ArticlesComparison of therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised prospective parallel trial
Section snippets
Background
Nasal continuous positive airway pressure (NCPAP) is widely used as a treatment for obstructive sleep apnoea. However, to date there are no randomised controlled trials of this therapy against a well-matched control. We undertook a randomised prospective parallel trial of therapeutic NCPAP for obstructive sleep apnoea compared with a control group on subtherapeutic NCPAP.
Methods
Men with obstructive sleep apnoea, defined as an Epworth sleepiness score of 10 or more and ten or more dips per h of more
Patients
The Oxford Sleep Unit takes patients referred with possible obstructive sleep apnoea from the South Midlands, UK: a third of patients are from the Oxford area. Referrals are made by general practitioners (36%), ear, nose, and throat surgeons (41%), or other hospital consultants (23%). Patients were eligible for our trial if they had excessive daytime sleepiness, sleep apnoea, and were men aged between 30 and 75 years. Excessive daytime sleepiness was defined as an Epworth sleepiness score of 10
Results
During the recruitment period (January, 1997, to August, 1998) 172 patients were eligible for the study (figure 1). 65 people were excluded: 34 refused, mostly because of the longer study time or long-distance travel. Seven were judged too mentally impaired to give informed consent (three with major psychoses, two with severe learning difficulties, two with alcohol dependence), 14 chose alternative therapies or believed that their symptoms did not warrant such an intrusive therapy; eight needed
Discussion
Therapeutic NCPAP has a clear advantage over subtherapeutic NCPAP. Compared with a control, the main symptom of obstructive sleep apnoea (sleepiness) was significantly improved by therapeutic NCPAP, both objectively and subjectively. Therapeutic NCPAP improved Epworth scores by 7 points (95% CI 5–9), and for 73% of the therapeutic NCPAP group Epworth scores returned to within the normal range (number needed to treat=1·4), compared with only 29% of the subtherapeutic control group. These
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