Wake-up stroke: incidence, risk factors and outcome of acute stroke during sleep in a Japanese population. Takashima Stroke Registry 1988-2003.

Characterization of the time of stroke onset has been plagued by the problem of determining the time of the onset of events that are detected when the patient awakens. Our aim was to evaluate the characteristics, risk factors and acute fatality associated with wake-up stroke. Data was obtained from Takashima Stroke Registry covering approximately 55,000 residents in central Japan. During the period 1988-2003, information about the situation at stroke onset was available for 897 cerebral infarction (CI) and 335 intracerebral hemorrhage (ICH) events. Differences in characteristics and outcome between stroke during sleep and stroke while awake were explored. Among CI and ICH cases, 9.7 and 11.9% suffered from stroke during sleep, respectively. Hypertension and experiencing a severe event were associated with stroke during sleep among CI. Smoking and experiencing a severe event were associated with stroke during sleep and a drinking history reduced the chance of stroke during sleep among ICH. Acute fatality risks did not differ between stroke during sleep and stroke while awake among both CI and ICH cases. About 1 in 10 stroke patients had an onset of stroke during sleep. Hypertensive, smoker and clinically more severely affected patients had a higher prevalence of stroke during sleep. There were no differences between the 2 groups with respect to acute-case fatality.