The investigators performed a randomized, cross-over controlled clinical trial comparing 8 weeks of Continuous Positive Airway Pressure (CPAP) to 8 weeks of sham-CPAP in patients with moderate to severe Sleep Disordered Breathing (SDB) and impaired glucose tolerance. A rigorous assessment of metabolic responses to SDB treatment in this group is of great clinical significance because this sample is at high risk for developing diabetes. The paradigm shift of CPAP as a mode of prevention can affect clinical practice in the fields of both primary care and sleep medicine.
There are few controlled studies that address whether treatment of sleep apnea improves glucose tolerance. This is a randomized, double-blind cross-over study of subjects with sleep apnea (apnea hypopnea index \> 15) and impaired glucose tolerance. Subjects will be randomized to 8 weeks of Continuous Positive Airway Pressure (CPAP) or sham-CPAP, followed by the alternate therapy after a one month wash-out. After each treatment, subjects will undergo 2-hour oral glucose tolerance testing, polysomnography, actigraphy, and measurements of indices of glucose control. The investigators intend to analyze the changes in glucose metabolism and insulin sensitivity in patients with sleep apnea with CPAP intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
50
Subjects will be randomized to 8 weeks of CPAP or sham-CPAP, followed by the alternate therapy after a one month wash-out.
Subjects will be randomized to 8 weeks of CPAP or sham-CPAP, followed by the alternate therapy after a one month wash-out.
Number of Subjects With Normalization of Impaired Glucose Tolerance (IGT)
Number of subjects who experienced normalization of the mean 2-hour oral glucose tolerance test (OGTT) in the overall sample undergoing therapeutic CPAP vs. sham CPAP. (2-hour OGTT glucose\< 140 mg/dL)
Time frame: 20 weeks
Mean and Standard Deviation of Glucose Indices After Therapeutic CPAP vs. Sham
Reported values include: fasting glucose (mg/dL), 2 hour Oral Glucose Tolerance Test (OGTT) (mg/dL)
Time frame: 20 weeks
Mean and Standard Deviation of Insulin Indices After Therapeutic CPAP vs. Sham
The data for fasting and 2 hour Insulin (iIU/dL) are presented according to therapeutic CPAP vs. Sham CPAP.
Time frame: 20 weeks
Mean and Standard Deviation of Indices of Insulin Resistance With Therapeutic CPAP vs. Sham
Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) with therapeutic CPAP vs. Sham CPAP
Time frame: 20 weeks
Mean and Standard Deviation of Insulin Sensitivity Index (ISI(0,120)) With Therapeutic CPAP vs. Sham
Insulin Sensitivity Index derived from the Gutt Index, uses the plasma glucose and insulin concentration from fasting (0 min) and 120-min samples from the OGTT, to calculate (Metabolic Clearance Rate)/log (Mean Serum Insulin). The range of possible values is based on the subset ranges of fasting and oral glucose tolerance test (OGTT) insulin and fasting and OGTT glucose, which calculate to be a range of 1.6 to 206.8. An increase in the ISI (0,120) indicates an improvement in the insulin sensitivity.
Time frame: 20 Weeks
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