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

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.

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.

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).

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;100:644-652.