P256 Risk of relapse according to endoscopic score of mucosal healing (mayo score 0 vs. 1): Clinical evaluation is still necessary

Abstract Background Mucosa healing (MH) is a potential therapeutic target in ulcerative colitis (UC) and most clinical trials has used a Mayo endoscopic score (MES) ≤ 1 as an endpoint to define MH . However, a MES of 0 is associated with a lower risk of relapse over time compare to MES 1 but there are few data about clinical and histological features involve in clinical relapse. Methods Aim: evaluate the long-term risk of relapse in UC patients presenting endoscopic MH and relate to clinical and histologic characteristics at time of endoscopy. We performed a retrospective observational study ( cohort study) of consecutives UC patients presenting endoscopic MH (defined by MES 0 and 1) in complete colonoscopy. At time of colonoscopy, clinical disease activity was assessed using the total Mayo score (TMS)(which include MES). Histological disease activity was categorised into 6 groups ( from 0 to 5) based on Geboes scoring system. All patients were followed during 18 months and clinical relapse was defined as need for induction treatment, treatment escalation, hospitalisation and surgery. Cox-regression analysis was performed to identify potential predictive factors to relapse. Results Seventy-four UC patients (31F; mean age 44 ± 15 years ; E1 9.6%, E2 64.8%, E3 25.6%) were included. Endoscopic MH was classified as MES 0 and MES 1 in 61( 82.4%) and 13 (17.6%) .patients, respectively. A Total Mayo score was assessed as 0 in 52 ( 70.3%) patients while 1 ( due to MES) were assigned to 9 (12.2%) patients. Thirteen (17.5%) patients showed a total score ≥2 points ( TMS 2 = 8, TMS 3 = 3, TMS 4 = 1, TMS 5 = 1). Using Geboes categorised score (GCS), classification of 0 (normalised mucosa) was presented in 5 (6.7%) patients, GCS 1 and 2 (quiescent colitis) in 17 (30 %) and 41 (55.5%) patients, respectively. GCS demonstrated active inflammation in 11 (14.8%) patients ( GCS 3 = 6, GCS 4 = 4, GCS 5 = 1). A total of 23 (23/74; 31%) patients presented a relapse during the 18 months follow-up, 17 (17 /61; 27.8%) patients with MES 0 and 6 (6/13; 46%) with MES 1. Clinical evaluation using the total Mayo score was independently associated with UC long-term relapse (hazard ratio, 1.5 ;95% confidence interval, 1.29–1.97; p < 0.001) and a statistically significant correlation between the total Mayo score and the histologic score was found (Spearman correlation = 0.481, p < 0.001). Conclusions The mucosal healing defined only by MES of 0 or 1 is not enough to evaluate the risk of cl