Objective: To examine the research evidence for
the
health consequences of obstructive sleep apnoea and the effectiveness
of continuous positive airways pressure.
Design: A systematic review of published research,
studies being identified by searching Medline (1966-96), Embase
(1974-96), and CINAHL (Cumulative Index to Nursing and Allied Health
Literature) (1982-95); scanning citations; and consulting experts.
Studies in all languages were considered which either investigated the
association between obstructive sleep apnoea in adults and key health
outcomes or evaluated the effectiveness of treatment of obstructive
sleep apnoea with continuous positive airways pressure in adults.
Main outcome measures: Mortality, systematic
hypertension, cardiac arrhythmias, ischaemic heart disease, left
ventricular hypertrophy, pulmonary hypertension, stroke, vehicle
accidents, measures of daytime sleepiness, and quality of life.
Results: 54 epidemiological studies examined the
association between sleep apnoea and health related outcomes. Most were
poorly designed and only weak or contradictory evidence was found of an
association with cardiac arrhythmias, ischaemic heart disease, cardiac
failure, systemic or pulmonary hypertension, and stroke. Evidence of a
link with sleepiness and road traffic accidents was stronger but
inconclusive. Only one small randomised controlled trial evaluated
continuous positive airways pressure. Five non-randomised controlled
trials and 38 uncontrolled trials were identified. Small changes in
objectively measured daytime sleepiness were consistently found, but
improvements in morbidity, mortality, and quality of life indicators
were not adequately assessed.
Conclusions: The relevance of sleep apnoea to public
health has been exaggerated. The effectiveness of continuous positive
airways pressure in improving health outcomes has been poorly
evaluated. There is enough evidence suggesting benefit in reducing
daytime sleepiness in some patients to warrant large randomised placebo
controlled trials of continuous positive airways pressure versus an
effective weight reduction programme and other interventions.
Bradford Royal Infirmary,
Bradford,
West Yorkshire
BD9 6RJ
John Wright, consultant in
epidemiology and public health medicine
North Yorkshire Health
Authority,
York YO3 4XF
Rachel
Johns, research development
manager
NHS Centre for Reviews and Dissemination,
University of York,
York YOU DD
Ian
Watt, consultant in public health
medicine
Arabella Melville, research
fellow
Trevor
Sheldon, director
Correspondence to: Dr
Wright
(j.wright@leeds.ac.uk).
