title: Subjective apnoea symptoms are associated with daytime sleepiness in patients with moderate and severe obstructive sleep apnoea: a retrospective study.
abstract: OBJECTIVE
  Most previous studies have failed to show a relation between daytime sleepiness and apnoea severity in patients with obstructive sleep apnoea (OSA). We determined the relation between daytime sleepiness and subjective and objective apnoea severity in newly diagnosed patients with moderate-to-severe OSA.
  
  
  METHODS
  Retrospective cross-sectional study.
  
  
  METHODS
  Tertiary referral centre.
  
  
  METHODS
  A total of 559 adults with newly diagnosed moderate and severe OSA.
  
  
  METHODS
  Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). Subjective and objective apnoea severities were assessed using the Sleep Breathing Scale (SBS) and polysomnography respectively. Sleep quality and depressive symptoms were evaluated using Medical Outcomes Study-Sleep Scale and Beck Depression Inventory (BDI) respectively.
  
  
  RESULTS
  The mean ESS score was 9.8 (SD 5.0). ESS score was correlated with SBS score (P < 0.001), apnoea-hypopnoea index (AHI) (P = 0.027), minimal oxygen saturation (MinSaO2 ) (P = 0.021), body mass index (BMI) (P = 0.007) and BDI score (P < 0.001). Linear regression analysis showed that higher SBS (P = 0.005) and BDI scores (P < 0.001) were associated with higher ESS score after controlling for gender, BMI and AHI. Apnoea-hypopnoea index, MinSaO2 and BMI were not independently related to ESS score.
  
  
  CONCLUSIONS
  Daytime sleepiness was related to subjective OSA symptoms but not objective apnoea severity measured by polysomnography in patients with moderate-to-severe OSA. These findings suggest the usefulness of the subjective apnoea severity as an indicator of OSA disease severity.
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Ryu
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: S A
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: G H
authors.initials: GH
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Chung
authors.affiliation: Department of Pulmonary Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: W S
authors.initials: WS
authors.lastname: Kim
mesh_terms: D003430:Cross-Sectional Studies; D003863:Depression / Q000175:diagnosis; D006970:Disorders of Excessive Somnolence / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications*