Comparative effectiveness of azathioprine in Crohn's disease and ulcerative colitis: prospective, long-term, follow-up study of 394 patients

Aliment Pharmacol Ther. 2008 Jul;28(2):228-38. doi: 10.1111/j.1365-2036.2008.03732.x. Epub 2008 May 12.


Background: The long-term efficiacy for thiopurinic drugs in Crohn's disease (CD), and particularly in ulcerative colitis (UC), has been insufficiently studied.

Aim: To evaluate prospectively and compare the long-term effectiveness of azathioprine (AZA) in CD and UC.

Methods: Three hundred and ninety-four AZA treated patients were included consecutively included. Truelove-modified index and CDAI were used to assess effectiveness. Hospitalizations and surgical procedures were recorded.

Results: Two hundred and thirty-eight patients with CD and 156 with UC received AZA for a median of 38 months.

Effectiveness: Partial response/remission was achieved in 34%/49% of CD patients and in 47%/42% of UC (nonstatistically significant differences). STEROID TREATMENT: Prior to AZA, 49% of CD patients were receiving steroids, whereas only 8% needed steroids after therapy (P < 0.001). Corresponding figures in UC patients were 39% vs. 9% (P < 0.001). HOSPITALIZATIONS: Prior to AZA, the rate of hospitalizations in CD was 0.190 per-patient-year, while after treatment, it decreased to 0.099 (P < 0.001). Corresponding hospitalization rates in UC were 0.108 vs. 0.038 (P < 0.001).

Surgery: The rate of surgery in CD prior/after AZA was 0.038/0.011 per-patient-year (P < 0.001). The number of surgical interventions in UC prior/after AZA treatment was 26/0 (the rate per-patient-year was 0.018/0) (P < 0.001).

Conclusions: Our results confirm the effectiveness of AZA in inflammatory bowel disease, not only in the short term but also in the long term, resulting in a steroid sparing effect and in both a reduction in the number of hospitalizations and surgical procedures. AZA is similarly effective for both CD and UC patients.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Azathioprine / therapeutic use*
  • Epidemiologic Methods
  • Female
  • Humans
  • Immunosuppressive Agents / therapeutic use*
  • Inflammatory Bowel Diseases / drug therapy*
  • Male
  • Treatment Outcome


  • Immunosuppressive Agents
  • Azathioprine