CYP2C19 and stroke disorder: We also performed analysis including all events during the prescribing period (the primary analysis excluded events in the first 7 days of prescribing because the effect of clopidogrel on platelet aggregation was significantly different between CYP2C19 genotype groups after 7–10 days in a study of 375 patients).23 This period included six strokes and changed the estimates from (HR 1.53, 95% CI 1.04 to 2.26, p=0.031) to (HR 1.45, 95% CI 0.99 to 2.13, p=0.053).