title: Systematic review and meta-analysis: full- vs. half-dose anti-microbials in clarithromycin-based regimens for Helicobacter pylori eradication.
abstract: BACKGROUND
  Half-dose regimens may be equally effective but associated with diminished adverse events (AE) than standard-dose regimens.
  
  
  OBJECTIVE
  To assess efficacy and safety of full- vs. half-dose clarithromycin in the treatment of H. pylori.
  
  
  METHODS
  Medline, EMBASE and PubMed databases were searched for randomised controlled trials (RCTs) that meet eligibility criteria. Only parallel group RCTs with ≥ 2 arms were eligible. Studies comparing triple, quadruple or sequential therapy for 7-14 days were selected. Regimens had to contain the same drug combination, differing only in dosage; the comparison of full- vs. half-dose clarithromycin was required, regardless if other drugs were dose-reduced or not. Data extraction was performed for primary outcome [eradication by intent-to-treat (ITT) and per-protocol (PP) analyses] and secondary outcome (AE).
  
  
  RESULTS
  A total of 1622 articles were identified, of which 19 studies were eligible. Overall, eradication was achieved in 82.5% of half-dose (n = 2115) vs. 83.4% of full-dose recipients (n = 2109) on ITT (87.1% vs. 88.4% on PP respectively). Pooled relative risk in the half- vs. full-dose regimen was 0.98 (95% CI: 0.95-1.02) on ITT and 0.99 (95% CI: 0.97-1.01) on PP by the random effects model. Heterogeneity was significant (chi-squared statistic P = 0.05, I(2) = 37%). AE were reported in 29.3% of half- vs. 44.0% of full-dose recipients [pooled RR 0.67 (95% CI: 0.60-0.75)]. Pre-planned subgroup analyses of dose modification, sample size, study origin and treatment duration, as well as sensitivity analysis showed no significant differences between arms.
  
  
  CONCLUSIONS
  A half-dose clarithromycin-based regimen is equally effective yet better tolerated than its full-dose counterpart in the treatment of H. pylori.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: A H
authors.initials: AH
authors.lastname: Harb
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: J M
authors.initials: JM
authors.lastname: Chalhoub
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: R
authors.initials: R
authors.lastname: Abou Mrad
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: A I
authors.initials: AI
authors.lastname: Sharara
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D017291:Clarithromycin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori; D006801:Humans; D016032:Randomized Controlled Trials as Topic
chemical_list: D000900:Anti-Bacterial Agents; D017291:Clarithromycin