title: Association of Helicobacter pylori infection with hepatic encephalopathy risk: a systematic review.
abstract: BACKGROUND
  The role of Helicobacter pylori (H. pylori) in the pathogenesis of hepatic encephalopathy (HE) is still under debate. We reviewed the available evidence for a pathogenic role of H. pylori infection in determining HE in cirrhotic patients.
  
  
  METHODS
  We searched PubMed, EMBASE, and Cochrane Library prior to 2012 for studies that explored the role of H. pylori in HE pathogenesis.
  
  
  RESULTS
  Twenty studies were eligible for our analysis. Eleven studies investigated the epidemiology of H. pylori infection; there is evidence suggesting that the prevalence of H. pylori is higher in older HE patients. The evidence of nine studies failed to find that blood ammonia level was higher in H. pylori positive cirrhotic patients than in negative patients. Four studies suggested that gastric ammonia level was higher in H. pylori positive than H. pylori negative patients. Eleven studies investigated the effect of H. pylori eradication on the change of blood ammonia levels and the HE improvement. No new reliable evidence was found to support the effect of H. pylori eradication in reducing blood ammonia levels and improving HE symptoms.
  
  
  CONCLUSIONS
  Current evidence confirmed the higher prevalence of H. pylori infection in HE patients. However, no new evidence supported the effect of H. pylori on the increased of blood ammonia level, nor the efficacy of H. pylori eradication in decreasing of blood ammonia level and improving HE.
authors.affiliation: Guangxi Medical Information Institute, Dong-Ge Road 20-7, Nanning 530022, Guangxi, PR China.
authors.forename: Bang-Li
authors.initials: BL
authors.lastname: Hu
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Wang
authors.forename: Guang-Ye
authors.initials: GY
authors.lastname: Yang
mesh_terms: D000641:Ammonia / Q000032:analysis*; D016481:Helicobacter Infections / Q000097:blood* / Q000150:complications; D016480:Helicobacter pylori; D006501:Hepatic Encephalopathy / Q000097:blood* / Q000150:complications; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood* / Q000150:complications; D015995:Prevalence; D018570:Risk Assessment; D013270:Stomach / Q000737:chemistry
chemical_list: D000641:Ammonia