Severe adverse events associated with thiopurine therapy in inflammatory bowel disease: A retrospective cohort study from a tertiary centerInflammatory Bowel Disease: A Retrospective Cohort Study from a Tertiary Center.

BACKGROUND AND AIM OF THE STUDY: Thiopurines are cornerstone immunosuppressants for maintenance therapy in inflammatory bowel disease, but their use is limited by potentially serious adverse events. The aim of this study is to characterize severe adverse events associated with thiopurine therapy in a cohort of inflammatory bowel disease patients treated at a tertiary care center.

METHODS

A retrospective observational study was conducted including adult inflammatory bowel disease patients who developed clinically significant adverse events while on thiopurine therapy. Demographic, disease-related, treatment, and outcome variables were collected. Quantitative variables were expressed as means and standard deviations; categorical variables as percentages with 95% confidence intervals. Statistical significance was defined as p < 0.05.

MAIN

RESULTS

Among 722 inflammatory bowel disease patients treated with thiopurines, 81 (11.2%) experienced at least one severe adverse event. Of these, 24 (30%) required hospitalization, and 2 deaths (2.5%) were attributed to thiopurine-associated malignancies. The most frequent adverse events were acute pancreatitis in 31 patients (38.3%), myelotoxicity in 19 (23.4%), malignancies in 13 (16.0%), and hepatotoxicity in 6 (7.4%). Infections and fever of unknown origin were less common, with 3 cases each (3.7%). No statistically significant associations were observed between adverse events occurrence and sex (p = 0.36), IBD subtype (p = 0.21), or thiopurine type (azathioprine vs. 6-mercaptopurine; p = 0.09).

CONCLUSIONS

Thiopurine therapy in inflammatory bowel disease is associated with a notable incidence of severe adverse events, particularly acute pancreatitis and myelotoxicity. No consistent demographic or clinical predictors of toxicity were identified, highlighting the importance of universal monitoring strategies during thiopurine treatment.