Expansion of insurance under the affordable care act and invasive management of acute myocardial infarction.

Background The Affordable Care Act of 2010 extended health insurance through expansion of Medicaid and subsidies for commercial insurance. Prior work has produced differing results in associating expanded insurance with improvements in health care processes and outcomes. Evaluating specific mechanisms of care processes and their association with insurance expansion may help reconcile those results. Methods and results We used inpatient hospitalization data in the Nationwide Inpatient Sample (NIS) Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality from 1/1/2008 to 9/30/2015. We included all hospitalizations for acute myocardial infarction (AMI). As a primary outcome, we defined percent rate of AMI hospitalizations receiving percutaneous coronary intervention (PCI) per month. In the non-Medicare (intervention) group, there was a relative decrease of 0.2% of the monthly trend before and after expansion (95% CI [-0.3%, -0.1%]). In the Medicare group, there was a relative decrease of 0.1% of the monthly trend before and after expansion (95% CI [-0.2%, 0%]). Conclusions We did not detect a relative difference in PCI for AMI associated with insurance expansion under health reform.