Abstract Number: Esoc2026a2469 Utility of Cardiovascular Risk Prediction for Primary Prevention of Young Tia/Stroke in Relation to Aetiology and Sex: A Population-Based Study

Abstract Background and aims Incidence of stroke is increasing at younger ages. Cardiovascular risk prediction models are used to target prevention, but may be ineffective in identifying younger individuals at risk of stroke due to the frequent non-atherosclerotic aetiology of ‘young stroke’, particularly in women. We therefore determined the premorbid predicted 10-year CV-risk in young stroke patients in relation to aetiology and sex. Methods In a UK population-based study (2002-2023) of all acute vascular events, we prospectively determined premorbid 10-year CV-risk (QRISK3®CV scores) for all individuals with a first vascular event at age 30-45, stratified by type (TIA/stroke versus coronary/peripheral vascular-ACS/PVD) and aetiology (atherosclerotic vs non-atherosclerotic). Results Of 211 individuals with incident vascular events, median 10-year predicted CV-risk was higher (p0.0001; Figure) in the 69 with ACS/PVD events (4.4%, IQR=2.2-7.6) than in the 142 with TIA/stroke (2.4%, 1.1-4.5%; p0.0001), driven mainly by a low predicted risk (1.8%,0.9-3.7%) in the 112 (79%) TIA/strokes with non-atherosclerotic aetiologies. By contrast, the median predicted risk in those with atherosclerotic TIA/stroke (4.7%,3.1-7.9%) was similar to that in ACS/PVD events. Non-atherosclerotic aetiology particularly predominated (56/65) in women with TIA/stroke, resulting in a lower CV-risk in women overall versus men with TIA/stroke: 1.4%(0.7-2.9%) vs 3.5%(1.6-5.4%). Conclusions The majority of vascular events at age 30-44 years are cerebrovascular, most of which have non-atherosclerotic aetiologies and low predicted 10-year CV-risks, particularly in women, thereby undermining the impact of risk-based prevention of young stroke in primary care. Conflict of interest Cathy Scott: nothing to disclose Figure 1 - belongs to Conclusions