Reassessment of the Principal Characteristics of Gastroesophageal Reflux During the Recumbent Period Using Integrated Actigraphy-Acquired Information

OBJECTIVES: 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.