Background and Purpose-Controversy regarding the risks and benefits of thro
mbolysis has not been helped by the perception that some trials were "posit
ive" and others "negative" on their primary outcome measure of either "good
" or "poor" functional outcome. We wondered whether the definition of good
or poor functional outcome might have contributed to this perception, and w
hat effect altering the definition might have on the individual trials and
on the systematic review of all the trials combined.
Methods-We analyzed data on functional outcome, extracted from the randomiz
ed trials of thrombolysis in acute ischemic stroke, according to good (modi
fied Rankin scale scores of 0 to 1 versus 2 to 6) and poor (modified Rankin
0 to 2 versus 3 to 6) functional outcome, to determine the effects of thro
Results-Twelve trials (4342 patients, treated up to 6 hours after stroke) c
ontributed to this analysis. Overall, there was no difference in the estima
te of treatment effect between the 2 definitions (modified Rankin 0 to 2 ve
rsus 3 to 6, and 0 to 1 versus 2 to 6 [ORs 0.83 and 0.79, respectively]). H
owever, the apparent "success" of several individual trials did alter.
Conclusions-We should not place undue emphasis on the results of individual
trials, when a change of a single point on the Rankin scale can make the d
ifference between "success" and "failure." Overall, by either analysis, the
re was a significant benefit in patients treated with thrombolysis up to 6
hours after stroke.