Effects of Treatment of Sleep Apnea on Metabolic Syndrome

A Controlled Trial of Continuous Positive Airway Pressure (CPAP) Therapy on Metabolic Control in Individuals With Impaired Glucose Tolerance and Sleep Apnea

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.

Inclusion Criteria:

• moderate to severe Sleep Disordered Breathing (SDB) defined by an Apnea Hypopnea Index (AHI) > 15
• had evidence of Impaired Glucose Tolerance (IGT) defined by the mean 2-hour Oral Glucose Tolerance Test (OGTT) glucose of > 140 mg/dl calculated from the two 2-hour OGTTs performed within 3 days of each other