Although obstructive sleep apnea (OSA) is associated with impaired glucose tolerance and diabetes, it remains unclear whether OSA treatment with continuous positive airway pressure (CPAP) has metabolic benefits. The objective of this study is to determine the effect of 8-hour nightly CPAP treatment on glucose metabolism in individuals with prediabetes and OSA.

Although obstructive sleep apnea (OSA) is associated with impaired glucose tolerance and diabetes, it remains unclear whether OSA treatment with continuous positive airway pressure (CPAP) has metabolic benefits. To determine the effect of 8-hour nightly CPAP treatment on glucose metabolism in individuals with prediabetes and OSA. In a randomized, controlled parallel group study, 39 participants were randomized (2:1) to receive either 8-hour nightly CPAP (n=26) or oral placebo (n=13). Sleep was polysomnographically recorded in the laboratory on each night. CPAP adherence was ensured by continuous supervision. Participants continued their daily daytime routine activities outside the laboratory. Glucose metabolism was assessed at baseline and after 2-weeks of assigned treatment using both the oral and intravenous glucose tolerance tests (OGTT and ivGTT, respectively). The primary outcome was the overall glucose response as quantified by the area under the curve for glucose during 2-hour oral glucose tolerance testing.

Inclusion Criteria:

• Overweight or obese adults (age ≥45 yrs and BMI ≥25 kg/m2)
• prediabetes and OSA (AHI ≥ 5)
• regular life styles and schedules (no shift work in the past 6 months, no travel across time zones during the past 4 weeks)
• habitual bedtimes of at least 6 hours but not exceeding 9 hours will be eligible.
• not to take any medications during the study period with the exception of antihypertensives and lipid lowering agents
• not on hormone replacement therapy.
• have sedentary activities and no competitive athletes or subjects with high exercise levels.

Exclusion Criteria:

• previous or current treatment with supplemental oxygen
• requirement of supplemental oxygen or bi-level positive airway pressure for OSA treatment during titration
• presence of active infection, psychiatric disease or history of other significant illness (e.g., myocardial infarction, congestive heart failure, stroke, arrhythmia, chronic kidney or liver disease0
• clinical depression as evidenced by a score >16 in CES-D scale
• smoking, or routine alcohol use (more than 2 drinks per day), or excessive caffeine intake (>300mg per day)

2 weeks

Only treatment related adverse events were collected.