Clinical characteristics of acute pancreatitis in patients with inflammatory bowel disease: a nationwide survey in Japan.

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at increased risk of acute pancreatitis (AP). However, the clinical characteristics of AP in IBD and the differences between ulcerative colitis (UC) and Crohn's disease (CD) remain unclear.

METHODS

We conducted a nationwide, multicenter, retrospective study at 28 institutions in Japan. Patients ≥ 16 years with UC or CD treated between 2012 and 2021 were included. We assessed the characteristics of AP in IBD, including differences between UC and CD. We also compared UC and CD patients with and without AP.

RESULTS

Among 24,849 patients with IBD (16,233 UC and 8,616 CD), 342 (1.4%) developed AP. Among these AP cases, severe AP and mortality were observed in 7.6% and 0.6%, respectively. Drug-induced AP was the most common etiology (55.6%), and autoimmune pancreatitis (AIP) ranked third (10.8%). Compared with UC, CD patients with AP had higher rates of intensive care unit admission (P = 0.002) and severe AP (P = 0.003). CD (odds ratio, 2.96; P = 0.02) and drug-induced or AIP etiology (odds ratio, 0.19; P < 0.001) were associated with severe AP. UC patients with AP had higher rates of pancolitis (P < 0.001), extraintestinal manifestations (P = 0.001), and steroid dependence (P = 0.006) than those without AP.

CONCLUSIONS

AP in IBD showed distinct clinical characteristics compared with AP in the general population. CD patients may develop more severe AP than UC, whereas UC patients with AP may have more aggressive and/or refractory disease features compared with those without AP.