Study designs of evaluations included in the review
The included study designs were randomised controlled trials (RCTs), non-randomised controlled trials, before-and-after studies, cohort and case-control studies. Only one RCT was identified and only 6 of the studies had control groups. Studies were only included if they reported clinical outcomes.
Specific interventions included in the review
Continuous positive airways pressure. One trial involved a comparison with uvulopalatopharyngoplasty, another with weight loss.
Participants included in the review
Patients aged over 16 years with obstructive sleep apnoea were included.
Outcomes assessed in the review
All reported clinical outcomes were extracted. The main outcomes extracted were sleepiness, mood, psychometric performance and blood-pressure. Compliance and withdrawal from treatment were also considered. Other outcomes mentioned were left ventricular ejection fraction, blood chemistry, driving ability, heart failure and nocturnal angina. Studies involving only acute or physiological changes during sleep or sleep apnoeas were not included.
How were decisions on the relevance of primary studies made?
Each paper was independently evaluated by two assessors, and any disagreements were resolved by consensus decision with a third assessor. Reasons for exclusion of studies were recorded.