title: Reassessment of the principal characteristics of gastroesophageal reflux during the recumbent period using integrated actigraphy-acquired information.
abstract: OBJECTIVE
  Characterization of gastroesophageal reflux (GERD) events during the sleep period has been hampered by lack of any patient-friendly technique that allows accurate assessment of sleep duration and awakening time, without confining patients to a sleep laboratory. Our aim was to compare principal reflux characteristics during the upright, recumbent-awake, and recumbent-asleep periods as well as to determine the effect of sleep awakenings on the principal reflux characteristics of the recumbent-asleep period using novel technology that allows integration of recorded actigraphy data into collected pH information.
  
  
  METHODS
  Patients with heartburn at least three times a week for the previous 3 months were invited to participate in this study. All participants were evaluated by the demographics and the GERD Symptom Checklist questionnaires. Thereafter, patients underwent ambulatory 24-h esophageal pH monitoring concomitantly with actigraphy. A novel technique was used to superimpose simultaneously recorded raw actigraphy data over pH data, resulting in more accurate information about reflux events during upright, recumbent-awake, recumbent-asleep, and conscious awakening periods as well as the relationship between symptoms and acid reflux events in the aforementioned periods.
  
  
  RESULTS
  Thirty-nine subjects (M/F: 26/13, mean age 56.6+/-14 years) with an abnormal pH test were enrolled into the study. The recumbent period appeared heterogeneous and was clearly divided into recumbent-awake (123.0+/-20.2 min) and recumbent-asleep (485.6+/-23.6 min) periods. The percent total time pH<4, the mean number of acid reflux events, and the number of symptoms associated with reflux events were significantly greater in the recumbent-awake as compared with the recumbent-asleep period. The mean duration of an acid reflux event was not different among upright, recumbent-awake, and recumbent-asleep periods. However, short-duration reflux events during the sleep period were associated with conscious awakenings as compared with those during sleep (0.74+/-0.11 min vs. 1.64+/-0.3 min, P=0.01).
  
  
  CONCLUSIONS
  The recumbent period is divided into recumbent-awake and recumbent-asleep periods. The recumbent-awake period has significantly different principal reflux characteristics than the recumbent-asleep period. Duration of an acid reflux event during the recumbent-asleep period is not uniformly prolonged. Short-duration acid reflux events during the sleep period are likely due to conscious awakenings.
authors.affiliation: Department of Medicine, Section of Gastroenterology, Neuroenteric Clinical Research Group, Southern Arizona VA Health Care System, University of Arizona, Tucson, Arizona 85723-0001, USA.
authors.forename: Choo Hean
authors.initials: CH
authors.lastname: Poh
authors.forename: Anita
authors.initials: A
authors.lastname: Gasiorowska
authors.forename: Larissa
authors.initials: L
authors.lastname: Allen
authors.forename: Tomás
authors.initials: T
authors.lastname: Navarro-Rodriguez
authors.forename: Ibraheem
authors.initials: I
authors.lastname: Mizyed
authors.forename: Jeannette
authors.initials: J
authors.lastname: Powers
authors.forename: Bridget
authors.initials: B
authors.lastname: Moty
authors.forename: Stuart F
authors.initials: SF
authors.lastname: Quan
authors.forename: Marcia R
authors.initials: MR
authors.lastname: Willis
authors.forename: Nicole
authors.initials: N
authors.lastname: Ashpole
authors.forename: Isaac
authors.initials: I
authors.lastname: Malagon
authors.forename: Ronnie
authors.initials: R
authors.lastname: Fass
mesh_terms: D056044:Actigraphy / Q000379:methods*; D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D015331:Cohort Studies; D050782:Esophageal pH Monitoring; D004942:Esophagitis, Peptic / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D011336:Probability; D018570:Risk Assessment; D012720:Severity of Illness Index; D012890:Sleep