Autoimmune pancreatitis in patients with inflammatory bowel disease - a real-world multicentre collaborative ECCO CONFER study.

BACKGROUND: Autoimmune pancreatitis (AIP) is rarely associated with inflammatory bowel disease (IBD). Long-term outcomes of AIP and IBD in patients with AIP-IBD coexistence and predictors of complicated AIP course are scarcely known.

METHODS: An ECCO COllaborative Network For Exceptionally Rare case reports project (ECCO-CONFER) collected cases of AIP diagnosed in patients with IBD. Complicated AIP was defined as a composite of endocrine and/or exocrine pancreatic insufficiency, and/or pancreatic cancer. We explored factors associated with complicated AIP in IBD.

RESULTS: We included 96 patients (53% males, 79% ulcerative colitis, 72% type 2 AIP, age at AIP diagnosis 35±16 years). The majority of Crohn's disease (CD) cases (78%) had colonic/ileocolonic involvement. In 59%, IBD preceded AIP diagnosis, whereas 18% were diagnosed simultaneously. Advanced therapy to control IBD was used in 61% and 17% underwent IBD-related surgery. 82% of patients were treated with steroids for AIP, the majority of which (91%) responded to a single course of treatment. During a mean follow-up of 7 years, AIP complications occurred in 25/96 (26%) individuals. In a multivariate model, younger age at AIP diagnosis (OR=1.05, P=0.008), family history of IBD (OR=0.1, P=0.03) and CD diagnosis (OR=0.2, P=0.04) were associated with uncomplicated AIP course. No IBD or AIP-related deaths occurred.

CONCLUSIONS: In this large international cohort of patients with concomitant AIP-IBD, most patients have type 2 AIP and colonic IBD. AIP course is relatively benign and long-term outcomes are favourable, however, one-quarter develop pancreatic complications. Age, familial history of IBD and CD may predict uncomplicated AIP course.