 years at SNHs and non-SNHs. Data Collection Methods: 2013–2014 Healthcare Cost and Utilization Project State Inpatient Databases. Principal Findings: On average per quarter postexpansion, SNHs and non-SNHs experienced similar relative decreases in uninsured stays (DID = –2.2 percent, p =.916). Non-SNHs experienced a greater percentage increase in Medicaid stays than did SNHs (DID = 13.8 percent, p =.041). For SNHs, the average decrease in uninsured stays (–146) was similar to the increase in Medicaid stays (153); privately insured stays were stable. For non-SNHs, the decrease in uninsured (–63) plus privately insured (–33) stays was similar to the increase in Medicaid stays (105). SNHs and non-SNHs experienced a similar absolute increase in Medicaid, uninsured, and privately insured stays combined (DID = –16, p =.162). Conclusions: Postexpansion, non-SNHs experienced a greater percentage increase in Medicaid stays than did SNHs, which may reflect patients choosing non-SNHs over SNHs or a crowd-out of private insurance. More research is needed to understand these trends.