Obstructive sleep apnea during the chronic stroke recovery period: Comparison between primary haemorrhagic and ischaemic events

The present study retrospectively determined the incidence of obstructive sleep apnea (OSA) after a primary haemorrhagic event compared to an ischaemic stroke during the post-acute recovery period ( $\overline{x}$ > 3 months). Consideration of medications taken during the sleep evaluation provided additional information on the association between OSA and pathophysiological conditions that may increase the risk of a repeated cardiovascular event. The medical records from 103 patients that underwent a type I fully attended overnight polysomnography as a standard evaluation procedure at a rehabilitation facility were reviewed. Diagnosis of ischaemic or primary haemorrhagic stroke was obtained from a neurological report that was typically confirmed by imaging. Medications taken at the time of the sleep study were documented. Age-adjusted assessment of sleep-disordered breathing revealed a higher incidence of apnea and hypopnea in the ischaemic stroke group (p < 0.005). Patients with ischaemic stroke were also more likely to have severe OSA (p < 0.005). In comparison, a higher percentage of patients with haemorrhagic stroke had an apnea-hypopnea index <5 events/hr (p < 0.005). Those with an ischaemic stroke were taking more lipid lowering agents (p < 0.05). Results suggest that apnea is less prevalent after a haemorrhagic stroke, independent of hypertension, compared to an ischaemic stroke. An increase in predictive values for OSA was observed for indicators of diabetes (p < 0.05). These data indicate that it is relevant to consider stroke type when determining the risk of OSA during the chronic recovery period thus facilitating new strategies for stroke recurrence prevention.