A controlled trial of CPAP therapy on metabolic control in individuals with impaired glucose tolerance and sleep apnea.

Abstract

STUDY OBJECTIVES:

To address whether treatment of sleep apnea improves glucose tolerance.

DESIGN:

Randomized, double-blind crossover study.

SETTING:

Sleep clinic referrals.

PATIENTS:

50 subjects with moderate to severe sleep apnea (AHI > 15) and impaired glucose tolerance.

INTERVENTIONS:

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.

MEASUREMENTS AND 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: Tanya G Weinstock, Xuelei Wang, Michael Rueschman, Faramarz Ismail-Beigi, Joan Aylor, Denise C Babineau, Reena Mehra, Susan Redline
• Journal: Sleep (Sleep) Vol. 35 Issue 5 Pg. 617-625B (May 01 2012) ISSN: 1550-9109 [Electronic] United States
• PMID: 22547887 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, N.I.H., Extramural)

Chemical References

• Blood Glucose

Topics

• Actigraphy
• Blood Glucose (analysis)
• Continuous Positive Airway Pressure
• Cross-Over Studies
• Double-Blind Method
• Female
• Glucose Intolerance (complications, metabolism, therapy)
• Glucose Tolerance Test
• Humans
• Male
• Middle Aged
• Polysomnography
• Sleep Apnea Syndromes (complications, metabolism, therapy)