title: Is obstructive sleep apnea an independent risk factor for stroke? A critically appraised topic.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is associated with hypertension, atrial fibrillation, coronary artery disease, congestive heart failure, and diabetes. These disorders are also risk factors for stroke.
  
  
  OBJECTIVE
  To determine whether OSA increases the risk of stroke independently of other cerebrovascular risk factors.
  
  
  METHODS
  The objective was addressed through the development of a structured critically appraised topic. This evidence-based methodology included a clinical scenario, structured question, search strategy, critical appraisal, results, evidence summary, commentary, and bottom line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and content experts in the field of sleep medicine and vascular neurology.
  
  
  RESULTS
  A large observational cohort study was selected and appraised to address this prognostic question. The unadjusted analysis revealed that OSA (apnea-hypopnea index >5) was associated with stroke or death from any cause (hazard ratio, 2.24; 95% confidence interval [CI], 1.30-3.86; P = 0.004). The adjusted OSA analysis retained a statistically significant association with stroke or death (hazard ratio, 1.97; 95% CI, 1.12-3.48; P = 0.01). In separate unadjusted analyses, OSA was associated with death and stroke with relative risks of 1.68 (95% CI, 1.10-2.25) and 5.16 (95% CI, 3.72-6.60), respectively.
  
  
  CONCLUSIONS
  OSA independently contributes to stroke risk.
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, AZ, USA.
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Capampangan
authors.forename: Kay E
authors.initials: KE
authors.lastname: Wellik
authors.forename: James M
authors.initials: JM
authors.lastname: Parish
authors.forename: Maria I
authors.initials: MI
authors.lastname: Aguilar
authors.forename: Charlene R Hoffman
authors.initials: CR
authors.lastname: Snyder
authors.forename: Dean
authors.initials: D
authors.lastname: Wingerchuk
authors.forename: Bart M
authors.initials: BM
authors.lastname: Demaerschalk
mesh_terms: D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure; D006801:Humans; D016239:MEDLINE; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D020521:Stroke / Q000209:etiology* / Q000503:physiopathology; D016896:Treatment Outcome