Antiplatelet prescription at discharge and one-year outcomes after ischaemic stroke with thrombocytopenia

Background Evidence guiding antiplatelet therapy after ischaemic stroke in patients with thrombocytopenia is limited. We evaluated associations between antiplatelet prescription at discharge and 1-year ischaemic, bleeding and mortality outcomes.Methods We emulated a discharge-landmark treatment assignment among patients with non-cardioembolic ischaemic stroke and platelet counts <100×10³/µL. Treatment assignment was fixed according to the discharge prescription. Propensity-score overlap weighting adjusted for prespecified covariates, including discharge platelet count, discharge modified Rankin Scale >2, lesion location, in-hospital antiplatelet use, do not resuscitate status, and palliative or hospice care. Death was treated as a competing event for recurrent stroke and major bleeding.Results The revised cohort included 329 patients; 179 received antiplatelet therapy and 150 did not. After weighting, all measured covariates were balanced (maximum absolute standardised mean difference, 0.002). Antiplatelet prescription was associated with lower recurrent ischaemic stroke risk (cause-specific HR) 0.41 (95% CI 0.20 to 0.83); Fine–Gray subdistribution HR 0.40 (0.20–0.71). Major bleeding (HR 0.89 (0.28–2.87)) and all-cause death (HR 0.75 (0.38–1.47)) did not differ clearly. Through 365 days, the restricted mean time lost to recurrent ischaemic stroke was 46.7 days lower with antiplatelet prescription (95% CI 13.8 to 80.6 fewer days). Formal interaction tests did not support heterogeneity by stroke subtype or platelet stratum.Conclusions Antiplatelet prescription at discharge was associated with fewer recurrent ischaemic strokes, but bleeding and mortality estimates were imprecise. Residual treatment-selection and sick-stopper bias cannot be excluded; these findings should not be interpreted as causal evidence of safety or mortality benefit.