Moderate‐to‐severe Endoscopic Inflammation is Frequent After Clinical Remission in Pediatric Ulcerative Colitis

ABSTRACT Objectives: Pediatric ulcerative colitis (UC) is characterized by low sustained remission rates and frequent extension of disease even if clinical remission is obtained with therapy. Moderate‐to‐severe endoscopic activity is a risk factor for relapse while prospective evidence regarding early mucosal healing or persistence of inflammation after remission in children is not available. Our aim was to evaluate if significant inflammation is common after clinical remission and could explain the high relapse rate in pediatric UC. Methods: Pediatric UC patients with clinical remission, defined as pediatric UC activity index (PUCAI) scores <10, were prospectively assessed for mucosal healing by endoscopy 3 to 5 months after remission was documented. Mayo score was assessed for each segment by a blinded adult gastroenterologist using central reading. Symptomatic patients before sigmoidoscopy were excluded. Sustained remission was assessed retrospectively at 18 months follow‐up. Results: Forty‐two children were screened, 28 children in continuous clinical remission at time of sigmoidoscopy were included. Mayo 0 was present in 12/28 (42.86%), Mayo 1 in 2/28 (7.1%) and Mayo 2 to 3 in 14/28 (50.0%) endoscopies. Among 23 patients with follow‐up through 18 months, remission was sustained in 6/12 (50.0%) with Mayo score 0 to 1 versus 2/11 (18.18%) of patients with Mayo 2 and 3. Conclusions: Over 50% of children assessed for mucosal healing 3 to 5 months after clinical remission is obtained, have endoscopic disease, primarily moderate‐to‐severe Mayo 2 to 3 inflammation, which was associated with lower sustained remission.