Contemporary national trends and disparities for head CT use in emergency department settings: Insights from National Hospital Ambulatory Medical Care Survey (NHAMCS) 2007–2017

Background: The exponential growth in CT utilization in emergency department (ED) until 2008 raised concerns regarding cost and radiation exposure. Head CT was one of the commonest studies. This led to mitigating efforts such as appropriate use guidelines, policy and payment reforms. The impact of these efforts is not fully understood. In addition, disparities in outcomes of acute conditions presenting to the ED is well known however recent trends in imaging utilization patterns and disparities are not well understood. In this study, we describe nationwide trends and disparities associated with head CT in ED settings between 2007 and 2014. Methods: We analyzed 2007–2017 National Hospital Ambulatory Medical Care Survey (NHAMCS) with the primary goal to assess the rate and patterns of head CT imaging in ED. Results: There were an estimated 117 million in 2007 and 139 million ED visits in 2017. There was a 4% increase in the any CT use in 2017 compared to 2007. No significant change in head CT utilization rate was seen. The 2007 head CT rate was 6.7% (95% CI: 6.1–7.3) compared to 7.7% (95% CI: 6.8–8.6) in 2017. Trauma, Headache and Dizziness are the top three indications for head CT use in the ED respectively. On adjusted analyses, significantly higher head CT utilization was seen in elderly, (age>65 yrs) and significantly lower utilization rate was seen in Non-Hispanic Black and Medicaid patients, and patients in rural locations. Conclusions: Previously reported exponential growth of CT use in ED is no longer seen. In particular, there was no significant change in ED head CT use between 2007 and 2017. Headache and Dizziness remain commonly used indications despite limited utility in most clinical scenarios, indicating continued need for appropriate use of imaging. There is significantly lower CT utilization in Non-Hispanic Black, Medicaid patients and those in rural locations, suggesting disparities in diagnostic work-up in marginalized and rural populations. This underscores the need for standardizing care regardless of race, insurance status and location.