Switching to a Second Thiopurine in Adult and Elderly Patients With Inflammatory Bowel Disease: A Nationwide Study From the ENEIDA Registry

Abstract Background and Aims Although commonly used in inflammatory bowel disease [IBD], thiopurines frequently cause intolerance, and switching to a second thiopurine has only been reported in some small series. Ours aims in this study were to evaluate the safety of switching to a second thiopurine in a large cohort, and to assess the impact of age on tolerance. Methods Adult IBD patients from the ENEIDA registry, who were switched to a second thiopurine due to adverse events [excluding malignancies and infections], were identified. At the beginning of thiopurine treatment, patients were divided by age into two groups: 18–50 and over 60 years of age. The rate and concordance of adverse events between the first and second thiopurines, treatment intolerance, and persistence with the second thiopurine were evaluated. Results A total of 1278 patients [13% over 60 years of age] were switched to a second thiopurine. At 12 months, the cumulative probability of switch intolerance was 43%, and persistence with treatment was 49%. Independent risk factors of switch intolerance were age over 60 years (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.07–2.07; p = 0.017) , previous gastrointestinal toxicity [OR 1.4; 95% CI 1.11–1.78; p = 0.005], previous acute pancreatitis [OR 6.78; 95% CI 2.55–18.05; p <0.001], and exposure to the first thiopurine <6 months [OR 1.59; 95% CI 1.14–2.23; p = 0.007]. Conclusions In a large series in clinical practice, switching to a second thiopurine proved to be a valid strategy. Tight monitoring of elderly IBD patients switching to a second thiopurine because of adverse events is recommended.