2104. Effect of the Affordable Care Act on the Use of Emergency Room Medical Imaging
Authors * Denotes Presenting Author
  1. Neal Gupta *; Thomas Jefferson University Hospital
The Affordable Care Act (ACA), implemented in 2014, allowed nearly 17 million Americans to obtain health insurance. One objective of extending health coverage to the previously uninsured was to decrease the use of emergency room services. It is estimated up to 30% of ER visits are non-urgent and could be managed in the outpatient setting. However, the only randomized controlled trial ever to examine the impact of health insurance on ER use, the Oregon Health Insurance Experiment, suggested ER visits actually increased following the expansion of healthcare coverage. We conducted a retrospective, uncontrolled, before and after study to examine the impact of the ACA on the use of diagnostic imaging in the emergency room.

Materials and Methods:
We performed a secondary analysis using data from the The National Hospital Ambulatory Medical Care Survey (NHAMCS). Performed by the Centers for Disease Control, this survey of hospitals provides nationwide estimates of ER utilization. From the Emergency Department Table Summaries, we were able to tabulate the total number of ER visits and total number of ER visits utilizing any form of imaging for each year between 2009-2017. Given the way the survey instrument reports specific modalities, we tabulated the number of ER visits utilizing MRI, US and CT only for the years 2014-2017. We calculated the average percentage of ER visits involving any medical imaging between 2009-2014 (before the ACA was enacted) and between 2014-2017 (after the ACA was enacted). Its significance difference was determined via a student t-test. Additionally, we calculated the percentage change in ER visits involving CT, MRI and US for the years between 2014-2017. We expect the percentage of ER visits utilizing diagnostic imaging to decline after the implementation of the ACA, reflecting imaging being re-directed to the outpatient setting.

Between 2009-2017, the NHAMCS estimated there were 1,226,365,000 nationwide emergency room visits. Before the ACA was implemented, 46% of ER visits involved medical imaging and afterwards 48% involved any form of imaging - a difference that is not statistically significant (P=0.17). Between 2014-2017, the percentage of ER visits involving any form of imaging increased by 4.5%. Additionally, the percentage of ER visits utilizing radiographs, ultrasound, CT and MRI increased 3.1%, 1.6%, 4.4% and 0.3% respectively.

No association between decreasing ER imaging utilization and the implementation of the ACA is found. Our study is limited by the absence of a control group, which does not allow us to account for secular trends that may be affecting the use of imaging studies. However, it does draw on the strength of the NHAMCS, a data set that includes all insurance payers and nationwide data, to suggest that the net effect on ER imaging utilization remains unchanged after the passage of the ACA. Furthermore, there does appear to be small but increasing trends in the use of medical imaging in the ER. Overall, this suggests ER imaging use is not significantly being redirected to the outpatient setting.