title: Meta-analysis: the effects of placebo treatment on gastro-oesophageal reflux disease.
abstract: BACKGROUND
  There appears to be a significant placebo response rate in clinical trials for gastro-oesophageal reflux disease. Little is known about the determinants and the circumstances associated with placebo response in the treatment of gastro-oesophageal reflux disease (GERD).
  
  
  OBJECTIVE
  To estimate the magnitude of the placebo response rate in randomized controlled trials for GERD and to identify factors that influence this response.
  
  
  METHODS
  A meta-analysis of randomized, double-blind, placebo-controlled trials, published in English language, which included >20 patients with GERD, treated with either a proton pump inhibitor or H(2)-receptor antagonist for at least 2 weeks. Medline, Cochrane and EMBASE databases were searched, considering only studies that reported a global response for 'heartburn'.
  
  
  RESULTS
  A total of 24 studies included 9989 patients with GERD. The pooled odds ratio (OR) for response to active treatment vs. placebo was 3.71 (95% CI: 2.78-4.96). The pooled estimate of the overall placebo response was 18.85% (range 2.94%-47.06%). Patients with erosive oesophagitis had a non-significantly lower placebo response rate than patients without it (11.87% and 18.31%, respectively; P = 0.246). Placebo response was significantly lower in studies of PPI therapy vs. studies of H(2) RAs (14.51% vs. 24.69%, respectively; P = 0.05).
  
  
  CONCLUSIONS
  The placebo response rate in randomized controlled trials for GERD is substantial. A lower placebo response was associated with the testing of PPIs, but not the presence of erosive oesophagitis.
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: F
authors.initials: F
authors.lastname: Cremonini
authors.forename: D C
authors.initials: DC
authors.lastname: Ziogas
authors.forename: H Y
authors.initials: HY
authors.lastname: Chang
authors.forename: E
authors.initials: E
authors.lastname: Kokkotou
authors.forename: J M
authors.initials: JM
authors.lastname: Kelley
authors.forename: L
authors.initials: L
authors.lastname: Conboy
authors.forename: T J
authors.initials: TJ
authors.lastname: Kaptchuk
authors.forename: A J
authors.initials: AJ
authors.lastname: Lembo
mesh_terms: D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D005765:Gastrointestinal Agents / Q000627:therapeutic use*; D006801:Humans; D015990:Placebo Effect; D010919:Placebos / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D013223:Statistics as Topic; D016896:Treatment Outcome
chemical_list: D005765:Gastrointestinal Agents; D010919:Placebos