title: Azathioprine for maintaining remission of Crohn's disease.
abstract: OBJECTIVE
  To assess the effectiveness of azathioprine in maintaining remission of quiescent Crohn's disease.
  
  
  METHODS
  Pertinent studies were selected using the MEDLINE data base (1966 - May 1998), the Cochrane Controlled Trials Register, the Inflammatory Bowel Disease Trials Register, as well as abstracts from major gastrointestinal research meetings and references from published articles and reviews.
  
  
  METHODS
  Five randomized, double-blind, placebo-controlled trials of azathioprine therapy were identified. Two of these trials consisted solely of patients with quiescent Crohn's disease. Three trials had multiple therapeutic arms for both induction of remission and maintenance of remission.
  
  
  METHODS
  Data were extracted by three independent observers (GRM, GF, LRS) based on the intention to treat principle. Peto odds ratios for the overall maintenance of remission, steroid sparing, and withdrawals due to adverse effects were calculated, and from these, 95% confidence intervals were derived. Numbers needed to treat or harm (NNT, NNH respectively) for the maintenance of remission, steroid sparing, and withdrawals due to adverse effects were also determined.
  
  
  RESULTS
  Azathioprine had a positive effect on maintaining remission. The Peto odds ratio for maintenance of remission was 2.16 (CI 1.35 - 3.47) with an NNT of 7. A higher dose improved response. A steroid sparing effect was noted, with a Peto odds ratio of 5.22 (CI 1.06 - 25.68) and NNT of 3 for quiescent disease. The Peto odds ratio for withdrawals due to adverse events was 4.36 (CI 1.63 - 11.67), the NNH (Number Needed to Harm) was 19.
  
  
  CONCLUSIONS
  Azathioprine is effective in maintaining remission. There is evidence for a steroid sparing effect.
authors.affiliation: Community Health Sciences, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1. lsutherl@acs.ucalgary.ca
authors.forename: D C
authors.initials: DC
authors.lastname: Pearson
authors.forename: G R
authors.initials: GR
authors.lastname: May
authors.forename: G
authors.initials: G
authors.lastname: Fick
authors.forename: L R
authors.initials: LR
authors.lastname: Sutherland
mesh_terms: D001379:Azathioprine / Q000009:adverse effects / Q000627:therapeutic use*; D003424:Crohn Disease / Q000188:drug therapy / Q000517:prevention & control*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D015122:Mercaptopurine / Q000627:therapeutic use; D011355:Prodrugs / Q000627:therapeutic use
chemical_list: D007166:Immunosuppressive Agents; D011355:Prodrugs; D015122:Mercaptopurine; D001379:Azathioprine