Capsule Endoscopy: Diagnostic Accuracy of Lewis Score in Patients with Suspected Crohn's Disease.

Background: The Lewis Score (LS) aims to standardize the method of quantification of small bowel inflammatory activity detected by the small bowel capsule endoscopy (SBCE). The aim of this study was to evaluate the diagnostic accuracy of the LS in patients with suspected CD undergoing SBCE.

Methods: We performed a retrospective study including patients who underwent SBCE for suspected CD between September 2006 and February 2013. Patients were grouped according to the criteria of the International Conference on Capsule Endoscopy for the definition of suspected CD. Inflammatory activity on SBCE was objectively assessed by determining the LS.

Results: Ninety-five patients were included. Group 1: 37 patients not fulfilling International Conference on Capsule Endoscopy criteria; Group 2: 58 patients with ≥ 2 International Conference on Capsule Endoscopy criteria. The diagnosis of CD was established in 38 patients (40%): 8 (21.6%) from group 1 and 30 from group 2 (51.7%) (P = 0.003). Among those patients, 34 had LS ≥ 135 (73.9%) and 4 had LS <135 (8.2%) at SBCE (P < 0.001). The LS ≥ 135 had an overall diagnostic accuracy of 83.2% with a sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of CD of 89.5%, 78.9%, 73.9%, and 91.8%, respectively.

Conclusions: The application of LS ≥ 135 as the cutoff value for the presence of significant inflammatory activity in patients undergoing SBCE for suspected CD may be useful to establish the diagnosis of CD. In patients with LS < 135, the probability of having CD confirmed on follow-up is low.