title: [Predominance of constipation in subjects with hydrogen-consuming intestinal flora].
abstract: BACKGROUND
  There is growing evidence that a disorder in intestinal microbiota would contribute to the development of symptoms in irritable bowel syndrome (IBS) patients. In a subgroup, a remarkably low hydrogen production in lactulose breath test (LBT) is observed. We presume in these patients a predominance of hydrogen consuming gut flora.
  
  
  OBJECTIVE
  [corrected] Describe the clinical presentation of lBS patients with low hydrogen production and to compare their cathartic pattern against those with high hydrogen excretion.
  
  
  METHODS
  A case-control study was designed. IBS outpatients were included. A validated questionnaire was delivered (IBSSS) in order to assess their symptoms and a LBT was performed. The cathartic pattern was compared between those with low and high hydrogen production on LBT.
  
  
  RESULTS
  One hundred and ten patients were included and 15 of them (13.6%) had low hydrogen production on LBT, which would be compatible with the presence of hydrogen-consuming gut flora. In this group, 11 patients (73.33%) were constipated In contrast, only 30 patients (31.58%) in the high or normal hydrogen production group were constipated [OR 5.95 (95% confidence interval 1.75-20.25; P = 0.03)].
  
  
  CONCLUSIONS
  IBS patients with low hydrogen production on lactulose breath test were 6 times more frequently constipated.
authors.affiliation: Servicio de Gastroenterología, Departamento de Medicina Interna, CEMIC Ciudad Autómoma de Buenos Aires, Argentina.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Dima
authors.forename: Daniel
authors.initials: D
authors.lastname: Peralta
authors.forename: Abel
authors.initials: A
authors.lastname: Novillo
authors.forename: Juan
authors.initials: J
authors.lastname: Lasa
authors.forename: Horacio
authors.initials: H
authors.lastname: Besasso
authors.forename: Luis
authors.initials: L
authors.lastname: Soifer
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000378:metabolism*; D001944:Breath Tests; D016022:Case-Control Studies; D003248:Constipation / Q000382:microbiology*; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D043183:Irritable Bowel Syndrome / Q000378:metabolism / Q000382:microbiology*; D007792:Lactulose; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D007792:Lactulose; D006859:Hydrogen