Continuous positive airway pressure (CPAP) therapy has been regarded for more than a decade by those in the field as the treatment of choice for the sleep apnoea/hypopnoea syndrome (SAHS). Nevertheless, two recent systematic reviews1 ,2 have appropriately pointed out that there is a shortage of robust evidence that CPAP benefits medium and long term outcomes in SAHS. However, the striking aspect of the two reviews is their diametrically opposed conclusions about the efficacy of CPAP, one concluding from the evidence that CPAP was indicated in patients with more than 20 apnoeas + hypopnoeas per hour of sleep plus daytime sleepiness,1 whereas the other concluded that “the studies do not provide sufficiently robust evidence for the effectiveness of CPAP”.2 There are differences in the design of these reviews which may account for this disparity.

Systematic review should be impartial. The review by Wright and colleagues3 was funded, at least in the initial stages, by purchasing authorities concerned about the increasing costs of provision of sleep services and CPAP. Sackett has commented that there is a “fear that evidence based medicine may be hijacked by purchasers and managers to cut the costs of healthcare”.4 The study by Wright et al 2 would appear to be one such example. In contrast, the Australasian study1 was commissioned by the Australian Medical Research Council and the New Zealand Ministry of Health.

Evidence based medicine has been defined as “integrating individual clinical expertise with the best available external clinical evidence from systematic research”, where clinical expertise is “the proficiency and judgement that individual clinicians acquire through clinical experience and clinical practice”.4 Wright and colleagues2 did not …