Objectives: The onset of ischemic stroke symptoms has been established to have a diurnal variation, with a sizeable proportion (8-28%) occurring during sleep. Obstructive sleep apnea (OSA) has been established as an important risk factor for ischemic stroke. However, data on the relationship between OSA and wake-up stroke (WUS) has been scarce. The aim of our study is to determine the relationship between OSA and WUS.
Methods: This is a case-control study conducted on acute stroke patients who presented to one of two major medical centers in Riyadh of Saudi Arabia. Those who woke up with the symptoms were labeled as WUS, and those whose stroke occurred while awake were labeled as non wake-up stroke (NWUS). The Berlin Questionnaire, which was submitted to either the patient or his/her partner, was used to determine the frequency of OSA in the two groups.
Results: One hundred seven patients (60% males) with acute stroke were admitted between March 2016 and March 2017. Of the 40 patients with WUS, 29 (72.5%) had underlying OSA based on the Berlin Questionnaire, whereas only 30 (45%) of the 67 patients with NWUS have underlying OSA. Logistic regression analysis showed OSA is highly prevalent in the patients with WUS (OR = 3.25; 95% CI = 1.397-8.38; p = 0.0053).
Conclusion: OSA is an important risk factor for ischemic stroke during sleep. Health care providers must be vigilant in inquiring about symptoms suggestive of OSA in every ischemic stroke patient, especially the patient whose stroke occurred during sleep.
Keywords: Berlin Questionnaire; Obstructive sleep apnea; Stroke; Wake-up.