P239 Ulcerative Colitis Index of Severity is a better predictor of histologic activity than Mayo endoscopic subscore, an Asian cohort study in ulcerative colitis.
Tay, S.(1);Teh, K.K.J.(1);Wang, L.M.(2);Tan, M.(1);
(1)Singapore General Hospital, Gastroenterology and Hepatology, Singapore, Singapore;(2)Changi General Hospital, Pathology, Singapore, Singapore;
Targets of therapy in ulcerative colitis (UC) have undergone a shift from clinical remission to endoscopic healing (EH). Recent STRIDE II guidelines1 have recommended stricter criteria for EH, Ulcerative Colitis Index of Severity (UCEIS) ≤1 or Mayo endoscopic subscore (MES)=0, with histologic healing (HH) as an adjunctive endpoint. We aim to ascertain the strength of correlations between EH and HH using validated indices in an Asian cohort.
A single-centre cohort study was performed in a tertiary centre. Patients with a diagnosis of UC were prospectively enrolled into a database from January 2017 to June 2020. Patient demographics, clinical classification, endoscopic and histological assessments were collected retrospectively and analysed. Endoscopic scores in the worst affected segments by two independent gastroenterologists. Histological activity was assessment by a single gastrointestinal histopathologist using the Nancy Histological Index (NHI). Analysis was done using SPSS v23. Spearman correlations between UCEIS, MES and NHI was performed.
A total of 88 patients with UC were enrolled (Figure 1). Seven patients were excluded as no biopsies were done during endoscopy. Analysis was done for 163 pairs of endoscopy and histology. The distribution of UCEIS, MES and NHI scores for all endoscopies are shown in Figure 2. Both MES and UCEIS had modest correlations with NHI but UCEIS had a stronger correlation to NHI (r=0.640, p<0.01) than MES (r=0.538, p<0.01) (Figure 3). When evaluating patients in EH (UCEIS≤1 or MES=0), both endoscopic scores had similar distribution of NHI scores (Figure 4a & 4b). Despite appearing to be endoscopically inactive, more than half of patients had histologically active disease, with NHI≥2 (14/27 [51.8%] in the UCEIS≤1 group, 9/17 [52.9%] in the MES=0 group). When using the older definition of EH (MES≤1), 49 of 66 patients (74%) had histologically active disease with NHI≥2 (Figure 4c).
UCEIS ≤1 is slightly more predictive of HH than MES=0 but endoscopic correlation with HH is poor. Biopsies should still be performed if HH is a desired treatment outcome. The more stringent criteria change for EH in STRIDE II from MES≤1 to MES=0 results in higher rates of HH.
1Turner D, et al.; International Organization for the Study of IBD. STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD. Gastroenterology. 2021 Apr;160(5):1570-1583.