Dissociation of obstructive sleep apnea from hypersomnolence and obesity in patients with stroke.

BACKGROUND AND
PURPOSE: Obstructive sleep apnea (OSA) is seldom considered in the diagnostic investigation in the poststroke period although it is a stroke risk factor and has adverse prognostic implications after stroke. One reason might be that widely used clinical criteria for detection of OSA in the general community are not applicable in patients with stroke. We hypothesized that patients with stroke report less sleepiness and are less obese than subjects from a community sample with the same severity of OSA.
METHODS: We performed polysomnography in 96 consecutive patients with stroke admitted to a stroke rehabilitation unit and in a community sample of 1093 subjects without a history of stroke. We compared the degrees of subjective sleepiness assessed by the Epworth Sleepiness Scale and body mass index between the 2 samples according to OSA categories assessed by the frequency of apneas and hypopneas per hour of sleep (<5, no OSA; 5 to <15 mild OSA; and >or=15, moderate to severe OSA).
RESULTS: Compared with the community sample, patients with stroke with OSA had significantly lower Epworth Sleepiness Scale scores and body mass index for mild OSA (Epworth Sleepiness Scale 9.3+/-0.3 versus 5.6+/-0.5, P<0.001 and body mass index 33.1+/-0.5 versus 28.5+/-1.1, P<0.048) and for moderate to severe OSA (Epworth Sleepiness Scale 9.7+/-0.4 versus 7.1+/-0.9, P=0.043 and body mass index 36.4+/-0.8 versus 27.2+/-0.8 kg/m(2), P<0.025).
CONCLUSIONS: For a given severity of OSA, patients with stroke had less daytime sleepiness and lower body mass index than subjects without stroke. These factors may make the diagnosis of OSA elusive in the poststroke period and preclude many such patients from the potential benefits of OSA therapy.