P0213A retrospective comparison of endoscopic ultrasonography and clinical parameters in assessing Ulcerative Colitis activity

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD). The main goal of treatment is to induce and maintain remission. Therefore, determining disease activity plays a crucial role in treatment decisions. (1) EUS has been studied in the assessment of UC activity. A scoring system was developed by Tsuga et al., and later Yan et al. proposed a revised EUS-UC score to improve interrater reliability. (2,3) Despite previous studies, the necessity of EUS in assessing UC activity remains uncertain. In this study, we aimed to evaluate the efficacy of EUS in assessing UC activity, compare EUS findings with clinical, biochemical, endoscopic, and histological parameters, and investigate whether EUS is superior to the endoscopic Mayo score and the Mayo score in predicting histological activity. Methods The data of 39 patients aged 18 and older, diagnosed with UC, who underwent rectal radial EUS at Dokuz Eylül University Faculty of Medicine Hospital, Gastroenterology Clinic between 01.01.2024 and 01.10.2024, were retrospectively analyzed. Anamnesis information, Mayo score, Truelove-Witts classification, endoscopic Mayo score, laboratory values, and EUS findings were obtained from the hospital information system. Preparations retrieved from the pathology archive were reevaluated, and Geboes histological score(GHS), Nancy histological index (NHI), and Robart histopathology index (RHI) were calculated. EUS findings were compared with other parameters. Results A significant positive correlation was found between revised EUS UC score and Mayo score (r = 0,723; p 0,001), endoscopic Mayo score (r = 0,710; p 0,001), GHS (r = 0,506; p 0,001), NHI (r = 0,576; p 0,001), and RHI (r = 0,553; p 0,001). Rectal wall thickness also correlated with fecal calprotectin (r = 0,348; p = 0,035). When revised EUS UC score analyzed in Mayo score subgroups, the difference between remission and mild activation groups (p = 0,007), and difference between remission and medium/severe activation groups (p = 0,001) were statistically significant. ROC analysis showed that, according to GHS/NHI, the AUC for the revised EUS UC score was 0,872 (95% CI: 0,750-0, 995; p = 0,001), while the AUC for the Mayo score was 0,959 (95% CI: 0,903-1, 000; p 0,001). The DeLong test indicated no significant difference between the AUCs (p = 0,1646). Conclusion EUS was found to be effective in assessing UC activity but its superiority over the Mayo score in predicting histological activity could not be demonstrated. To investigate the superiority of EUS over traditional methods, larger sample-sized, prospectively designed cohort studies are needed, in which inter-observer reliability is assessed, patients are followed up after treatment, and long-term outcomes are evaluated. References: 1) Chavannes M, Dolinger MT, Cohen-Mekelburg S, Abraham B. AGA clinical practice update on the role of intestinal ultrasound in inflammatory bowel disease: commentary. Clin Gastroenterol Hepatol. 2024;22(9):1790-1795.e1. 2) Tsuga K, Haruma K, Fujimura J, et al. Evaluation of the colorectal wall in normal subjects and patients with ulcerative colitis using an ultrasonic catheter probe. Gastrointest Endosc. 1998;48(5):477-484. 3) Yan B, Feagan B, Teriaky A, et al. Reliability of EUS indices to detect inflammation in ulcerative colitis. Gastrointest Endosc. 2017;86(6):1079-1087. Conflict of interest: Dr. Yalçın, Eren: No conflict of interest Bengi, Goksel: No conflict of interest Dolu, Süleyman: No conflict of interest Büyüktorun, Ilker: There is no conflict of interest Mehtiyev, Rauf: No conflict of interest Pehlivanoglu, Burcin: No conflict of interest Keskinoğlu, Pembe: No conflict of interest Soytürk, Müjde: No conflict of interest