title: Helicobacter pylori infection treatment of nonulcer dyspepsia: an analysis of meta-analyses.
abstract: BACKGROUND
  Meta-analysis is often used to resolve uncertainty in magnitude of effect between studies. However, several meta-analyses investigating the association between Helicobacter pylori infection and nonulcer dyspepsia reported contradictory results.
  
  
  OBJECTIVE
  To perform a systematic review of the conflicting data in meta-analyses examining the association between H. pylori infection and nonulcer dyspepsia.
  
  
  METHODS
  Five meta-analyses were identified: three studied the relation between H. pylori treatment and nonulcer dyspepsia, one studied the relation between H. pylori eradication and nonulcer dyspepsia, and one reported both. Data on search strategy, study selection, study inclusion, data abstraction, reported results of included studies, and summarized effect estimates were collected.
  
  
  RESULTS
  Overall, 29 studies were included in the five meta-analyses. Nine studies (31%) were evaluated in more than one meta-analysis. There was no disagreement between the meta-analyses concerning the interpretation of outcome per investigated study; the results from seven (24%) studies showed improvement of dyspeptic symptoms after H. pylori treatment or eradication. The odds ratio of symptom relief in the control groups relative to the treated groups varied between 0.30 (95% CI = 0.2-0.5) to 0.88 (95% CI = 0.7-1.2). The proportion of patients' symptom free due to H. pylori treatment varied between 11% and 38%.
  
  
  CONCLUSIONS
  The reported conflicting results between the meta-analyses were mainly a result of differences in study selection (eligibility and quality criteria) and relatively small. In a subgroup of patients with nonulcer dyspepsia, H. pylori eradication is useful for relief of symptoms.
authors.affiliation: Department of Gastroenterology, UMC St. Radboud, Nijmegen, The Netherlands. R.Laheij@mdl.umcn.nl
authors.forename: R J F
authors.initials: RJ
authors.lastname: Laheij
authors.forename: L G M
authors.initials: LG
authors.lastname: van Rossum
authors.forename: A L M
authors.initials: AL
authors.lastname: Verbeek
authors.forename: J B M J
authors.initials: JB
authors.lastname: Jansen
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D015897:Comorbidity; D016001:Confidence Intervals; D004415:Dyspepsia / Q000188:drug therapy* / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005500:Follow-Up Studies; D016481:Helicobacter Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents