Continuous positive airways pressure for obstructive sleep apnoea

Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is daytime sleepiness although there it has been linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents.

The main treatment for sleep apnoea is with continuous positive airways pressure (CPAP) treatment, which consists of a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults.

We searched the Cochrane Airways Group RCT register (MEDLINE 1966 to 2000, Embase 1974 to 2000, Cinahl 1982 to 2000) and the reference lists of articles. We consulted experts in the field.

Randomised trials comparing nocturnal CPAP with placebo or other treatments in adults with obstructive sleep apnoea and an apnoea/hypopnoea index greater than five per hour.

Trial quality was assessed and two reviewers extracted data independently. Study authors were contacted for missing information.

Twelve trials involving 475 people were included. Most studies had methodological shortcomings. Most trials were of crossover design. Compared with placebo, CPAP showed significant improvements in objective and subjective sleepiness and several quality of life and depression measures. Patients preferred CPAP to placebo (odds ratio 0.4, 95% confidence interval 0.2 to 0.8). There was no significant effect on daytime blood pressure. Compared with oral appliances, CPAP significantly improved the apnoea/hypopnoea index (weighted mean difference -7.3, 95% confidence interval -10.0 to -4.7) and minimum oxygen saturation during sleep. Patients strongly preferred the oral appliance to CPAP (odds ratio 9.5, 95% confidence interval 4.3 to 21.1).

CPAP is more effective than placebo in improving sleepiness and quality of life measures for people with obstructive sleep apnoea. It is more effective than oral appliances in improving respiratory disturbances. Although patients prefer CPAP to placebo, they preference oral appliances to CPAP.