Systematic review: severe endoscopic lesions in inflammatory bowel disease

Background Endoscopy and biopsy are the standard tools for the diagnosis of inflammatory bowel disease (IBD) and the assessment of treatment response. Severe endoscopic lesions (SEL) are commonly observed in IBD, but have been poorly described in the literature. The aim of this review is to provide an overview of the current understanding and gaps in knowledge about these lesions.Methods We performed a systematic review of studies of SEL in patients with IBD. A search was performed in MEDLINE, Embase, and Cochrane CENTRAL databases in July 2024. Studies were eligible if they investigated SEL, its involvement in the disease, its evolution with treatment, and its prognostic implications.Results We found 1172 articles in the Pubmed database and 46 were included. Of the various definitions of SEL used in the literature, most of them are based on the most severe endoscopic items from existing endoscopic scores, but none have been validated. Despite the paucity of literature, the prevalence of SEL is estimated to be 33%-75% in acute severe ulcerative colitis (ASUC) and 22.5%-87% in Crohn's disease (CD). In terms of prognosis, SEL are associated with steroid refractoriness in ASUC and do not affect response to infliximab or ciclosporin. In CD, the response to biologics, especially anti-TNF, is not affected by the presence of SEL.Conclusions There is currently no validated definition of SEL in IBD. When present, they are associated with steroid failure in the setting of ASUC, but do not affect response to anti-TNF in either CD or ASUC.