title: "Normal Values of 24H Multichannel Intraluminal Impedance pH-Metry in a Greek Obese Population Based on Montreal Definition of Gerd".
abstract: BACKGROUND
  Although several studies reporting normal values of 24h multichannel intraluminal impedance pH (MIIpH) have been published, none of them has ever studied obese individuals. The purpose of this study is to determine overall frequency and duration of reflux episodes (acid and non-acid, supine-upright, post and preprandial) in obese asymptomatic volunteers.
  
  
  METHODS
  Obese volunteers were enlisted during their preoperative evaluation for bariatric surgery. Volunteers had no gastroesophageal reflux disease (GERD) symptoms and no evidence of esophageal mucosal injury on endoscopy. Participants underwent a 24h MIIpH.
  
  
  RESULTS
  In this prospective observational study, data of 22 obese individuals were analyzed. Mean age was 41.9 years and mean BMI was 47.1 kg/m(2). Mean total reflux episodes was 55.6 and 95th percentile was 99.7. Mean percentage of total time with pH <4 was 2.59 % and 95th percentile was 8.57 %. Mean percentage of bolus exposure was 1.84 % with 95th percentile being 4.47 %. Postprandial acid reflux episodes were statistical significant more frequent in comparison to preprandial acid reflux episodes (19.41 vs. 15, p = 0.008). Mean acid clearance duration was 3.6 times higher than median bolus clearance duration (56.05 and 15.55 s, respectively, p = 0.868).
  
  
  CONCLUSIONS
  Our study is the first to provide normal values of 24h MIIpH of asymptomatic obese. Normal values of 24h MIIpH of obese asymptomatic individuals differ from the reported normal values of non-obese healthy individuals; having more reflux episodes and equal or slightly higher median bolus exposure and acid clearance. Our results imply that new cut-off values should be employed in order to define GERD in obese individuals.
authors.affiliation: Department of Foregut Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, 114 Vas. Sofias Av., 11527, Athens, Greece. tzinagb@yahoo.gr.
authors.forename: Georgia
authors.initials: G
authors.lastname: Doulami
authors.affiliation: Department of Foregut Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, 114 Vas. Sofias Av., 11527, Athens, Greece.
authors.forename: Stamatina
authors.initials: S
authors.lastname: Triantafyllou
authors.affiliation: Department of Bariatric Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Natoudi
authors.affiliation: Department of Bariatric Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Albanopoulos
authors.affiliation: Department of Bariatric Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Menenakos
authors.affiliation: 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Filis
authors.affiliation: 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Zografos
authors.affiliation: Department of Foregut Surgery, 1st Propaedeutic Surgical Clinic, "Hippokration" General Hospital of Athens, National and Kapodistrian University of Athens, 114 Vas. Sofias Av., 11527, Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Theodorou
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D017097:Electric Impedance; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D012016:Reference Values
keywords: 24h MIIpH; GERD; Normal values