Impact of the COVID pandemic on emergency department CT utilization: where do we go from here?

Abstract

Purpose: To analyze the impact of the coronavirus disease (COVID) pandemic on emergency department (ED) computed tomography (CT) utilization.

Methods: A retrospective observational study was conducted assessing seven hospitals' ED imaging volumes between Jan. 6, 2019, and Feb. 27, 2021. Weekly CT utilization is reported as CTs ordered per 100 ED visits. Utilization was ascertained in aggregate and by body area. Interrupted time series analysis was performed to assess significance of utilization change. Prespecified sensitivity analysis was performed for influenza-like or COVID-like illness (ILI/CLI).

Results: Weekly ED CT utilization increased from 35.9 CTs per 100 visits (95% confidence interval [95% CI] 35.8-36.1) to 41.8 per 100 visits (95% CI 41.7-42.0) in pre- and post-pandemic periods. Weekly ED CT chest utilization increased immediately following the pandemic declaration (+ 0.52 chest CTs per 100 ED visits, 95% CI 0.01-1.03, p < 0.05) and compared to pre-pandemic period (+ 0.02 per 100 ED visits, 95% CI 0.02-0.05, p < 0.02). For both CT abdomen/pelvis and CT head, there was neither an immediate effect (+ 0.34 CT-AP per 100 ED visits, 95% CI - 0.74 to 1.44, p = 0.89; - 0.42 CT-H per 100 ED visits, 95% CI - 1.53 to 0.70, p = 0.46) nor a change in weekly CT utilization (+ 0.03 CT-AP per 100 ED visits, 95% CI - 0.01 to 0.05, p = 0.09; + 0.03 CT-H per 100 ED visits, 95% CI - 0.01 to 0.06, p = 0.10). CONCLUSION: These data may help formulate future strategies for resource utilization and imaging operations as we envision a future with COVID and other federal mandates affecting imaging utilization and appropriateness.

Keywords: COVID-19; Clinical operations; Computed tomography; Emergency department; Emergency radiology; Imaging utilization.

Fig. 1

CT utilization and COVID + cases over time. CT utilization, defined as number of CTs ordered per 100 visits, is plotted in blue. The number of COVID + cases per 100 ED visits is plotted on the secondary y axis on the dotted line. Weekly adjusted ED CT utilization increased from 35.9 CTs per 100 visits (35.8–36.1) in pre-pandemic to 41.8 CTs per 100 visits (41.7–42.0) in post-pandemic period

Fig. 2

Interrupted time series analysis of weekly CT chest utilization per 100 ED visits. Weekly ED CT chest utilization adjusted for sex, age, admit rate, and ED length of stay. Prior to the pandemic declaration during the week of 3/8/20 (Week 62), there was no significant change in the weekly ED CT chest utilization. In the first week following the pandemic declaration, there was an immediate significant increase in ED CT chest utilization (+ 0.52 chest CTs per 100 ED visits, 95% CI 0.01–1.03, p < 0.05) and a significant increase in the pandemic weekly rate of ED CT chest utilization compared to the pre-pandemic period (+ 0.02 chest CTs per 100 ED visits, 95% CI 0.02–0.05, p < 0.02). Mean weekly ED CT chest utilization reached a bimodal peak during the post-pandemic period of 7.05 and 8.56 CTs per 100 ED visits during the weeks of 4/19/20 and 11/15/20, respectively

Fig. 3

Interrupted time series analysis of weekly CT chest utilization per 100 ED visits among ED visits suspected to have influenza-like or COVID-like illness. In the first week following the pandemic declaration (week 62), there was an immediate significant increase in ED CT chest utilization (+ 0.77 chest CTs per 100 ED visits, 95% CI 0.14–1.40, p-0.02), and in the following weeks, there was a significant increase in the pandemic weekly rate of ED CT chest utilization compared to the pre-pandemic period (+ 0.04 chest CTs per 100 ED visits, 95% CI 0.02–0.06, p < 0.0001). Although weekly CT chest utilization in this sensitivity analysis cohort reached bimodal peaks coinciding with the trends observed in the main analysis (Fig. 3; 5.45 and 7.64 CTs per 100 ED visits during the weeks of 4/19/20 and 11/15/20, respectively), CT utilization notably decreased in the weeks between these bimodal peaks to a level below that of the pre-pandemic rate (nadir 2.68 CTs per 100 ED visits on 8/30/20)