Chronic inflammation and other changes are significant components of clinically fibrotic strictures in Crohn's disease: a histological study of resected strictures clinically characterized as noninflamed.

BACKGROUND: Strictures related to Crohn's disease due to fibrosis are a result of an exaggerated tissue remodelling response to inflammation, characterized by accumulation of collagen-rich extracellular matrix produced by mesenchymal cells. OBJECTIVES: The objective of this study was to characterize histological changes seen in resected 'fibrotic' strictures to better understand individual components of intestinal stenosis. METHODS: We identified patients undergoing surgery for ileal Crohn's disease secondary to symptomatic stricturing disease (Montreal B2) using the histopathology database at Queen Elizabeth Hospital in Birmingham, UK, between 2012 and 2017. Phenotypic data were recorded and resection specimens reviewed. Two independent pathologists applied the semiquantitative scoring system previously developed by us to the microscopic images. Data were analyzed using the possible maximum total score (%PMTS). RESULTS: Forty-eight patients (M = 25) were included. with median disease duration of 7 years (range 0.25-39 years); nearly two-thirds had ileocolonic distribution (L3). In this cohort, despite presurgery diagnosis of noninflamed fibrosis, chronic inflammation was noted to be a prominent component of all strictures. The histological scoring showed presence of several other prominent findings such as muscular hyperplasia and volume expansion.There was statistically significant positive correlation between chronic inflammation and fibrosis and muscular hyperplasia. CONCLUSION: The histological features of Crohn's disease-related strictures show multiple changes in multiple layers and not simply fibrosis. In our cohort, despite the observation prior to surgery that strictures were clinically considered fibrotic, the finding of chronic inflammation as a dominant component at a histological level in the resection is important. The findings might suggest that one of the main drivers of progressive fibrosis is the inflammatory component, which probably is never fully resolved.

Clinical outcomes, predictors of prognosis and health economics consequences in IBD patients after discontinuation of the first biological therapy.

BACKGROUND: In real-world clinical practice, biologics in inflammatory bowel diseases (IBD) may be discontinued for a variety of reasons, including discontinuation initiated by gastroenterologists. The aims of the study are to report outcomes after discontinuation and predictors of prognosis after a minimum follow-up of 24 months; outcomes of gastroenterologist-initiated discontinuation with resulting direct cost implications on the health system were also studied. METHODS: IBD patients who discontinued their first-use biologics between January 2013 and December 2016 were identified at our tertiary centre. Reasons for discontinuation and pre-defined adverse outcomes (AO) were recorded. Data were analysed using univariable and multivariable logistic regressions within a machine learning technique to predict AO. Gastroenterologist-initiated discontinuations were analysed separately, and Kaplan-Meier survival analysis performed; direct costs of AO due to discontinuation were assessed. RESULTS: A total of 147 patients discontinued biologics (M = 74; median age 39 years; Crohn's Disease = 110) with median follow-up of 40 months (range 24-60 months). In the total cohort, there were fewer AO among gastroenterologist-initiated discontinuations compared with patient-initiated; 54% (of the total group) had AO within 6 months. Among 59 gastroenterologist-initiated discontinuations, 23 (40%) had IBD-related AO within 6 months and 53 (90%) patients had AO by end of follow-up. Some 44 (75%) patients needed to restart biologics during follow-up, and direct costs due to AO and restart of biologics were high. CONCLUSIONS: The proportion of patients who have AO following discontinuation of biologics is high; clinicians need to carefully consider predictors of poor prognosis and high relapse rates when discussing discontinuation. The direct costs of managing AO probably offset theoretical economic gains, especially in the era where cost of biologics is reducing. Biologics should probably be continued without interruptions in most patients who have achieved remission for the duration these remain effective and safe.