Predictors of bowel damage in the long-term progression of Crohn’s disease

BACKGROUND Crohn’s disease(CD)is a chronic inflammatory bowel disorder that progresses to bowel damage(BD)over time.An image-based index,the Lémann index(LI),has been developed to measure cumulative BD.AIM To characterize the long-term progression of BD in CD based on changes in the LI and to determine risk factors for long-term progression.METHODS This was a single-center longitudinal cohort study.Patients who had participated in prospective studies on the accuracy of magnetic resonance imaging using endoscopy as a gold standard and who had a follow-up of at least 5 years were reevaluated after 5-12 years.RESULTS Seventy-two patients were included.LI increased in 38 patients(52.8%),remained unchanged in 9 patients(12.5%),and decreased in 25 patients(34.7%).The small bowel score and surgery subscale significantly increased(P=0.002 and P=0.001,respectively),whereas the fistulizing subscale significantly decreased(P=0.001).Baseline parameters associated with BD progression were ileal location(P=0.026),CD phenotype[stricturing,fistulizing,or both(P=0.007,P=0.006,and P=0.035,respectively)],disease duration>10 years(P=0.019),and baseline LI stricturing score(P=0.049).No correlation was observed between BD progression and baseline clinical activity,biological markers,or severity of endoscopic lesions.CONCLUSION BD,as assessed by the LI,progressed in half of the patients with CD over a period of 5-12 years.The main determinants of BD progression were ileal location,stricturing/fistulizing phenotype,and disease duration.