Abstract
BACKGROUND AND AIMS: Complete histological normalisation and reduction of inflammation severity in patients with ulcerative colitis are associated with improved clinical outcomes, but the clinical significance of normalisation of only segments of previously affected bowel is not known. We examined the prevalence, pattern, predictors, and clinical outcomes associated with segmental histological normalisation in in patients with ulcerative colitis. METHODS: Medical records of patients with confirmed ulcerative colitis and more than one colonoscopy were sought. Segmental histological normalisation was defined as histological normalisation of a bowel segment [rectum, left-sided or right-sided colon] that had previous evidence of chronic histological injury. We assessed the variables influencing these findings and whether segmental normalisation was associated with improved clinical outcomes. RESULTS: Of 646 patients, 32% had segmental and 10% complete histological normalisaton when compared with their maximal disease extent. Most [88%] had segmental normalisation in a proximal-to-distal direction. Others had distal-to-proximal or patchy normalisation. On multivariate analysis, only current smoking [p = 0.040] and age of diagnosis ≤16 years [p = 0.028] predicted segmental histological normalisation. Of 310 who were in clinical remission at initial colonoscopy, 77 [25%] experienced clinical relapse after median 1.3 [range 0.06-7.52] years. Only complete histological normalisation of the bowel was associated with improved relapse-free survival (hazard ratio [HR] 0.23; 95% confidence interval [CI] 0.08-0.68; p = 0.008]. CONCLUSIONS: Segmental histological normalisation occurs in 32% of patients with ulcerative colitis and is increased in those who smoke or were diagnosed at younger age. Unlike complete histological normalisation, segmental normalisation does not signal improved clinical outcomes.