Background Autoimmune pancreatitis (AIP) is an uncommon inflammatory disorder that may accompany inflammatory bowel disease (IBD). The clinical relevance of AIP-IBD coexistence, therapeutic strategies, and long-term outcomes are scarcely known. Methods In this ECCO COllaborative Network For Exceptionally Rare case reports project (ECCO-CONFER) we included cases of AIP diagnosed in patients with IBD. Data on the diagnostic criteria, clinical characteristics, and patient outcomes were retrospectively collected and analysed. Results The cohort included 82 patients [54% males, 77% with ulcerative colitis (UC), age at IBD and AIP diagnosis 32±16 and 35±16 years, respectively]. Of all AIP patients, 71% were classified as type 2, 21% as type 1, and 8% as undefined type. Detailed characteristics of the study group are shown in Table 1. In 57% of the individuals, IBD was diagnosed before AIP. In the remaining cases, IBD was diagnosed simultaneously (20%) or afterwards (23%). Half of the patients required immunomodulators and 43% biological therapy to control their IBD. Twenty-two percent of UC and 6% of Crohn’s disease (CD) required surgical intervention during a mean follow-up of 3.6±3.4 years. Histological confirmation was used in 38% of cases, while the remaining were diagnosed as probable AIP based on clinical, biochemical, and radiologic criteria. Magnetic resonance was the most frequently used imaging modality (61%). Eighty percent of patients received steroids for AIP. Thiopurines were used for AIP in 16 (19%) patients, 81% of them responded to treatment. One patient was successfully treated for AIP with infliximab. AIP complications occurred in 27%, including pancreatic exocrine insufficiency (19%) and diabetes (13%). Five patients underwent surgery due to suspected pancreatic cancer. Patients with complicated AIP were significantly older at AIP and IBD diagnosis, were more frequently males and presented with weight loss at AIP diagnosis, and had less frequently a family history of IBD (Table 1). Colonic IBD (i.e. UC, isolated colonic IBD-unclassified or colonic CD) was seen in a higher proportion of individuals with complicated vs benign AIP course (91% vs 33%, p<0.0001). At the end of follow-up, 75 (91%) and 73 (89%) patients were in remission of AIP and IBD, respectively. No IBD or AIP-related deaths were reported. Conclusion 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. Older age, male gender, isolated colonic IBD location, and weight loss at AIP presentation were seen in higher proportions of patients with a complicated course of AIP.

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.