Acute pancreatitis in inflammatory bowel disease, with special reference to azathioprine-induced pancreatitis

Abstract

Background: Pancreatitis is a potentially severe condition. Patients with inflammatory bowel disease (IBD) seem to be at increased risk for acute pancreatitis.

Aim: To describe the incidence, main causes and possible predictive factors of acute pancreatitis in inflammatory bowel disease.

Methods: Information was retrospectively extracted from the clinical records of patients followed in the IBD Units of nine hospitals in Madrid (n = 5073).

Results: A total of 82 acute pancreatitis episodes were diagnosed (cumulative incidence, 1.6%); 98% of them were mild. Recurrent acute pancreatitis developed in 13% of patients. Most cases of acute pancreatitis (63.4%) were attributed to drug exposure [azathioprine/mercaptopurine (AZA/MP) n = 46, mesalazine (mesalamine) n = 6]; 20.7% were idiopathic, and 12.2% were biliary. Incidence of acute pancreatitis in patients treated with AZA/MP was 3.1%. In patients with acute pancreatitis, female gender (OR 3.4 95% CI: 1.3-9.3; P = 0.012) and Crohn's disease (CD) (OR 5.8 95% CI: 1.6-20.6; P = 0.007) were risk factors for AZA/MP-associated acute pancreatitis, the latter also when analysed only in patients treated with AZA/MP (n = 1477) (OR 5.2 95% CI: 1.8-14; P = 0.002).

Conclusions: The incidence of acute pancreatitis in our IBD patients (1.6%) is similar to that previously described. Drugs, mainly AZA/MP, are the leading cause. AZA-induced acute pancreatitis is always mild. Patients with CD are at a higher risk for AZA/MP-associated acute pancreatitis. The frequency of idiopathic acute pancreatitis is higher than expected, suggesting that part of these cases could be extraintestinal manifestations of IBD.