title: Systematic review and meta-analysis: importance of CagA status for successful eradication of Helicobacter pylori infection.
abstract: BACKGROUND
  Some, but not all studies have provided evidence that the CagA status of Helicobacter pylori strains is a predictive factor for the outcome of eradication therapy.
  
  
  OBJECTIVE
  To clarify the association between CagA status and eradication outcome.
  
  
  METHODS
  We included studies reporting the numbers of successful and failed cases in H. pylori-eradication therapy according to the CagA status. Fourteen studies (1529 patients) were included of 325 articles identified in the search. The pooled risk ratio for H. pylori-eradication failure in CagA-negative relative to CagA-positive strains and the pooled risk difference in eradication success between the two groups were used as summary statistics. Meta-regression was used for examining the source of heterogeneity.
  
  
  RESULTS
  The summary risk ratio for eradication failure in CagA-negative relative to CagA-positive was 2.0 (95% CI: 1.6-2.4, P < 0.001), corresponding with the summary risk difference for eradication success between the groups of 11% (95% CI: 3-19%, P = 0.011). Meta-regression analysis demonstrated that usage of polymerase chain reaction examination for CagA status and a high proportion of non-ulcer dyspepsia patients were factors for heterogeneity among studies.
  
  
  CONCLUSIONS
  Our meta-analysis confirmed the importance of the presence of CagA as a predictor for successful eradication of H. pylori.
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Matsuo
authors.forename: A
authors.initials: A
authors.lastname: Sawaki
authors.forename: H
authors.initials: H
authors.lastname: Ito
authors.forename: K
authors.initials: K
authors.lastname: Hirose
authors.forename: K
authors.initials: K
authors.lastname: Wakai
authors.forename: S
authors.initials: S
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Yamao
authors.forename: R
authors.initials: R
authors.lastname: Ueda
authors.forename: K
authors.initials: K
authors.lastname: Tajima
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D016481:Helicobacter Infections / Q000235:genetics* / Q000517:prevention & control; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori