Comparative Outcomes Management With Electronic Data Technology (COMET) Study

Inclusion Criteria:

   - Age > 18 years.

   - BMI > = 25.0 kg/m^2.

   - A diagnosis of obstructive sleep apnea based upon medical history and apnea- hypopnea
   index > = 10.0 or oxygen desaturation index (ODI; ≥4%) ≥ 10.0 on Diagnostic
   Polysomnogram.

   - Report a history of hypertension (or need for treatment for hypertension) which is
   currently untreated OR taking medication for the treatment of hypertension.

   - Stable medication regimen for 2 months prior to the Baseline Testing Visit. As-needed
   medications such as those used for allergy, cold, or minor pain symptoms may be used
   at the discretion of the Clinical Center physician.

Exclusion Criteria:

   - Cardiovascular disease which, in the judgment of the investigator, if observed during
   standard clinical practice would lead the treating physician to make every effort to
   treat the patient's sleep apnea with positive airway pressure, rather than alternative
   treatments.

   - Clinically significant acute or chronic disease that is not well controlled or could
   affect ability to complete or comply with study procedures, in the opinion of the
   Clinical Center physician.

   - Respiratory disease requiring supplemental oxygen or medication. Individuals with
   asthma may be included at the discretion of the Clinical Center physician if disease
   is well controlled and medications are stable for 2 months.

   - History of (within 12 months prior to enrollment), or current diagnosis of, Axis I or
   Axis II psychiatric disorder (other than obstructive sleep apnea) that in the opinion
   of the Clinical Center physician would affect ability to complete or comply with study
   procedures (e.g., schizophrenia and other psychotic disorders).

   - History of (within 3 months prior to enrollment), or current diagnosis of narcolepsy,
   idiopathic hypersomnia, restless legs syndrome, rapid eye movement (REM) behavior
   disorder, persistent situational insomnia, or sleep-related breathing disorders other
   than obstructive sleep apnea.

   - Periodic limb movement arousal index > 10.0 on the Diagnostic Polysomnogram.

   - Significant daytime sleepiness at study entry as indicated by:

      - an Epworth Sleepiness Scale total score > 16, or a score of 3 (high chance) on
      the question about risk of dozing "In a car, while stopped for a few minutes in
      traffic" or

      - a report of falling asleep at the wheel, a motor vehicle accident, or near-miss
      accident due to sleepiness in the past 24 months, which in the judgment of the
      study physician was not attributable to acute sleep loss.

   - Oxygen saturation < 80% for > 10% of sleep time during the Diagnostic Polysomnogram,
   or intervention with positive airway pressure or oxygen for safety purposes during the
   Diagnostic Polysomnogram.

   - Any prior treatment for obstructive sleep apnea with positive airway pressure or oral
   appliance, or surgical treatment for obstructive sleep apnea in the past year.

   - Contraindication for treatment with either positive airway pressure or oral appliance,
   in the opinion of the Clinical Center physician or dentist, including significant
   nasal obstruction, insufficient or loose teeth, dentures, advanced periodontal
   disease, or significant temporomandibular joint pain.

   - Pregnancy.

   - Difficulty understanding or speaking English, or inability to read and understand
   informed consent and study procedures.

   - Significant vision, hearing, or motor problems that, in the opinion of the Clinical
   Center physician, would affect ability to complete study procedures.

   - A work schedule that does not allow for nighttime sleep on the 3 nights before each
   study visit.

   - Current or planned participation in another research study.

   - Metal objects, devices, or implants that are in or on the body (Stanford Clinical
   Center only).

   - Creatinine clearance <30 and creatinine >1.6 (Stanford Clinical Center only).

   - Upper arm circumference > 20 inches