Mo1091 Utility of Abdominal CT Scanning for Non-Traumatic Abdominal Pain in Adults - A Prospective Analysis

Abstract

Background: Abdominal pain is one of the most common reasons for presentation to the hospital and its prevalence as a chief complaint has increased over the last decade. Coincident with these advanced, the use of CT scanning has grown substantially raising questions as to whether the additional cost and risk is acceptable. The aim of this study is to better understand the overall utilization of abdominal CT scans in patients with non-traumatic abdominal pain cared for in our emergency department, and further to determine whether there are specific clinical features that may assist care providers to better triage the use of abdominal CT scanning in this group of patients. Methods: We conducted a prospective cohort study at the Medical University of South Carolina (MUSC), a tertiary care center, in adult patients presenting with non-traumatic abdominal pain as their chief complaint. The study included adult patients presenting to the adult emergency department from October 2013 to January 2014. Variables collected included age, gender, history of present illness, relevant past medical history including previous GI disorders or abdominal surgeries, vital signs, laboratory values, CT results and disposition. Patients that had presented to the ED at any point within the prior two weeks and pregnant women were excluded. Regression analyses were performed to evaluate demographic and clinical variables associated with an abnormal CT result. Results: 1314 patients with abdominal pain were identified over the study period, of which 864 were included; patients were predominantly female (505/864) ranging in age from 18 to 97. 238 underwent CT scans to further evaluate their abdominal pain. The median age was 42 in patients that did not have a CT ordered vs. 48 for those that underwent CT scanning. Although many different lesions were identified, the most common abnormalities found on CT included small bowel obstruction, obstructive nephrolithiasis and appendicitis. Patients with an abnormal CT scan had an elevated white blood cell count (WBC) compared to those with a negative CT scan (11.6 vs. 8.0, p <0.0001). A multivariate logistic regression analysis using multiple clinical variables identified WBC, iron deficiency anemia, diabetes mellitus, a past history of cancer or peptic ulcer disease as predictors of an abnormal CT scan. These variables together yielded a predictive model for an abnormal CT scan with an AUC of 0.80 (95%CI, 0.75-0.86). Conclusions: These findings suggest that emergency room patients with a leukocytosis are more likely to have an abnormal CT scan. Further, patients with iron deficiency anemia or diabetes mellitus or a history of cancer or peptic ulcer disease should also be considered to be more likely to have an abnormal CT, and thus should be carefully evaluated. Our model predicts those with an abnormal CT scan with high accuracy.