title: Meta-analysis: the effect of antibiotic resistance status on the efficacy of triple and quadruple first-line therapies for Helicobacter pylori.
abstract: BACKGROUND
  Information regarding the effects of drug resistance on therapies for Helicobacter pylori is limited.
  
  
  OBJECTIVE
  To determine the effect of drug resistance on the efficacy of first-line treatment regimens for H. pylori and identify the most efficacious treatments in the presence of drug resistance.
  
  
  METHODS
  We searched for studies using the keywords: 'Helicobacter pylori','resistance' and 'treatment' or 'therapy'. Multilevel meta-regression models were used to determine the effect of drug resistance on treatment efficacy.
  
  
  RESULTS
  We analysed data from 93 studies with 10,178 participants. For triple therapies, clarithromycin resistance had a greater effect on treatment efficacy than nitroimidazole resistance. Metronidazole resistance reduced efficacy by 26% in triple therapies containing a nitroimidazole, tetracycline and bismuth, while efficacy was reduced by only 14% when a gastric acid inhibitor was added to the regimen. Quadruple therapies containing both clarithromycin and metronidazole were the most efficacious; >80% of H. pylori infections were consistently eradicated with these regimens.
  
  
  CONCLUSIONS
  Drug resistance was a strong predictor of efficacy across triple therapies for the eradication of H. pylori in adults. Resistance to either clarithromycin or metronidazole, but not both simultaneously, may be overcome by using quadruple therapies, especially those containing both clarithromycin and metronidazole.
authors.affiliation: University of North Texas Health Science Center, School of Public Health, Fort Worth, TX 76107, USA. lfischba@hsc.unt.edu
authors.forename: L
authors.initials: L
authors.lastname: Fischbach
authors.forename: E L
authors.initials: EL
authors.lastname: Evans
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D004359:Drug Therapy, Combination; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents