Association of Affordable Care Act-related Medicaid expansion with variation in utilization of surgical services

Background: We aim to understand how Medicaid expansion under the ACA has affected utilization of surgical services. Methods: The State Inpatient Databases were used to compare utilization of a broad array of surgical procedures among nonelderly adults (aged 19–64 years) in a multistate population that experienced ACA-related Medicaid expansion to one that did not. We performed a difference-in-differences (DID) analysis to determine the effect of Medicaid expansion on utilization of surgical services from 2012 to 2014. Results: There were 259,061 cases identified in the Medicaid expansion population and 261,269 in the control population. In the expansion group, there was a smaller decrease in utilization - by a margin of 21.68 cases per 100,000 individuals (p < 0.001). Percent of surgical patients covered by Medicaid increased among the expansion group from 12.00% to 15.48% (DID = 3.93%; p < 0.001). Conclusions: Year one of Medicaid expansion under the ACA was associated with a modest but statistically significant difference in utilization of surgical services as well as an increase in percent of surgery patients covered by Medicaid.