Effects of Respiratory Muscle Therapy on Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

STUDY OBJECTIVES: The purpose of this study is to conduct a systematic review and meta-analysis evaluating the effects of respiratory muscle therapy (i.e. oropharyngeal exercises, speech therapy, breathing exercises, wind musical instruments) compared to control therapy or no treatment in improving Apnea-Hypopnea Index [AHI] (primary outcome), sleepiness and other polysomnographic outcomes for patients diagnosed with obstructive sleep apnea (OSA). METHODS: Only randomized controlled trials with a placebo therapy or no treatment searched using PubMed, EMBASE, Cochrane and Web of Science up to November 2018 were included and assessment of risk of bias was completed using the Cochrane handbook. RESULTS: Nine studies with 394 adults and children diagnosed with mild to severe OSA were included, all assessed at high risk of bias. Eight out of the nine studies measured AHI and showed a weighted average overall AHI improvement of 39.5% vs baselines after respiratory muscle therapy. Based on our meta-analyses in adult studies, respiratory muscle therapy yielded an improvement in AHI of -7.6 events/hr (95% Confidence Interval [CI]=-11.7 to -3.5; p