Impact of celiac disease on the clinical course of inflammatory bowel disease: CEL_EII study by GETECCU.

Background: Inflammatory bowel disease (IBD) and celiac disease (CeD) are immune-mediated digestive disorders with shared genetic, immunological, and environmental risk factors. Objectives: This study aimed to assess whether the coexistence of CeD and IBD is associated with a differential IBD disease course. Design: Multicenter case-control study. Methods: This study included patients with both CeD and IBD, and controls with IBD alone in a 1:2 ratio, matched by sex, IBD type, and year of diagnosis. CeD was diagnosed based on a Marsh score >1. Data on IBD phenotype and treatment, mortality and neoplasm development were collected from medical records. Results: The study included 66 celiac-IBD patients (30 ulcerative colitis, 6 indeterminate colitis, 30 Crohn's disease; mean age 30 ± 14 years) and 132 non-celiac-IBD patients (68 ulcerative colitis, 4 indeterminate colitis, 60 Crohn's disease; mean age 32 ± 14 years). Among patients with CeD, Marsh type 3 was the most frequently observed lesion. No significant differences were observed between celiac and non-celiac-IBD patients in terms of IBD extension, extraintestinal manifestations, or coexisting autoimmune diseases. Similarly, no differences were found in outcomes including perianal disease, use of mesalamine, immunomodulators, biologics, need for surgery, or development of neoplasms. No deaths occurred in either group. Conclusion: In this large multicenter cohort, the concurrent diagnosis of CeD and patients with IBD was not associated with a different IBD phenotype or worse outcomes compared to non-celiac-IBD patients. The coexistence of CeD does not appear to alter the natural history of IBD.