title: CPAP versus oxygen in obstructive sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea is associated with hypertension, inflammation, and increased cardiovascular risk. Continuous positive airway pressure (CPAP) reduces blood pressure, but adherence is often suboptimal, and the benefit beyond management of conventional risk factors is uncertain. Since intermittent hypoxemia may underlie cardiovascular sequelae of sleep apnea, we evaluated the effects of nocturnal supplemental oxygen and CPAP on markers of cardiovascular risk.
  
  
  METHODS
  We conducted a randomized, controlled trial in which patients with cardiovascular disease or multiple cardiovascular risk factors were recruited from cardiology practices. Patients were screened for obstructive sleep apnea with the use of the Berlin questionnaire, and home sleep testing was used to establish the diagnosis. Participants with an apnea-hypopnea index of 15 to 50 events per hour were randomly assigned to receive education on sleep hygiene and healthy lifestyle alone (the control group) or, in addition to education, either CPAP or nocturnal supplemental oxygen. Cardiovascular risk was assessed at baseline and after 12 weeks of the study treatment. The primary outcome was 24-hour mean arterial pressure.
  
  
  RESULTS
  Of 318 patients who underwent randomization, 281 (88%) could be evaluated for ambulatory blood pressure at both baseline and follow-up. On average, the 24-hour mean arterial pressure at 12 weeks was lower in the group receiving CPAP than in the control group (-2.4 mm Hg; 95% confidence interval [CI], -4.7 to -0.1; P=0.04) or the group receiving supplemental oxygen (-2.8 mm Hg; 95% CI, -5.1 to -0.5; P=0.02). There was no significant difference in the 24-hour mean arterial pressure between the control group and the group receiving oxygen. A sensitivity analysis performed with the use of multiple imputation approaches to assess the effect of missing data did not change the results of the primary analysis.
  
  
  CONCLUSIONS
  In patients with cardiovascular disease or multiple cardiovascular risk factors, the treatment of obstructive sleep apnea with CPAP, but not nocturnal supplemental oxygen, resulted in a significant reduction in blood pressure. (Funded by the National Heart, Lung, and Blood Institute and others; HeartBEAT ClinicalTrials.gov number, NCT01086800 .).
authors.affiliation: From the Veterans Affairs Boston Healthcare System (D.J.G., D.L.B.), Brigham and Women's Hospital (D.J.G., S.R.P., S.F.Q., M.R., E.F.L., D.L.B., S.R.), Harvard Medical School (D.J.G., S.R.P., S.F.Q., E.F.L., D.L.B., S.R.), Boston University School of Medicine (D.J.G.), and Beth Israel Deaconess Medical Center (S.R.P., S.R.) - all in Boston; Johns Hopkins University, Baltimore (N.M.P., R.S.B.); Cleveland Clinic (R.M.) and Case Western Reserve University (R.M., D.C.B.) - both in Cleveland; and the University of Vermont, Colchester (R.P.T.).
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gottlieb
authors.forename: Naresh M
authors.initials: NM
authors.lastname: Punjabi
authors.forename: Reena
authors.initials: R
authors.lastname: Mehra
authors.forename: Sanjay R
authors.initials: SR
authors.lastname: Patel
authors.forename: Stuart F
authors.initials: SF
authors.lastname: Quan
authors.forename: Denise C
authors.initials: DC
authors.lastname: Babineau
authors.forename: Russell P
authors.initials: RP
authors.lastname: Tracy
authors.forename: Michael
authors.initials: M
authors.lastname: Rueschman
authors.forename: Roger S
authors.initials: RS
authors.lastname: Blumenthal
authors.forename: Eldrin F
authors.initials: EF
authors.lastname: Lewis
authors.forename: Deepak L
authors.initials: DL
authors.lastname: Bhatt
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000150:complications*; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D012307:Risk Factors; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology / Q000628:therapy*