Abstract Number: Esoc2026a448 Sex Differences in Outcomes After Acute Stroke in a Chinese Population: A Post-Hoc Analysis of the Interact4 Trial

Abstract Background and aims Sex-related differences in outcomes after acute stroke remain incompletely understood and may vary by stroke subtype. We conducted a post-hoc analysis of the INTERACT4 trial to evaluate the association between sex and 90-day outcomes and whether this association differs by stroke subtype. Methods INTERACT4 is a multicenter, ambulance-delivered, prospective, randomized, clinical trial in Chinese patients suspected with acute stroke. We included participants with available 90-day follow-up and excluded stroke mimics. The primary outcome was 90-day modified Rankin Scale (mRS) shift; secondary outcomes included functional independence and death. Ordinal/logistic regression models estimated adjusted odds ratios (ORs). Effect modification by stroke subtype was tested using interaction terms. Results Among all stroke patients (female n=863; male n=1377), women were older, had different vascular risk profiles, and presented with more severe neurological deficits on hospital arrival. Overall, sex was not independently associated with 90-day mRS shift after adjustment (OR 1.03, 95% CI 0.86-1.23; P=0.741). Associations differed by subtype: in AIS, male sex was associated with reduced odds of worse mRS shift (OR 0.78, 95% CI 0.61-0.99; P=0.043), whereas in ICH, male sex was associated with worse mRS shift (OR 1.44, 95% CI 1.10-1.89; P=0.008), higher mortality (OR 1.80, 95% CI 1.20-2.71; P=0.005), and lower functional independence (OR 0.60, 95% CI 0.41–0.89; P=0.012). Interactions were significant for mRS shift (P0.001), functional independence (P=0.009), and death (P=0.035). Conclusions In this Chinese trial population, sex-outcome associations differed by stroke subtype: male favored outcomes in AIS, while female favored outcomes in ICH. Conflict of interest nothing to disclose