title: Continuous positive airway pressure improves sleepiness but not calculated vascular risk in patients with minimally symptomatic obstructive sleep apnoea: the MOSAIC randomised controlled trial.
abstract: BACKGROUND
  Continuous positive airway pressure (CPAP) for symptomatic obstructive sleep apnoea (OSA) improves sleepiness and reduces vascular risk, but such treatment for the more prevalent, minimally symptomatic disease is contentious.
  
  
  METHODS
  This multicentre, randomised controlled, parallel, hospital-based trial across the UK and Canada, recruited 391 patients with confirmed OSA (oxygen desaturation index >7.5/h) but insufficient symptoms to warrant CPAP therapy. Patients were randomised to 6 months of auto-adjusting CPAP therapy, or standard care. Coprimary endpoints were change in Epworth Sleepiness Score (ESS) and predicted 5-year mortality using a cardiovascular risk score (components: age, sex, height, systolic blood pressure, smoking, diabetes, cholesterol, creatinine, left ventricular hypertrophy, previous myocardial infarction or stroke). Secondary endpoints included some of the individual components of the vascular risk score, objectively measured sleepiness and self-assessed health status.
  
  
  RESULTS
  Of 391 patients randomised, 14 withdrew, 347 attended for their follow-up visit at 6 months within the predefined time window, of which 341 had complete ESS data (baseline mean 8.0, SD 4.3) and 310 had complete risk score data. 22% of patients in the CPAP group reported stopping treatment and overall median CPAP use was 2 : 39 h per night. CPAP significantly improved subjective daytime sleepiness (adjusted treatment effect on ESS -2.0 (95% CI -2.6 to -1.4), p<0.0001), objectively measured sleepiness and self-assessed health status. CPAP did not improve the 5-year calculated vascular risk or any of its components.
  
  
  CONCLUSIONS
  In patients with minimally symptomatic OSA, CPAP can reduce subjective and objective daytime sleepiness, and improve self-assessed health status, but does not appear to improve calculated vascular risk.
authors.affiliation: Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK. sonya.craig@orh.nhs.uk
authors.forename: Sonya Elizabeth
authors.initials: SE
authors.lastname: Craig
authors.forename: Malcolm
authors.initials: M
authors.lastname: Kohler
authors.forename: Debby
authors.initials: D
authors.lastname: Nicoll
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Bratton
authors.forename: Andrew
authors.initials: A
authors.lastname: Nunn
authors.forename: Robert
authors.initials: R
authors.lastname: Davies
authors.forename: John
authors.initials: J
authors.lastname: Stradling
mesh_terms: D002170:Canada / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control; D045422:Continuous Positive Airway Pressure; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000628:therapy*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology