• Alan T Mulgrew, Nurit Fox, Najib T Ayas, and C Frank Ryan.
• University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada.
• Ann. Intern. Med. 2007 Feb 6;146(3):157-66.

BackgroundPolysomnography (PSG), despite limited availability and high cost, is currently recommended for diagnosis of obstructive sleep apnea and titration of effective continuous positive airway pressure (CPAP).ObjectiveTo test the utility of a diagnostic algorithm in conjunction with ambulatory CPAP titration in initial management of obstructive sleep apnea.DesignA randomized, controlled, open-label trial that compared standard PSG with ambulatory CPAP titration in high-risk patients identified by a diagnostic algorithm.SettingA tertiary referral sleep disorders program in Vancouver, British Columbia, Canada.Patients68 patients with a high pretest probability of moderate to severe obstructive sleep apnea (apnea-hypopnea index [AHI] >15 episodes/h) identified by sequential application of the Epworth Sleepiness Scale (ESS) score, Sleep Apnea Clinical Score, and overnight oximetry.InterventionPatients were randomly assigned to PSG or ambulatory titration by using a combination of auto-CPAP and overnight oximetry. They were observed for 3 months.MeasurementsApnea-hypopnea index on CPAP, ESS score, quality of life, and CPAP adherence.ResultsThe PSG and ambulatory groups had similar median BMI (38 kg/m2), age (55 years), ESS score (14 points), and respiratory disturbance index (31 episodes of respiratory disturbance/h). Each episode is determined by a computer algorithm based on analysis of oxygen saturation measured by pulse oximetry. After 3 months, there were no differences in the primary outcome, AHI on CPAP (median, 3.2 vs. 2.5; difference, 0.8/h [95% CI, -0.9 to 2.3]) (P = 0.31), between the PSG and ambulatory groups, or in the secondary outcomes, ESS score, Sleep Apnea Quality of Life Index, and CPAP. Adherence to CPAP therapy was better in the ambulatory group than in the PSG group (median, 5.4 vs. 6.0; difference, -1.12 h/night [CI, -2.0 to 0.2]) (P = 0.021).ConclusionsIn the initial management of patients with a high probability of obstructive sleep apnea, PSG confers no advantage over the ambulatory approach in terms of diagnosis and CPAP titration. The ambulatory approach may improve adherence to treatment. When access to PSG is inadequate, the ambulatory approach can be used to expedite management of patients most in need of treatment.

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