title: Gastroesophageal reflux and sleep events in obstructive sleep apnea.
abstract: OBJECTIVE
  Gastroesophageal reflux disease (GERD) and obstructive sleep apnea (OSA) often coexist. We sought to determine the presence and direction of any association between GERD and sleep events in patients with OSA.
  
  
  METHODS
  We conducted a case-crossover study among 18 patients with known OSA and GERD. All study patients underwent overnight simultaneous polysomnography and esophageal pH monitoring. A series of case-crossover analyses was conducted by defining each of the sleep (i.e. arousal, awakening, and apnea) and gastroesophageal reflux (GER) events as the outcome in turn. Respective control time points were randomly selected in all eligible control periods. When a sleep event was the outcome, the GER event was the exposure of interest. When GER was the outcome, each sleep event was assessed as the exposure individually. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  Both awakenings and arousals were significantly associated with the subsequent onset of a GER event. The OR for a GER event following an awakening was 5 (95% CI 3.6-6.9) and for a GER event following an arousal was 2.5 (95% CI 1.8-3.4). Apnea did not lead to GER (OR 1.0, 95% CI 0.8-1.4). GER was not more commonly observed before any of the sleep events compared with control periods without sleep events.
  
  
  CONCLUSIONS
  In patients with coexisting GERD and OSA, both awakening and arousal preceded GER events, but GER does not appear to precipitate sleep-related events.
authors.affiliation: aDepartment of Medicine, Division of Gastroenterology bDepartment of Medicine, Division of Sleep Medicine cCenter for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Yu-Xiao
authors.initials: YX
authors.lastname: Yang
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Spencer
authors.forename: Sharon
authors.initials: S
authors.lastname: Schutte-Rodin
authors.forename: Colleen
authors.initials: C
authors.lastname: Brensinger
authors.forename: David C
authors.initials: DC
authors.lastname: Metz
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D017286:Polysomnography; D012307:Risk Factors; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis; D012893:Sleep Wake Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors; D014851:Wakefulness