Abstract WMP10: Sex Difference In Imaging-based Intravenous Thrombolysisfor Ischemic Stroke With Unknown Onset Time: A Pooled Analysis Of Clinical Trials

Introduction:Our prior meta-analysis reported that imaging-based intravenous thrombolysis (IVT) was safe and effective for patients who have had a stroke with an unknown onset time. The aim of this study is to investigate whether sex differences exist in clinical outcomes among this population.Methods:This is a pooled analysis of individual patient-level data acquired from the EOS project, a meta-analysis of clinical trials (PROSPERO, CRD42020166903). Patients treated with imaging-based IVT for stroke with an unknown time of onset were included. The primary outcome was a favorable functional outcome (mRS 0-1) at 90 days. Secondary outcomes were mRS shift towards a better functional outcome and death within 90 days. Sex differences were investigated using mixed-effect logistic or ordinal regression models adjusted for covariates, considering potential heterogeneity across trials.Results:Among 509 patients treated with imaging-based IVT, 204 (40.1%) were women. Compared to men, women were older (70±12 vs. 67±13, p=0.003), more frequently had atrial fibrillation (27.6% vs. 17.2%, p=0.005), and were taking antiplatelets prior to the onset (45.5% vs. 36.4%, p=0.045). Baseline NIHSS score was higher (8.0 (IQR 5-15) vs.6 (4-11), p<0.001), and hours from last-known-well to treatment were longer (11.2 (9.3-12.9) vs. 10.3 (8.1-11.9), p<0.001) in women than men. Favorable outcomes occurred in 80 (40.6%) women and in 150 (49.7%) men (p=0.047). Among women, 19 (9.6%) patients died, compared with 15 (5.0%) patients in men (p=0.042). After multivariate adjustment, female sex was not significantly associated with favorable functional outcome (adjusted odds ratio (OR) 1.01[95% confidential intervals (CI) 0.66-1.54]; p=0.97) nor death (adjusted OR 1.28 [95%CI 0.59-2.76]; p=0.59). Female sex was not associated with a significant shift towards the better functional outcome (common OR 1.07 [95%CI 0.77-1.49]; p=0.70).Conclusions:Pooled data from clinical trials show that in univariate analysis, women had numerically less good functional outcomes following imaging-based IVT among ischemic stroke patients with unknown onset time. However, this sex difference can be explained by higher age and more severe clinical status in women at stroke onset.