Frequency and predictors for pancreatitis among patients treated with thiopurine: A large database study

Acute pancreatitis is a rare adverse effect of thiopurines. The present study aimed to investigate the frequency, rate, and risk factors for pancreatitis in thiopurine users. This population-based retrospective cohort study. We included all patients treated with thiopurine for any indication between 2000 and 2022. A recorded diagnosis of pancreatitis after the initiation of thiopurine treatment. This population-based retrospective cohort study. A total of 19,348 patients were enrolled in the present study. 15,685 (81.1%) patients were treated with azathioprine, while 3663 (18.9%) were treated with 6-Mercaptopurine. Acute pancreatitis was recorded in 421 (2.2%) of all patients. Patients with pancreatitis were aged 45.5 ± 17.5 vs 45.8 ± 19, p = 0.723), had higher rates of smoking (35.9% vs 22.5%, p < 0.001), had a higher proportion of mercaptopurine use (26.1% vs 18.8%, p < 0.001), had more Crohn's disease (51.8% vs 34.3%, p < 0.001), and had a higher all-cause mortality rate (22.1% vs 16.8%, p = 0.004). Pancreatitis was most common among Crohn's disease patients, with 3.2% of Crohn's disease patients treated with thiopurines compared to other diseases. In a multivariant analysis smoking and Crohn's disease were found to be independent risk factors for pancreatitis (OR 1.904, 95% CI 1.555-2.331, p < 0.001, OR 1.938, 95% CI 1.580-2.376, p < 0.001, respectively). This large, population-based study demonstrates that acute pancreatitis is a relatively rare but significant adverse effect associated with thiopurine use, with a frequency rate of 2.2% of patients. Notably, Crohn's disease and smoking were found to be significant risk factors for developing pancreatitis, which highlights the importance of closely monitoring high-risk patients.