Variations Between Countries in Outcome After Stroke in the International Stroke Trial (IST)

Abstract

Adjustment for case mix explained only some of the variation in outcome between countries. The residual differences in outcome were too large to be explained by variations in care and most likely reflect differences in unmeasured baseline factors. These findings demonstrate the need to achieve balance of treatment and control within each country in multinational randomized controlled stroke trials and the need for caution in the interpretation of nonrandomized comparisons of outcome after stroke between countries.