Oral appliance therapy for the management of obstructive sleep apnea in adults: an umbrella review.

Abstract

Objective: The aim of this umbrella review was to assess the effectiveness of oral appliance therapy compared to continuous positive airway pressure (CPAP), surgery, inactive appliances/controls, exercise, or other conservative techniques in mitigating symptoms among adults diagnosed with obstructive sleep apnea.

Introduction: Sleep-disordered breathing encompasses a spectrum of recurrent episodes of upper airway narrowing during sleep, marked by symptoms such as snoring, heightened upper airway resistance, or obstructive sleep apnea. The management of obstructive sleep apnea involves a range of conservative and surgical approaches. Among conservative methods, oral appliances are the preferred treatment for primary snoring, mild to moderate cases, and severe cases in patients who are intolerant to CPAP. While several systematic reviews have explored the effectiveness of oral appliance therapy for obstructive sleep apnea, there has been no comprehensive evaluation or synthesis of these reviews.

Inclusion criteria: Systematic reviews, with or without meta-analysis, were examined to assess the effectiveness of various forms of oral appliances in treating obstructive sleep apnea. Polysomnography was employed as the method for evaluating the effectiveness of the appliance. The primary outcome of interest was the effectiveness of oral appliance therapy in reducing the apnea-hypopnea index. Secondary outcomes included the mean change in the respiratory arousal index, Epworth Sleepiness Scale scores, minimum oxygen saturation, sleep efficiency, rapid eye movement sleep, blood pressure, quality of life, patient preference, and adverse effects.

Methods: A comprehensive search was conducted up to October 2023 in MEDLINE (Ovid), CINAHL (EBSCOhost), Scopus, Web of Science Core Collection, Epistemonikos, ProQuest Dissertations and Theses, Shodhganga, and the Cochrane Database of Systematic Reviews. Supplementary searches were manually performed using Google Scholar. The critical appraisal and data extraction processes were carried out independently by 2 reviewers. The extracted data were summarized using a tabular format accompanied by supporting text. The quality of evidence was evaluated utilizing the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results: This umbrella review incorporated 27 systematic reviews published between 2004 and 2022. The primary studies in these systematic reviews were published between 1996-2021. Of the 68 primary studies, 50 were published between 1996-2014 and 18 were published between 2015-2021. The corrected covered area index was 15.04%, indicating very high overlap between the primary studies included in the systematic reviews. All systematic reviews that compared oral appliances with CPAP consistently reported that CPAP was more efficacious, evidenced by a decrease in the apnea-hypopnea index, respiratory arousal index, and improved minimum oxygen saturation levels. However, patient preference favored oral appliance over CPAP. Additionally, oral appliances demonstrated improvements in subjective sleepiness scores and indices including the apnea-hypopnea index and respiratory arousal index when compared with inactive appliances/controls. The overall quality of evidence using GRADE ranged from very low to moderate.

Conclusions: CPAP has demonstrated greater efficacy than oral appliances in reducing the apnea-hypopnea index and respiratory arousal index while increasing minimum oxygen saturation levels, indicating significant improvements in obstructive sleep apnea and contributing to enhanced sleep quality and overall health. Despite these advantages, patient preference often leans toward oral appliances over CPAP. Compared with inactive appliances/controls, surgery, and other conservative management approaches, oral appliances have also shown efficacy in improving obstructive sleep apnea. This umbrella review reinforces CPAP as the gold standard for obstructive sleep apnea treatment, although oral appliances represent a viable alternative, particularly for patients who experience difficulties in accessing or tolerating CPAP. The majority of included systematic reviews were published over a decade ago, highlighting a research gap in this area. Therefore, future studies should focus on comparing newer treatment options for obstructive sleep apnea.