Predicting long-term outcome after acute ischemic stroke: a simple index works in patients from controlled clinical trials.
OBJECTIVE
An early and reliable prognosis for recovery in stroke patients is important for initiation of individual treatment and for informing patients and relatives. We recently developed and validated models for predicting survival and functional independence within 3 months after acute stroke, based on age and the National Institutes of Health Stroke Scale score assessed within 6 hours after stroke. Herein we demonstrate the applicability of our models in an independent sample of patients from controlled clinical trials.


METHODS
The prognostic models were used to predict survival and functional recovery in 5419 patients from the Virtual International Stroke Trials Archive (VISTA). Furthermore, we tried to improve the accuracy by adapting intercepts and estimating new model parameters.


RESULTS
The original models were able to correctly classify 70.4% (survival) and 72.9% (functional recovery) of patients. Because the prediction was slightly pessimistic for patients in the controlled trials, adapting the intercept improved the accuracy to 74.8% (survival) and 74.0% (functional recovery). Novel estimation of parameters, however, yielded no relevant further improvement.


CONCLUSIONS
For acute ischemic stroke patients included in controlled trials, our easy-to-apply prognostic models based on age and National Institutes of Health Stroke Scale score correctly predicted survival and functional recovery after 3 months. Furthermore, a simple adaptation helps to adjust for a different prognosis and is recommended if a large data set is available.
König
Inke R
IR
Institut für Medizinische Biometrie und Statistik, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. inke.koenig@imbs.uni-luebeck.de
Ziegler
Andreas
A
Bluhmki
Erich
E
Hacke
Werner
W
Bath
Philip M W
PM
Sacco
Ralph L
RL
Diener
Hans C
HC
Weimar
Christian
C
D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000453:epidemiology* / Q000534:rehabilitation; D018849:Controlled Clinical Trials as Topic / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D011379:Prognosis; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology*; D000071939:Stroke Rehabilitation; D013534:Survival