Letter by Zedde et al Regarding Article, "Sex Differences and Functional Outcome After Intravenous Thrombolysis".

We have read with great interest the article by Spaander et al.1 The purpose of the study was to compare outcome after intravenous thrombolysis (IVT) between females and males with regard to age in a large multicenter European cohort. Data were obtained from IVT registries of 12 European tertiary hospitals. The authors concluded that females compared with males had worse functional outcome when treated by IVT. Conversely, the conclusions provided by SIST-ISTR registry2 (Safe Implementation of Thrombolysis in Stroke–International Stroke Thrombolysis Register) and International Stroke Trial 3 (IST3)3 data reported no differences regarding functional outcome between the sexes. In fact, the IST-3 trial3 had no age limits for study inclusion, and >50% of included patients were females. Data from this trial do not show any difference in outcome among 13 prespecified subgroups of treated and control subjects, including sex. IST-3 trial has been designed as a pragmatic trial to be as inclusive as possible, leading to the highest percentage of females in an acute RCT. Moreover, the latest meta-analysis4 …