Effect of azathioprine intolerance on outcomes of inflammatory bowel disease: a cross-sectional study.

Background: Azathioprine is well established for the maintenance of remission in patients with inflammatory bowel disease (IBD). However, a significant proportion of patients are intolerant to azathioprine. It is not clear if intolerance of azathioprine is a marker of poor prognosis for patients who will have a more aggressive disease or be more likely to require surgery.