title: Meta-analysis: the efficacy of azathioprine and mercaptopurine in ulcerative colitis.
abstract: BACKGROUND
  Debate exists regarding to whether thiopurine therapy is as effective in ulcerative colitis (UC) as it is in Crohn's disease.
  
  
  OBJECTIVE
  To review systematically the efficacy of azathioprine (AZA) and mercaptopurine (MP) in UC, and to conduct a meta-analysis of randomized clinical trials evaluating the efficacy of AZA/MP for the induction or maintenance of UC clinical remission.
  
  
  METHODS
  
  
  
  METHODS
  Evaluating AZA/MP for induction and/or maintenance of clinical remission of UC. Randomized-controlled-trials comparing AZA/MP with placebo/5-aminosalicylates were included in the meta-analysis.
  
  
  METHODS
  Electronic and manual. Study quality: Independently assessed by two reviewers.
  
  
  RESULTS
  By 'intention-to-treat'.
  
  
  RESULTS
  Thirty noncontrolled studies (1632 patients) were included in the systematic review. Mean efficacy of AZA/MP was 65% for induction and 76% for maintenance of the remission. Seven controlled studies were included in the meta-analysis. (i) Induction of remission: four studies (89 AZA/MP-treated patients) showed mean efficacy of 73% vs. 64% in controls (OR = 1.59; 95% CI = 0.59-4.29). (ii) Maintenance of remission: six studies (124 AZA/MP-treated patients) showed mean efficacy of 60% vs. 37% in controls (OR = 2.56; 95% CI = 1.51-4.34). When only studies comparing AZA/MP vs. placebo were considered, OR was 2.59 (95% CI = 1.26-5.3), absolute risk reduction was 23% and number-needed-to-treat (NNT) to prevent one recurrence was 5.
  
  
  CONCLUSIONS
  Thiopurine drugs (AZA/MP) are more effective than placebo for the prevention of relapse in UC, with an NNT of 5 and an absolute risk reduction of 23%.
authors.affiliation: Gastroenterology Unit, Hospital Universitario de la Princesa, Madrid, Spain. gisbert@meditex.es
authors.forename: J P
authors.initials: JP
authors.lastname: Gisbert
authors.forename: P M
authors.initials: PM
authors.lastname: Linares
authors.forename: A G
authors.initials: AG
authors.lastname: McNicholl
authors.forename: J
authors.initials: J
authors.lastname: Maté
authors.forename: F
authors.initials: F
authors.lastname: Gomollón
mesh_terms: D001379:Azathioprine / Q000627:therapeutic use*; D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000517:prevention & control; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D015122:Mercaptopurine / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D012074:Remission Induction; D055502:Secondary Prevention; D016896:Treatment Outcome
chemical_list: D007166:Immunosuppressive Agents; D015122:Mercaptopurine; D001379:Azathioprine