Risk Stratification of Emergency Department Patients With Crohn's Disease Could Reduce Computed Tomography Use by Nearly Half

Abstract

Background/Aims Computed Tomography (CT) is a useful tool in Crohn’s disease (CD) to assess disease activity and exclude complications. Excessive radiation has been associated with increased risk of malignancy. We aimed to identify automatable algorithms with a high negative predictive value (NPV) of a significant CT finding in patients with CD presenting to the emergency department. Methods We conducted a retrospective review of a tertiary center’s medical records to identify adults with a diagnosis of CD who presented from 2000–2011. Logistic regression was used to model (1) complications [perforation, abscess or other serious finding] and (2) inflammation. Results There were 1095 visits for 613 individuals with a CT scan within 24 hours of arrival. The average number of CTs was 1.8 with a range of 1–31. Complications occurred in 16.8% of CTs. Inflammation was found in 54.5% of CTs while any new/worse finding was found in 67.2%. Using 10-fold cross validation to evaluate our models, the area under the receiver operating characteristic curve for the complications model is 0.80 (95%CI: 0.74–0.86) and the inflammation model is 0.71 (95%CI: 0.68–0.74). Scanning only patients with model-predicted complications would reduce scans by 43.0%, with a miss rate of 0.8% (4/491). Conclusions Patients presenting to the emergency department with CD undergo CT scanning frequently but have no significant findings in 32.8% and complications in only 17%. Models with high NPVs were identified and could aid physicians in the decision to avoid CT scans in patients with low likelihood of a positive scan. Studies are needed to validate these models beyond a single center.

Utility of Emergency Department Use of Abdominal Pelvic Computed Tomography in the Management of Crohn’s Disease

“…1,2,13,20 However, we found that almost 50% of patients had a clinically significant CT finding. This higher incidence is likely due to a more inclusive definition of what constitutes a CD-related CT finding (abscess, fistula, stricture, perforation, bowel obstruction), in addition to including non-CD related findings (i.e.…”

“…1–4 The estimated use of CT scans in the ED to assess patients with CD ranged from 26–47% in 2001 to 42–78% in the late 2000s. 1,2 While CT scans can be essential in the diagnosis of enteric fistulas, abscesses, or perforations, and are as accurate as other imaging modalities, there is a risk of overutilization. 5–13 Patients presenting to the ED with abdominal pain are undergoing twice as many CT scans in comparison to a decade ago, yet the number of clinically significant findings and admissions have not significantly changed.…”

“…5–13 Patients presenting to the ED with abdominal pain are undergoing twice as many CT scans in comparison to a decade ago, yet the number of clinically significant findings and admissions have not significantly changed. 1,2,4,14 Although the risk of a single CT scan is minimal, repetitive exams on young patients can expose them to harmful amounts of radiation, increase their risk of cancer and nephrotoxicity, as well as escalate medical costs. 14,15 Patients with CD are at a particular risk of overutilization of CT scans as the number of ED visits by these patients has been increasing.…”

“…One model uses history of obstruction, history of abscess, presence of hematochezia, and WBC >12,000 to predict significant findings, whereas the other model uses erythrocyte sedimentation rate (ESR) and CRP. 2,13 Only one of the two models accounts for with-in subject correlated data resulting from subjects with multiple CT scans in the study period, and neither assessed whether results from a prior CT could inform the decision to order a repeat scan. Furthermore, evaluating the predictive ability of previous CT scan findings has yet to be evaluated in the literature.…”

Diagnostic imaging and radiation exposure in inflammatory bowel disease

“…Excessive use of CT imaging in IBD patients presenting to the emergency department (ED) has also raised concern. In a study from the United States, no significant findings were observed in 32.8% of CT imaging studies carried out in IBD patients in the ED [31] . Preliminary algorithms to avoid inappropriate use of CT imaging in IBD patients presenting to the ED have been proposed and require validation [31,32] .…”