Increasing Use, Geographic Variation, and Disparities in Emergency Department CT for Suspected Urolithiasis

Purpose: The aim of this study was to examine changing characteristics of utilization and potential disparities in US emergency department (ED) patients undergoing CT of the abdomen and pelvis (CTAP) for suspected urolithiasis. Methods: A retrospective study was conducted among all patients from 2006 to 2015 with a primary diagnosis of suspected urolithiasis within the Nationwide Emergency Department Sample, the largest publicly available all-payer ED database in the United States. The annual numbers of ED visits for suspected urolithiasis and associated CTAP examinations per visit were determined. The compound annual growth rate for CTAP was calculated. Using multivariate logistic regression analyses, patient demographics and payer and hospital characteristics were evaluated as potential independent predictors of utilization. Results: Nationwide, the number of ED visits per year for suspected urolithiasis increased from 1,057,119 in 2006 to 1,246,041 in 2014 (relative +17.9%), whereas the annual use of CTAP increased from 24.6% to 49.4% per visit (relative +100.8%; CAGR +8.0%). Multivariate analysis showed higher CTAP use associated with higher patient household income ZIP code quartile (odds ratio [OR] for wealthiest/poorest, 1.48), private payer (ORs, 1.21 versus Medicare and 1.22 versus Medicaid), Northeast geographic region (ORs, 5.07 versus Midwest, 4.16 versus West, and 1.77 versus South), hospital urban status (OR, 1.42), and nonteaching hospitals (OR, 1.20) (P < .05 for all). Conclusions: The relative use of CTAP in ED patients-presenting with-suspected urolithiasis doubled between 2006 and 2014 and showed marked geographic variation. Among ED patients with suspected urolithiasis, CTAP was more frequent in patients from higher household income ZIP codes, with private insurance, in the Northeast, and at urban and nonteaching hospitals.