title: Is Helicobacter pylori infection associated with Henoch-Schonlein purpura in Chinese children? a meta-analysis.
abstract: BACKGROUND
  The prevalence of Helicobacter pylori (H. pylori) infection is high in China. It not only causes the damage of gastric epithelium, but also plays a potential pathogenic role in several extraintestinal diseases. Henoch-Schonlein purpura (HSP) is one of the most common vasculitis syndromes affecting children. Although its cause is unclear, HSP is often considered to be associated with infectious agents. This metaanalysis of previously published studies was conducted using a predefined protocol to evaluate the underlying association between H. pylori infection and HSP in Chinese children.
  
  
  METHODS
  Predefined search strategy and inclusion criteria were set up to select studies reporting the prevalence of H. pylori infection among HSP children and control groups. Included studies were subjected to quality assessment and data extraction by two independent reviewers. The pooled odds ratio (OR) was calculated as the effect size via both traditional and cumulative meta-analysis. Heterogeneity was investigated by subgroup analysis, and the nonparametric "trim and fill" method was performed to adjust the overall estimate for the existence of publication bias.
  
  
  RESULTS
  Ten eligible studies covering 749 HSP children and 560 controls were included for metaanalysis. Observational epidemiology studies clearly aimed at detecting the potential association between H. pylori infection and HSP with retrospective data collection from the children enrolled consecutively. Overall, 49.27% (369/749) of HSP children had evidence of H. pylori infection compared with 23.39% (131/560) of children in the control group. The pooled OR of H. pylori infection in HSP children (10 studies with 749 HSP children) was 3.80 [95% confidence interval (CI): 2.54-5.68, P<0.001], and the overall estimate from the cumulative meta-analysis confirmed the association with more narrow confidence interval (OR=3.35, 95% CI: 2.95-3.81). In HSP children mainly with abdominal manifestations (8 studies with 337 HSP children), the pooled OR was 4.62 (95% CI: 2.66-8.01, P<0.001). The adjusted pooled OR was 2.04 (95% CI: 1.48-2.82, P<0.001), determined by the nonparametric "trim-andfill" method for eliminating the effect of publication bias. H. pylori eradication therapy (4 studies with 266 HSP children) was capable of reducing the recurrence of HSP (RR=0.38, 95% CI: 0.25-0.58, P<0.001). Although the subgroup analysis for heterogeneity suggested that diagnostic methods and geographical diversity might be account for the heterogeneity, statistical analysis of differences revealed no differences between subgroups, indicating their limited impact on the overall estimates.
  
  
  CONCLUSIONS
  These results suggest the necessity of screening H. pylori infection in HSP children, particularly in those with gastrointestinal manifestations in China. Eradication therapy may reduce the recurrence of HSP in children with H. pylori infection. However, further mechanistic and more clinical studies in different populations and regions are needed to confirm this association and the effect of eradication of H. pylori in HSP children.
authors.affiliation: Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.
authors.forename: Li-Jing
authors.initials: LJ
authors.lastname: Xiong
authors.forename: Yu
authors.initials: Y
authors.lastname: Tong
authors.forename: Zhi-Ling
authors.initials: ZL
authors.lastname: Wang
authors.forename: Meng
authors.initials: M
authors.lastname: Mao
mesh_terms: D002681:China; D015897:Comorbidity; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000276:immunology; D016480:Helicobacter pylori; D011695:IgA Vasculitis / Q000453:epidemiology* / Q000276:immunology