title: Continuous positive airway pressure reduces daytime sleepiness in mild to moderate obstructive sleep apnoea: a meta-analysis.
abstract: BACKGROUND
  Obstructive sleep apnoea syndrome (OSAS) affects an estimated 2-4% of the middle aged population. Meta-analyses of randomised controlled trials have shown that the severe presentation of the syndrome (apnoea hypopnoea index (AHI) >30/hour) is effectively treated with continuous positive airway pressure (CPAP). Until recently there have been insufficient data to determine whether CPAP improves sleepiness in the larger subgroup with mild to moderate OSAS (AHI 5-30/hour).
  
  
  METHODS
  A systematic search of Medline and a hand search identified seven randomised controlled trials where CPAP was compared with either a placebo or with conservative management in the treatment of mild to moderate OSAS (AHI 5-30/hour). All trials used the Epworth Sleepiness Scale (ESS), four used the Multiple Sleep Latency Test (MSLT), and three used the Maintenance of Wakefulness Test (MWT) to measure sleepiness.
  
  
  RESULTS
  Meta-analyses indicated that CPAP significantly reduced subjective daytime sleepiness (ESS) by 1.2 points (95% CI 0.5 to 1.9, p = 0.001), improved objective daytime wakefulness (MWT) by 2.1 minutes (95% CI 0.5 to 3.7, p = 0.011), but did not affect objective daytime sleepiness (MSLT, mean benefit -0.2 minutes, 95% CI -1.0 to 0.6, p = 0.6). The two significant effects were small (effect size <0.30).
  
  
  CONCLUSIONS
  CPAP elicits small improvements in subjective sleepiness and objective wakefulness in people with mild to moderate OSAS. However, the effects on sleepiness are of limited clinical significance.
authors.affiliation: Sleep/Wake Research Centre, Massey University, New Zealand. nmarshall@woolcock.org.au
authors.forename: N S
authors.initials: NS
authors.lastname: Marshall
authors.forename: M
authors.initials: M
authors.lastname: Barnes
authors.forename: N
authors.initials: N
authors.lastname: Travier
authors.forename: A J
authors.initials: AJ
authors.lastname: Campbell
authors.forename: R J
authors.initials: RJ
authors.lastname: Pierce
authors.forename: R D
authors.initials: RD
authors.lastname: McEvoy
authors.forename: A M
authors.initials: AM
authors.lastname: Neill
authors.forename: P H
authors.initials: PH
authors.lastname: Gander
mesh_terms: D000328:Adult; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D007319:Sleep Initiation and Maintenance Disorders / Q000517:prevention & control*; D014851:Wakefulness