Examination of Elective Bariatric Surgery Rates Before and After US Affordable Care Act Medicaid Expansion

IMPORTANCE: There is limited evidence on whether the Affordable Care Act Medicaid expansion beginning in 2014 improved access to elective procedures. Uninsured individuals are at higher risk of obesity and may have experienced improved uptake of bariatric surgery following Medicaid expansion. OBJECTIVE: To examine the association between Medicaid expansion and the receipt of inpatient elective bariatric surgery among Medicaid-covered and uninsured individuals aged 26 to 64 years. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used difference-in-differences analysis of all-payer data (2010-2017) of 637 557 elective bariatric surgeries for patients aged 26 to 74 years from 11 Medicaid expansion states and 6 nonexpansion states. Nonexpansion states and individuals aged 65 to 74 years were control cohorts. Data analysis was performed from July 6, 2020, to July 23, 2021. EXPOSURE: Living in a Medicaid expansion state. MAIN OUTCOMES AND MEASURES: The main outcomes were the (1) number of elective bariatric surgeries, (2) population count, and (3) rate of bariatric surgery (number of surgeries per 10 000 population) among Medicaid-covered and uninsured individuals. RESULTS: Of the 600 798 elective bariatric surgeries in adults aged 26 to 64 years between 2010 and 2017 from the 17 study states, Medicaid-covered and uninsured individuals accounted for 18.3% of the total surgery volume in expansion states and 14.5% in nonexpansion states. A total of 296 798 patients (78.9%) in expansion states were women vs 177 386 (78.9%) in nonexpansion states. Among individuals aged 26 to 64 years, the median age was 44 (IQR, 37-52) years. Racial and ethnic distribution was non-Hispanic White, 60.2%; non-Hispanic Black, 17.7%; Hispanic, 16.6%; and other, 5.5%. Between 2013 and 2017, the volume of bariatric surgeries for Medicaid-covered and uninsured patients increased annually by 30.3% in expansion states and 16.5% in nonexpansion states. Medicaid expansion was associated with a 36.6% annual increase (95% CI, 8.2% to 72.5%) in surgery volume, a 9.0% annual increase (95% CI, 3.8% to 14.5%) in the population, and a 25.5% change (95% CI, –1.3% to 59.4%) in the rate of bariatric surgery. By race and ethnicity, Medicaid expansion was associated with an increase in the rate of bariatric surgery among non-Hispanic White individuals (31.6%; 95% CI, 6.1% to 63.0%) but no significant change among non-Hispanic Black (5.9%; 95% CI, –19.8% to 39.9%) and Hispanic (28.9%; 95% CI, –24.4% to 119.8%) individuals. CONCLUSIONS AND RELEVANCE: This cohort study found that Medicaid expansion was associated with increased rates of bariatric surgery among lower-income non-Hispanic White individuals, but not among Hispanic and non-Hispanic Black individuals.