Temporal Trends in Stroke Severity and Prior Antithrombotic Use Among Acute Ischemic Stroke Patients in Japan

Background: Few existing stroke registries allow for evaluation of stroke severity, stroke subtype and antithrombotic usage prior to stroke onset over a given time period. The present study aimed to elucidate temporal trends in initial presenting stroke severity, stroke subtype and prior antithrombotic use over a 12-year period in a Japanese multicenter stroke registry. Methods and Results: We included 71,017 acute ischemic stroke patients (72 +/- 12 years old; 27,445 women) from the Japan Standard Stroke Registry Study (JSSRS) who were admitted to 94 hospitals between 2001 and 2012. The mean age of stroke onset increased gradually over time (P<0.001). Cardioembolic stroke patients (n=19,247) exhibited more severe NIHSS scores when compared with those with non-cardioembolic stroke (n=50,427). The proportion of cardioembolic stroke patients tended to increase over time, rising from 25.9% in 2001-2002 to 30.2% in 2011-2012 (P<0.001). Among the cardioembolic stroke patients, the frequency of prior anticoagulant use significantly increased from 15.6% in 2001-2002 to 24.8% in 2011-2012 (P<0.001). The frequency of prior antiplatelet use increased from 2001-2002 to 2007-2008 but decreased after 2007-2008. Among both cardioembolic and non-cardioembolic stroke patients, initial stroke severity at admission decreased over time, particularly after 2008. Conclusions: In this Japanese study, the mean age of ischemic stroke onset increased, while the initial neurological severity at presentation decreased, over a 12-year period.