Epidemiology of fibrostenosing inflammatory bowel disease.

Fibrostenosis occurs in both Crohn's disease (CD) and ulcerative colitis (UC). Up to 21% of patients with CD present with strictures at diagnosis, while the rate of stenosis varies from 1% to 11% in UC. Despite the increasing use of immunomodulators and biologics in treatment, there has been no decrease in the rate of progression from inflammatory to complicated disease phenotypes (either stricturing or penetrating). The presence of stenosis is an independent risk factor for surgery in patients with CD, who are at a risk of postoperative recurrence at a rate of up to 55% at 10 years after surgery. Patients with inflammatory bowel disease (IBD) strictures are at risk of malignant transformation. Thus, surveillance colonoscopy should be offered to this group of patients. Several risk factors for the development of stricture have been identified. In CD, patients aged less than 40-years old, with perianal disease at diagnosis, who need steroids at the first flare up or have ileal disease are at the risk of developing strictures; while in UC, patients with extensive colitis and long-standing disease are at risk. Recently, microbiota signatures have also been identified as markers for stricture development. The presence of Ruminococcus spp. is associated with the development of stricture in pediatric patients with CD. In this review, we highlight the epidemiology, risk factors and natural history of fibrostenosing IBD.