132 Computed Tomography Utilization for Non-Traumatic Abdominal Pain in the Emergency Department Shows Minimal Variability

Abstract

We examined the variability of computed tomography (CT) ordering practices for non-traumatic abdominal pain (NTAP) across physicians in the emergency department (ED) using both patient-visit and physician-level factors. A retrospective study was conducted among 6,502 ED visits for NTAP from January 1 to December 31, 2012 at a large, urban, academic, tertiary care hospital. Visits were selected by chief complaint (excluding trauma unit) and were excluded due to pregnancy, < 18-years-old, incomplete radiology data, physicians with < 45 visits or no physician provider. The relationship of patient-visit and physician-level factors with CT ordering was investigated using univariate and multivariate generalized linear models with repeated measures. A two-level hierarchical logistic regression model with physician-specific random intercepts was used to estimate the inter-physician variation with fixed effects of the patient-visit and physician-level factors. Intraclass correlation coefficient (ICC) based on the standard logistic function variance (π2/3) was calculated. The ED patient visits represented female (67.2%), 23-63 years old (73.6%), walk-ins (77.5%), during weekdays (75.7%), with moderate acuity (70.4%), and were discharged from the ED (72.1%). Overall CT utilization rate across physicians was 27.5%. Forty-five physicians provided care with the median annual visit volume (for the chief complaint of abdominal pain) of 129 (IQR: 97−209), and median CT ordering rate of 27.1% (IQR: 22.9−30.5%). The generalized linear regression analyses showed that after adjusting for the patient-visit factors only, admission team, prior CT test, ED arrivals in previous 4 hours, ultrasound, and white blood cell (WBC) count were statistically significant factors associated with CT ordering; after adjusting for the physician-level characteristics only, years after completing medical school, fellowship, and advanced triage physician were statistically significant factors. The hierarchical logistic regression analyses considering all patient-visit and physician-level factors together with physician-specific random effect showed that the patient-visit factors including age, arrival mode, acuity, admission team, prior CT, ED arrivals in previous 4 hours, ultrasound, and WBC count had statistically significant associations with physician CT ordering, whereas physician-level factors were not statistically significant. There was only 1 out of 45 physicians (2.2%) with an odds ratio not intersecting 1, which indicated the limited variation across physicians to order CT (Figure). After adjusting for patient-visit and physician-level factors, the calculated ICC was 1.68%. We found minimal physician variability in CT ordering practices for NTAP, similar to the findings by other researchers. Patient-visit factors such as age, arrival mode, acuity, admission team, prior CT, ED arrivals in previous 4 hours, ultrasound, and WBC count were found to largely influence CT ordering practices.