Background: Idiopathic acute pancreatitis (IAP) in patients with inflammatory bowel disease (IBD) is not well characterized. Our purpose was to better understand this condition and its natural history.
Methods: Retrospective cohort study conducted at nine Spanish IBD referral centers. Patients with IBD and a first episode of acute pancreatitis (AP) between 1998 and 2018 were included. Patients with a previous episode of AP or a diagnosis of chronic pancreatitis were excluded. IAP and non-IAP were compared by multivariate logistic regression and survival analysis.
Results: We identified 185 patients with IBD (68.7% Crohn's disease) and a first episode of AP. Thirty-eight of those 185 (20.6%) fulfilled criteria for IAP. There were no severe cases of IAP. On multivariate analysis, AP before IBD diagnosis (21.1% vs. 3.4%, p = 0.04) and ulcerative colitis (52.6% vs. 23.1%, p = 0.002) were significantly more common in IAP. Further work-up was performed in 16/38 (42%) IAP patients, and a cause was identified in 6/16 (37.5%). Median time from AP to the end of follow-up was 6.3 years (3.1-10). Five-year risk of AP recurrence was significantly higher in IAP group (28% vs. 5.1%, log-rank p = 0.001), with a median time to first recurrence of 4.4 months (2.9-12.2).
Conclusions: IAP represents the second cause of AP in patients with IBD. It is more frequent in ulcerative colitis, and presents a high risk of recurrence. Additional imaging work-up after a first episode of IAP in IBD patients is highly advisable, as it identifies a cause in more than one-third of cases.
Keywords: Crohn disease; Inflammatory bowel diseases; Pancreatitis; Ulcerative colitis.
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