title: Relapse rate following azathioprine withdrawal in maintaining remission for Crohn's disease: a meta-analysis.
abstract: BACKGROUND
  The duration of use of azathioprine (Aza) and 6-mercaptopurine (6-MP) for maintaining remission for Crohn's disease is debatable.
  
  
  OBJECTIVE
  To examine whether Aza/6-MP can be safely withdrawn in patients with Crohn's disease who have been in remission.
  
  
  METHODS
  The following databases were searched: MEDLINE (1950-September 2010), EMBASE (1980-September 2010), CINHAL (1981-September 2010), PubMed (1950-September 2010), and the Cochrane Central Register of Controlled Trials (CENTRAL). Randomised controlled and cohort studies comparing azathioprine continuation versus placebo or no treatment were eligible for inclusion. Primary outcomes were relapse rate after discontinuation of Aza/6-MP at 6, 12, and 18 months, and 5 and 10 years.
  
  
  RESULTS
  Five studies, with 256 patients and 168 controls, met the inclusion criteria. Stopping azathioprine/6-MP was found to significantly increase the risk of relapse at 6, 12, and 18 months with pooled odds ratios of 0.22 (95% CI 0.09-0.53), 0.25 (95% CI 0.11-0.56), and 0.35 (95% CI 0.21-0.6), respectively. Two trials examined relapse rate at 5 years with pooled OR 0.53 (95% CI 0.13-2.21). No trials looking at relapse rates beyond 5 years were identified.
  
  
  CONCLUSIONS
  There is a clear benefit of continuing Aza/6-MP for at least 18 months to maintain remission for Crohn's disease patients who established remission. There is not enough evidence to provide clear guidance on whether or not to continue Aza/6-MP treatment beyond 18 months. Well-designed randomised controlled trials addressing this issue are needed.
authors.affiliation: Division of Paediatric Gastroenterology, Hepatology and Nutrition, Alder Hey Children's NHS Foundation Trust, Eaton Road, Liverpool, L12 2AP, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: French
authors.forename: A
authors.initials: A
authors.lastname: Mark Dalzell
authors.forename: Ramesh
authors.initials: R
authors.lastname: Srinivasan
authors.forename: Wael
authors.initials: W
authors.lastname: El-Matary
mesh_terms: D001379:Azathioprine / Q000627:therapeutic use*; D003424:Crohn Disease / Q000188:drug therapy*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D012074:Remission Induction; D016896:Treatment Outcome; D028761:Withholding Treatment
chemical_list: D007166:Immunosuppressive Agents; D001379:Azathioprine