ABSTRACT NUMBER: ESOC2026YS237 SOCIOECONOMIC INEQUALITIES IN POST-STROKE OUTCOMES PERSIST, BUT CAUSAL MECHANISMS REMAIN UNCLEAR. WE USED COUNTERFACTUAL MEDIATION ANALYSIS TO QUANTIFY THESE PATHWAYS

Abstract Background and aims Socioeconomic inequalities in post-stroke outcomes persist, but causal mechanisms remain unclear. We used counterfactual mediation analysis to quantify these pathways. Methods We included all first-ever stroke patients from the South London Stroke Register (1995-2025), stratified by decade. Socioeconomic status (SES) was measured using Index of Multiple Deprivation quintiles (1-2 vs 3-5). Outcomes at 3-months, 1-year and 5-years included disability (Barthel Index), dependency (Frenchay Activities Index), quality of life (SF-12), and depression/anxiety (HADS). We estimated total effects using regression models adjusted for age and sex, then conducted counterfactual mediation analysis where inequalities existed. Mediators included cardiovascular risk factors (hypertension, diabetes, smoking, atrial fibrillation, alcohol, hypercholesterolaemia) at baseline and follow-up, stroke severity, stroke unit access, secondary prevention medications, and rehabilitation. Multiple imputation addressed missing data. Results Preeliminary results, analysis ongoing. Conflict of interest Camila Pantoja-Ruiz: Nothing to disclose