Age Is an Effect Modifier of Thrombectomy Benefit in a Socioeconomically Vulnerable Stroke Population

Objective Randomized trials from high‐income countries have shown that endovascular treatment (EVT) yields similar benefits in elderly and non‐elderly patients with large vessel occlusion stroke (LVOS). However, evidence from low/middle‐income countries remains scarce. We aimed to assess the impact of age on outcomes and determine whether age modifies the effect of EVT under the resource‐limited conditions of a public healthcare system in a developing country. Methods Pre‐specified subgroup analysis of the RESILIENT trial, a multicenter, randomized, controlled trial in Brazil comparing EVT versus medical treatment alone in anterior circulation LVOS. Patients were categorized as non‐elderly (<70 years), elderly (≥70 years), and very elderly (≥80 years). The primary endpoint was functional independence (modified Rankin scale 0–2) at 90 days. Logistic regression was performed to identify independent predictors of outcome and to assess age as an effect modifier. Results Among 221 randomized patients (47.1% females; median [IQR] National Institutes of Health Stroke Scale, 18 [14–21]), 89 (40.2%) were elderly and 37 (16.7%) very elderly. Increasing age was independently associated with lower odds of functional independence in the entire study population (odds ratio [OR]: 0.97; 95% confidence interval [CI]: 0.95–0.99, p = 0.01). Age significantly modified the treatment effect of EVT. Non‐elderly patients derived substantial benefit from EVT (OR: 4.08; 95% CI: 1.71–9.76), whereas the benefit was attenuated in elderly (OR: 0.90; 95% CI: 0.17–5.42; p interaction = 0.03) and very elderly (OR: 0.36; 95% CI: 0.11–3.21; p interaction = 0.03). Interpretation The effect of EVT appears significantly diminished among elderly patients in a public healthcare system in a developing country. Further studies are needed to understand the mechanism underlying these findings and properly assess the efficacy of EVT in this vulnerable population. ANN NEUROL 2026