A Cochrane review [Abstract] 1 included 36 studies with a total of 1 718 subjects. Study quality was mixed. Compared with control, CPAP showed significant improvements in certain objective and subjective measures of sleepiness, quality of life and cognitive function (parallel-group studies: Epworth sleepiness scale (ESS) -3.83 units, 95% CI -4.57 to -3.09; crossover studies: ESS -1.84 units, 95% CI -2.57 to -1.11). Twenty-four hour systolic and diastolic blood pressures were lower with CPAP compared with control (parallel-group trials). Compared with oral appliances, CPAP significantly reduced the apnoea and hypopnoea index (crossover studies: -7.97 events/hr, 95% CI -9.56 to -6.38) and improved sleep efficiency (crossover studies: 2.31%, 95% CI 0.02 to 4.6) and minimum oxygen saturation (4.14%, 95% CI 3.25 to 5.03). Responders to both treatments expressed a strong preference for the oral appliance. However, participants were more likely to withdraw on OA than on CPAP therapy.
In a meta-analysis of randomized trials 2, three trials with a total of 71 patients comparing positional therapy versus CPAP in patients with positional OSA (obstructive sleep apnea) were included. Apnea-hypopnea index (AHI), mean oxygen saturation level, arousal index, sleep efficiency, and sleep time were the outcomes of this meta-analysis. Positional therapy showed higher AHI (MD 4.28, 95% CI 0.72 to 7.83) and lower oxygen saturation level (MD -1.04, 95% CI -1.63 to -0.46) than CPAP. It showed no distinct advantage over CPAP in terms of arousal index, sleep efficiency, and total sleep time, but CPAP reduced sleep time in the supine position.
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