title: The inulin hydrogen breath test predicts the quality of colonic preparation.
abstract: BACKGROUND
  Successful bowel preparation is essential to an adequate performance of colonoscopy. Polyethylene glycol (PEG) with electrolyte solutions induces diarrhea with depletion of substrates fermentable by hydrogen (H2)-producing colonic microbiota. Inulin has recently been suggested as a prebiotic substrate for the H2 breath test because it is resistant to intestinal hydrolysis and is fermented mostly by the colonic bacteria. This study aimed to assess time-dependent changes in H2 breath levels in order to predict the colonic preparation of patients scheduled for colonoscopy with or without oral supplementation of inulin.
  
  
  METHODS
  In this prospective nonrandomized trial, 127 subjects drank 4 l of PEG 280-mg solution as bowel preparation for colonoscopy. A subgroup of 31 patients also ingested inulin (10 g in 200 ml of water) at breakfast as an additional substrate to increase colonic H2 production. Measurements of H2 breath levels were performed immediately before and after colonic preparation. As the main outcome measure, the quality of the colonic preparation was scored as excellent to fair (i.e., clean bowel allowing successful pan-colonoscopy, including the terminal ileum) or poor (incomplete colonoscopy due to fecal debris).
  
  
  RESULTS
  The H2 breath levels decreased from 11.0 ± 1.8 ppm before PEG to 1.8 ± 0.3 ppm after PEG (n = 18; P < 0.001). The H2 concentrations after PEG ingestion were significantly lower (P < 0.001) in the patients with excellent-to-fair preparation than in the 19 patients with poor preparation. Ingestion of inulin induced an overall increase in H2 breath levels and improved discrimination between the patients with excellent-to-fair colonic preparation and those with poor preparation, leading to the sensitivity and specificity of such a test reaching 100 %.
  
  
  CONCLUSIONS
  The H2 breath test with inulin ingestion can be a simple, noninvasive, reliable method for predicting successful colonic preparation that leads to cost savings and less patient discomfort/stress or need to repeat colonoscopy.
authors.affiliation: Department of Emergency and Organ Transplantation, University Aldo Moro of Bari, Bari, Italy, donatofrancesco.altomare@uniba.it.
authors.forename: Donato F
authors.initials: DF
authors.lastname: Altomare
authors.forename: Leonilde
authors.initials: L
authors.lastname: Bonfrate
authors.forename: Marcin
authors.initials: M
authors.lastname: Krawczyk
authors.forename: Frank
authors.initials: F
authors.lastname: Lammert
authors.forename: Onofrio
authors.initials: O
authors.lastname: Caputi-Jambrenghi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Rizzi
authors.forename: Michele
authors.initials: M
authors.lastname: Vacca
authors.forename: Piero
authors.initials: P
authors.lastname: Portincasa
mesh_terms: D001944:Breath Tests / Q000379:methods; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D003113:Colonoscopy / Q000592:standards*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006859:Hydrogen / Q000032:analysis*; D007444:Inulin / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012119:Respiration; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D006859:Hydrogen; D007444:Inulin