title: A controlled trial of CPAP therapy on metabolic control in individuals with impaired glucose tolerance and sleep apnea.
abstract: OBJECTIVE
  To address whether treatment of sleep apnea improves glucose tolerance.
  
  
  METHODS
  Randomized, double-blind crossover study.
  
  
  METHODS
  Sleep clinic referrals.
  
  
  METHODS
  50 subjects with moderate to severe sleep apnea (AHI > 15) and impaired glucose tolerance.
  
  
  METHODS
  Subjects were randomized to 8 weeks of CPAP or sham CPAP, followed by the alternate therapy after a one-month washout. After each treatment, subjects underwent 2-hour OGTT, polysomnography, actigraphy, and measurements of indices of glucose control.
  
  
  RESULTS
  The primary outcome was normalization of the mean 2-h OGTT; a secondary outcome was improvement in the Insulin Sensitivity Index (ISI (0,120). Subjects were 42% men, mean age of 54 (10), BMI of 39 (8), and AHI of 44 (27). Baseline fasting glucose was 104 (12), and mean 2-h OGTT was 110 (57) mg/dL. Seven subjects normalized their mean 2-h OGTT after CPAP but not after sham CPAP, while 5 subjects normalized after sham CPAP but not after CPAP. Overall, there was no improvement in ISI (0,120) between CPAP and sham CPAP (3.6%; 95% CI: [-2.2%, 9.7%]; P = 0.22). However, in those subjects with baseline AHI ≥ 30 (n = 25), there was a 13.3% (95% CI: [5.2%, 22.1%]; P < 0.001) improvement in ISI (0,120) and a 28.7% (95%CI: [-46.5%, -10.9%], P = 0.002) reduction in the 2-h insulin level after CPAP compared to sham CPAP.
  
  
  CONCLUSIONS
  This study did not show that IGT normalizes after CPAP in subjects with moderate sleep apnea and obesity. However, insulin sensitivity improved in those with AHI ≥ 30, suggesting beneficial metabolic effects of CPAP in severe sleep apnea. Clinical trials information: ClinicalTrials.gov Identifier: NCT01385995.
authors.affiliation: Department of Medicine, Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
authors.forename: Tanya G
authors.initials: TG
authors.lastname: Weinstock
authors.forename: Xuelei
authors.initials: X
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: Rueschman
authors.forename: Faramarz
authors.initials: F
authors.lastname: Ismail-Beigi
authors.forename: Joan
authors.initials: J
authors.lastname: Aylor
authors.forename: Denise C
authors.initials: DC
authors.lastname: Babineau
authors.forename: Reena
authors.initials: R
authors.lastname: Mehra
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
mesh_terms: D056044:Actigraphy; D001786:Blood Glucose / Q000032:analysis; D045422:Continuous Positive Airway Pressure; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D018149:Glucose Intolerance / Q000150:complications / Q000378:metabolism / Q000628:therapy*; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000378:metabolism / Q000628:therapy*
chemical_list: D001786:Blood Glucose