Oral Appliance Versus Continuous Positive Airway Pressure in Obstructive Sleep Apnea Syndrome: A 2-Year Follow-up

STUDY OBJECTIVES: Oral appliance therapy has emerged as an important alternative to continuous positive airway pressure (CPAP) in treating patients with obstructive sleep apnea syndrome (OSAS). In this study we report about the subjective and objective treatment outcome of oral appliance therapy and CPAP in patients with OSAS. DESIGN: Cohort study of a previously conducted randomized clinical trial. SETTING: University Medical Center, Groningen, The Netherlands. PATIENTS OR PARTICIPANTS: One hundred three patients with OSAS. INTERVENTIONS: CPAP and oral appliance therapy (Thornton Adjustable Positioner type-1, Airway Management, Inc., Dallas, TX, USA). MEASUREMENTS AND RESULTS: Objective (polysomnography) and subjective (Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, Medical Outcomes Study 36-item Short Form Health Survey [SF-36]) parameters were assessed after 1 and 2 years of treatment. Treatment was considered successful when the apnea-hypopnea index (AHI) was < 5 or showed substantial reduction, defined as reduction in the index of at least 50% from the baseline value to a value of < 20 in a patient without OSAS symptoms while undergoing therapy. Regarding the proportions of successful treatments, no significant difference was found between oral appliance therapy and CPAP in treating mild to severe OSAS in a 2-year follow-up. More patients (not significant) dropped out under oral appliance therapy (47%) compared with CPAP (33%). Both therapies showed substantial improvements in polysomnographic and neurobehavioral outcomes. However, CPAP was more effective in lowering the AHI and showed higher oxyhemoglobin saturation levels compared to oral appliance therapy (P < 0.05). CONCLUSIONS: Oral appliance therapy should be considered as a viable treatment alternative to continuous positive airway pressure (CPAP) in patients with mild to moderate obstructive sleep apnea syndrome (OSAS). In patients with severe OSAS, CPAP remains the treatment of first choice. CLINICAL TRIAL INFORMATION: The original randomized clinical trial, of which this study is a 2-year follow-up, is registered at ISRCTN.org; identifier: ISRCTN18174167; trial name: Management of the obstructive sleep apnea-hypopnea syndrome: oral appliance versus continuous positive airway pressure therapy; URL: http://www.controlled-trials.com/ISRCTN18174167.