The purpose of this study is to determine whether functional status improves in individuals with milder obstructive sleep apnea (OSA) following continuous positive airway pressure (CPAP) treatment.
BACKGROUND: OSA is characterized as mild, moderate, or severe, according to the number of respiratory disturbances per hour of sleep (RDI), as defined by the American Academy of Sleep Medicine. CPAP is the primary treatment for sleep apnea. The column of pressure delivered to the upper airway by this device immediately eliminates the respiratory disturbances when it is applied. There is evidence from randomized controlled studies that CPAP also improves functional status, and the key manifestation of OSA, including excessive daytime sleepiness, in individuals with severe OSI (i.e., RDI greater than 30). However, there has been limited research exploring improvement in functional status in individuals with less severe OSA (i.e., those with mild OSA and RDI of 5-15 or moderate OSA and RDI of 16-30). The large placebo effect that has been reported in controlled studies of OSA-associated functional outcomes mandates the need for a placebo in studies evaluating the true impact of this treatment. Results from the three randomized controlled studies in milder OSA that have examined this issue have been equivocal, principally because of serious methodological limitations. It remains unclear whether CPAP treatment improves daily functioning in those with milder OSA (RDI 5-30). This is a critical issue as this level of disease severity represents the largest segment of OSA and comprises 15% of the U.S. population. DESIGN NARRATIVE: Using Granger's model of functional assessment, this study will examine whether functional status improves in participants with milder OSA following CPAP treatment. The study will employ a randomized, placebo-controlled, parallel study design, and will use a sham CPAP device as the placebo in participants with significant daytime sleepiness. The study will test the hypothesis that the change in functional status (measured by the Functional Outcomes of Sleep Questionnaire) after 8 weeks of treatment will be greater for participants treated with active CPAP compared to the placebo. Secondary aims of the study include examining whether CPAP also improves daytime sleepiness, and determining whether CPAP can reduce nocturnal blood pressure to lower the risk for stroke and hypertension linked to OSA.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
281
CPAP device used at night
Sham CPAP device used at night
National Jewish Medical and Research Center (NJC)
Denver, Colorado, United States
Emory University School of Medicine (EMO)
Atlanta, Georgia, United States
North Shore-Long Island Jewish Health System (LIJ)
Long Island City, New York, United States
New York University Medical School
New York, New York, United States
Change in the Score of the Functional Outcomes of Sleep Questionnaire at Baseline and Week 8 Treatment
The primary endpoint is change after 8 weeks of treatment from baseline value (controlling for baseline value) in the 30-item Functional Outcomes of Sleep Questionnaire (FOSQ) that will be used to test the primary study hypothesis that patients with milder OSA (RDI 5-30) on active treatment will demonstrate greater mean change for the Total score from baseline to 8 weeks treatment. The FOSQ is designed to assess the impact of excessive sleepiness on functional status. The instrument has established content validity, test-retest reliability (r= 0.91), and internal consistency (alpha = 0.96). The scale ranges from 5 - 20 with normal functional status being a value greater than 17.
Time frame: 8 weeks
Change in the Score From Baseline to 8 Weeks Treatment Epworth Sleepiness Scale
Change in the score from baseline to 8 weeks treatment, controlling for baseline in the self-rated 8 item measure of daytime sleepiness with a range from 0 - 24. Lower values indicting less daytime sleepiness
Time frame: Measured at Baseline and Week 8 of treatment in ITT sample
Change in Mean Arterial Daytime Pressure at Baseline and Week 8 Treatment
Change in mean arterial pressure (MAP) value from baseline to 8 weeks treatment, controlling for baseline, measured by 48 hours ambulatory blood pressure device - Space Laboratories
Time frame: Measured at Baseline and Week 8 treatment in the ITT sample
Change in the Score From Baseline to 8 Weeks Treatment Measured by the Profile of Mood States
Change in the score from baseline to 8 weeks treatment, controlling for baseline, in the POMS is a reliable and valid measure of mood states that consists of 65 adjectives on which subjects' rate themselves as they feel "today" using a five-point scale. There are six mood or affective states on this test derived through factor analysis: Tension-Anxiety (score range 0-36), Depression-Dejection (score range 0 - 60), Anger-Hostility (score range 0-48), Vigor-Activity (score range 0-32), Fatigue-Inertia (score range 0-28), and Confusion-Bewilderment (score range 0-28). There is also a summary Total Mood Disturbance (TMD) score that gives a Total estimate of affective state score range 0-200). Higher scores indicate greater disability.
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University of Western Ontario (UWO)
London, Ontario, Canada
Time frame: Measured at Baseline and Week 8 treatment in the ITT sample
Change in the Number of Lapses From Baseline to 8 Weeks Treatment on the Psychomotor Vigilance Task (PVT) - Total Lapses in 20 Minute Test
Change in the score from baseline to 8 weeks treatment, controlling for baseline, in the PVT is an objective assessment of sleepiness and measures decrements in neurobehavioral performance due to sleepiness, i.e., ability to sustain attention and respond in a timely manner to salient signals.(7) The PVT yields five highly informative metrics on the capacity for sustained attention and vigilance performance: frequency of lapses, duration of lapse domain, optimum response time, vigilance decrement function, false response frequency. We applied this conceptually valid, relatively short duration, reliable task with known psychometric properties and minimal practice/learning curves to document attentional lapses (response times \> 500 msec) in performance.
Time frame: Baseline and 8 weeks of treatment in the ITT sample
Change in the Score From Baseline to 8 Weeks Treatment on the SF36 - Physical
Change in the score from baseline to 8 weeks treatment, controlling for baseline, in the SF-36 is a 36-item questionnaire that assesses eight health concepts: physical functioning, bodily pain, role limitations due to physical problems, role limitations due to personal or emotional problems, emotional well-being, social functioning, energy/fatigue, and general health perceptions. Higher scores indicate greater disability with a range of scores from 0-100.
Time frame: Baseline and Week 8 of treatment in ITT sample.
Change in the Score From Baseline to 8 Weeks Treatment SF-36 Mental Component
Change in the score from baseline to 8 weeks treatment, controlling for baseline, in the SF-36 is a 36-item questionnaire that assesses eight health concepts: physical functioning, bodily pain, role limitations due to physical problems, role limitations due to personal or emotional problems, emotional well-being, social functioning, energy/fatigue, and general health perceptions. Higher scores indicate greater disability with a range of scores from 0-100.
Time frame: Baseline and after 8 weeks of treatment in ITT sample