Standard dose versus low dose of azathioprine in the treatment of Crohn's Disease: a prospective randomized study.

Objective Azathioprine (AZA) is widely used in Crohn's disease (CD) patients with a recommended dose, 2-2.5 mg/kg/d, for Westerners. Asian patients are suggested with a lower dose. However, many clinicians reported a poor efficacy with a reduced dose. Our prospective study aims to find a safe dose providing the best efficacy for Chinese CD patients. Methods Fifty active Chinese CD patients were enrolled in our test and randomly split into 2 groups, 25 each. All other treatments were the same except that group A took 1 mg/kg/d and group B took 2 mg/kg/d of AZA. We analysed the complete remission (CR) rate and the response rate on week 12, 24, 48 and with the method of intent-to-treat (ITT) and Per-Protocol (PP) analysis to evaluate the efficacy. Meantime, we evaluated the adverse events and the recurrence rate in both groups. Results On week 48, the CR rate and response rate in group B (ITT: 50.0% and 59.1%; PP: 57.9% and 68.4%) were significantly higher than those in group A (ITT: 13.0% and 17.4%; PP: 16.7% and 22.2%) (P < 0.05). one pancreatitis, one arthritis and two myelosuppression as adverse events happened in group A, while in group B, one arthritis and two myelosuppression happened. The recurrence rate in group A was higher than in group B (P = 0.042). Conclusions 2 mg/kg/d of AZA is more appropriate than 1 mg/kg/d for Chinese CD patients with a high efficacy rate, a low recurrence rate and no ascent in adverse events.