Impact of the Affordable Care Act Insurance Marketplaces on Out-of-Pocket Spending Among Surgical Patients.

OBJECTIVE: To evaluate the association between the introduction of the Affordable Care Act (ACA) Health Insurance Marketplaces ("Marketplaces") and financial protection for patients undergoing surgery. BACKGROUND: The ACA established Marketplaces through which individuals could purchase subsidized insurance coverage. However, the effect of these Marketplaces on surgical patients' healthcare spending remains largely unknown. METHODS: We analyzed a nationally representative sample of adults aged 19-64 who underwent surgery in 2010-2017, using the Medical Expenditure Panel Survey. Low-income patients eligible for cost-sharing and premium subsidies in the Marketplaces [income 139%-250% federal poverty level (FPL)] and middle-income patients eligible only for premium subsidies (251%-400% FPL) were compared to high-income controls ineligible for subsidies (>400% FPL) using a quasi-experimental difference-in-differences approach. We evaluated 3 main outcomes: (1) out-of-pocket spending, (2) premium contributions, and (3) likelihood of experiencing catastrophic expenditures, defined as out-of-pocket plus premium spending exceeding 19.5% of family income. RESULTS: Our sample included 5450 patients undergoing surgery, representing approximately 69 million US adults. Among low-income patients, Marketplace implementation was associated with $601 lower [95% confidence interval (CI): -$1169 to -$33; P = 0.04) out-of-pocket spending; $968 lower (95% CI: -$1652 to -$285; P = 0.006) premium spending; and 34.6% lower probability (absolute change: -8.3 percentage points; 95% CI: -14.9 to -1.7; P = 0.01) of catastrophic expenditures. We found no evidence that health expenditures changed for middle-income surgical patients. CONCLUSIONS: The ACA's insurance Marketplaces were associated with improved financial protection among low-income surgical patients eligible for both cost-sharing and premium subsidies, but not in middle-income patients eligible for only premium subsidies.