title: Helicobacter pylori, HIV and Gastric Hypochlorhydria in the Malawian Population.
abstract: BACKGROUND
  HIV and Helicobacter pylori are common chronic infections in sub-Saharan Africa. Both conditions can predispose to gastric hypochlorhydria that may be a risk factor for enteric infections and reduced drug absorption. We have investigated to what extent HIV and H. pylori infections are associated with hypochlorhydria in a Malawian cohort of patients undergoing endoscopy.
  
  
  METHODS
  104 sequential symptomatic adults referred for gastroscopy at Queen Elizabeth Central Hospital, Blantyre, Malawi, had blood taken for rapid HIV testing and fasting serum gastrin analysis. Gastric fluid was aspirated for pH testing, and gastric biopsies were taken.
  
  
  RESULTS
  After 9/104 HIV-infected patients who were already established on anti-retroviral therapy were excluded, 17/95 (25.0%) were seropositive for untreated HIV, and 68/95 (71.6%) patients were H. pylori positive by histology. Hypochlorhydria (fasting gastric pH>4.0) was present in 55.8% (53/95) of patients. H. pylori infection was significantly associated with hypochlorhydria (OR 2.91, [1.02-7.75], p=0.046). While single infection with HIV was not significantly independently associated with hypochlorhydria. H. pylori and HIV co-infection was more strongly associated with hypochlorhydria (OR 6.25, [1.33-29.43], p=0.020) than either infection alone, suggesting an additive effect of co-infection. HIV infection was associated with higher serum gastrin levels (91.3 pM vs. 53.1 pM, p=0.040), while H. pylori infection was not (63.1 pM vs. 55.1 pM, p=0.610). Irrespective of H. pylori and HIV status, most patients (>90%) exhibited pangastritis. Only three patients had histological evidence of gastric atrophy, of which only one was HIV-infected.
  
  
  CONCLUSIONS
  H. pylori infection was associated with fasting hypochlorhydria, while HIV was not independently associated. HIV and H. pylori co-infection, however, was more strongly associated with hypochlorhydria than H. pylori infection alone. The mechanism of this apparent additive effect between HIV and H. pylori remains unclear, but appears to be related to chronic pangastritis rather than gastric atrophy, and associated with hypergastrinaemia in HIV-infected individuals.
authors.affiliation: Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Joe
authors.initials: J
authors.lastname: Geraghty
authors.affiliation: Department of Surgery, College of Medicine, Blantyre, Malawi.
authors.forename: Alexander
authors.initials: A
authors.lastname: Thumbs
authors.affiliation: Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Blantyre 3, Malawi; Department of Medicine, College of Medicine, Blantyre, Malawi.
authors.forename: Anstead
authors.initials: A
authors.lastname: Kankwatira
authors.affiliation: Department of Pathology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Tim
authors.initials: T
authors.lastname: Andrews
authors.affiliation: Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Moore
authors.affiliation: Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Blantyre 3, Malawi.
authors.forename: Rose
authors.initials: R
authors.lastname: Malamba
authors.affiliation: Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Blantyre 3, Malawi.
authors.forename: Neema
authors.initials: N
authors.lastname: Mtunthama
authors.affiliation: Department of Surgery, College of Medicine, Blantyre, Malawi.
authors.forename: Kai
authors.initials: K
authors.lastname: Hellberg
authors.affiliation: Department of Surgery, College of Medicine, Blantyre, Malawi.
authors.forename: Lughano
authors.initials: L
authors.lastname: Kalongolera
authors.affiliation: Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: O'Toole
authors.affiliation: Department of Cellular and Molecular Physiology, University of Liverpool, United Kingdom.
authors.forename: Andrea
authors.initials: A
authors.lastname: Varro
authors.affiliation: Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: D Mark
authors.initials: DM
authors.lastname: Pritchard
authors.affiliation: Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Blantyre 3, Malawi; Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom; Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Melita
authors.initials: M
authors.lastname: Gordon
mesh_terms: D000126:Achlorhydria / Q000175:diagnosis / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D060085:Coinfection / Q000150:complications; D005260:Female; D005744:Gastric Acid; D005773:Gastroscopy; D015658:HIV Infections / Q000150:complications*; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D006801:Humans; D008295:Malawi; D008297:Male; D008875:Middle Aged; D055815:Young Adult