Predicting the need for azathioprine at first presentation in children with inflammatory bowel disease

Objective: Although azathioprine usually is reserved for inflammatory bowel disease that proves difficult to control, routine early use has recently been advocated for children with Crohn disease. However, this practice carries with it an increased risk of adverse reactions. The objective of this study was to look for characteristics at first presentation that may identify those likely to benefit from early azathioprine. Patients and Methods: Study setting was a tertiary pediatric gastroenterology department. Retrospective cohort study of 156 children (93 Crohn disease, 47 ulcerative colitis, 16 indeterminate colitis), comparing characteristics at presentation in those who did and did not eventually require azathioprine. Azathioprine was reserved for patients with frequent relapses and steroid dependence/resistance. Twenty variables were examined, including patient and disease characteristics and initial treatment response. These were analysed using Kaplan-Meier survival curves, log-rank tests, and Cox proportional hazard regression. Results: Median follow-up was 3.9 years (range 0.5-10.6 years). Azathioprine was used in 36% with Crohn disease and 40% with ulcerative colitis. Median time to commencing azathioprine was 14 months (range 3-77.5 months). Multifactorial analysis revealed an association with endoscopic colitis severity in Crohn disease (P < 0.02). However, only 50% with severe Crohn colitis actually needed azathioprine. There was an association with need for intravenous corticosteroids for induction of remission in Crohn disease (P < 0.006) and ulcerative colitis (P < 0.05). Of these patients, 75% required azathioprine. Conclusions: These findings support the early use of azathioprine in children who require intravenous corticosteroids to induce initial remission. No other characteristics examined were of clinical utility in predicting need for azathioprine.