Wake‐up strokes are linked to obstructive sleep apnea and worse early functional outcome

Abstract

Background and AimsPresence of sleep‐disordered breathing (SDB) and especially obstructive sleep apnea (OSA) is a known risk factor for ischemic stroke. Additionally, SDB effects negatively on recovery after stroke. Up to one fourth of strokes are present on awakening. The link between OSA and wake‐up stroke (WUS) has been suggested. We aim to determine the association between OSA and WUS in a Finnish stroke unit cohort.Material and MethodsAn observational prospective longitudinal study consisted of 95 TIA (transient ischemic attack) and mild to moderate stroke patients referred to a Stroke Unit in Finland. Respiratory polygraphy was performed within 72 h of hospital admission. Patients were classified into WUS and non‐WUS, and functional outcome measures (mRS, rehabilitation, hospitalization time) were collected. Functional outcomes and prevalence of OSA were compared between non‐WUS and WUS.ResultsOSA (AHI > 15/h) was more frequent among WUS than non‐WUS (71% and 36%, respectively, p = 0.009). Functional outcome measured with mRS was worse in patients with WUS than non‐WUS on registration day and at hospital discharge (p = 0.001). Need for rehabilitation in WUS was 43% of cases compared to 23% of non‐WUS (p = 0.067). Hospitalization time was longer (5–15days) in 55% of WUS and 41% of non‐WUS patients (p = 0.261).ConclusionModerate‐to‐severe OSA is related to WUS compared to non‐WUS. In addition, WUS have worse short‐term outcomes measured in mRS. Further studies are needed to determine if OSA is causally linked to WUS.