Establishment of a novel scoring system for colon capsule endoscopy to assess the severity of ulcerative colitis-capsule scoring of ulcerative colitis

Background: The usefulness of second-generation colon capsule endoscopy (CCE-2) for ulcerative colitis (UC) has not been fully demonstrated. This study aimed to develop an endoscopic severity score of UC for CCE-2. Methods: Patients diagnosed with UC were enrolled prospectively and underwent colonoscopy and CCE-2 on the same day. The collected CCE-2 videos were adopted for the development of the score. These videos were scored by 4 blinded inflammatory bowel disease experts. The items validated with the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) were used as the candidate items, some of which were automatically assessed using the workstation. Each item was divided into proximal and distal parts at the splenic flexure and then individually assessed. The image readers simultaneously evaluated the inflammation severity using the visual analog scale (VAS). The descriptors that contribute to this scale were evaluated, and a model to predict the VAS was constructed. The UCEIS was scored by other endoscopists using colonoscopy videos. The correlation coefficients with fecal calprotectin, blood tests, and Lichtiger index were calculated. Results: The final scoring system was fixed as "vascular pattern sum (proximal + distal) + bleeding sum + erosions and ulcers sum (minimum- maximum, 0-14)" and was named Capsule Scoring of Ulcerative Colitis (CSUC). The correlation coefficient of CSUC with biomarkers and clinical score was similar to that of the UCEIS. Conclusions: We developed a new simple score using the 3 descriptors of CCE-2.