title: Effect of Helicobacter pylori eradication on platelet count in idiopathic thrombocytopenic purpura: a systematic review and meta-analysis.
abstract: BACKGROUND
  There is a debate in the recent literature about the effect of Helicobacter pylori eradication on platelet count in patients with idiopathic thrombocytopenic purpura (ITP). In order to clarify this controversial issue, we performed a systematic review with meta-analysis of the available literature.
  
  
  METHODS
  The meta-analytic comparison was focused on the difference in the platelet count increase between the experimental arm (H. pylori-infected patients who responded to eradication therapy) and each control arm (H. pylori-infected patients who failed to respond to eradication therapy; H. pylori-infected patients who did not receive eradication therapy and H. pylori-negative patients) and was expressed as weighted mean difference (WMD). Moreover, in order to explain the heterogeneity, a meta-regression model was fitted with arm-level covariates.
  
  
  RESULTS
  Data involving 788 ITP patients were collected from 17 articles (16 studies with a prospective cohort design and 1 randomized trial). There was a statistically significant difference in the increase in platelet count in patients in whom eradication was successful compared with control groups [WMD, 40.77x10(9)/L (95% CI, 20.92-60.63) compared with untreated patients; 52.16 (95% CI, 34.26-70.05) compared with patients who failed eradication and 46.35 (95% CI, 27.79-64.91) compared with H. pylori-negative patients]. Moreover, in the meta-regression model, the success of H. pylori eradication was highly significant as an explanatory variable for platelet count increase.
  
  
  CONCLUSIONS
  Our analysis shows a strict correlation between H. pylori eradication and increase in platelet count. However, due to intrinsic limits in the design of the studies analysed, further evidence from randomized clinical trials is required to confirm the effect of eradication treatment on platelet count.
authors.affiliation: Immuno-Hematology and Transfusion Center, City Hospital, Verona, and Department of Histology, Microbiology, and Medical Biotechnology, University of Padua, Italy. massimo.franchini@azosp.vr.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Franchini
authors.forename: Mario
authors.initials: M
authors.lastname: Cruciani
authors.forename: Carlo
authors.initials: C
authors.lastname: Mengoli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pizzolo
authors.forename: Dino
authors.initials: D
authors.lastname: Veneri
mesh_terms: D003625:Data Collection; D016481:Helicobacter Infections / Q000097:blood* / Q000150:complications / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D010976:Platelet Count; D017594:Publication Bias; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood* / Q000150:complications; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012044:Regression Analysis