Rates of Concurrent Computed Tomography Imaging Following Ultrasound for Pediatric Patients With Appendicitis.

Introduction: Imaging guidelines recommend an ultrasound (US)-first approach to evaluate appendicitis to minimize radiation. However, the association between US and computed tomography (CT) utilization remains unclear. We aimed to determine how increased US utilization correlated with the rate of CT evaluation of pediatric acute appendicitis.

Methods: We conducted a retrospective cohort study using the 2019 Nationwide Emergency Department Sample. Eligible patients were aged less than 18 y with a diagnosis of appendicitis. Imaging was determined by Current Procedural Terminology codes. Concurrent imaging was defined as US and CT use during the same encounter. We calculated the hospital rate of concurrent imaging and categorized hospitals into tertiles: low (< 20%), medium (20%-40%), and high (> 40%). We developed generalized ordinal logistic regression models with inverse probability weighting to assess patient characteristics and hospital rates of concurrent imaging associations.

Results: Our analysis included 485 hospitals and 23,976 patients. Thirty four percent were treated at hospitals in the lowest, 35% at the middle, and 31% at the highest tertile hospitals. We observed a negative correlation (-0.27, P < 0.001) between increasing US use and concurrent imaging use. The odds of presenting to a higher concurrent imaging rate hospital were significantly lower for Blacks (adjusted odds ratio [aOR] [95% confidence interval {CI}]: 0.6, [0.4-0.9]) and Hispanics (aOR [95% CI]: 0.7 [0.5-0.9]) in comparison to Whites. The odds of presenting to a higher concurrent imaging rate hospital were higher for patients in the second (aOR [95% CI]: 1.9 [1.2-3.2]) and lowest income quartile (aOR [95% CI]: 3.7 [1.1-13.1]) compared to the highest income quartile.

Conclusions: Increased US use correlated with decreased CT utilization for diagnosing appendicitis. White children and those in lower socioeconomic neighborhoods are more likely to visit hospitals with high concurrent imaging use.