Impact of laboratory-based frailty assessment on clinical outcomes following endovascular thrombectomy in elderly patients with acute ischemic stroke

Abstract

Objective: To investigate the prognostic value of frailty assessed by laboratory-based frailty index (FI-Lab) in elderly patients with acute ischemic stroke (AIS) undergoing endovascular thrombectomy (EVT).

Methods: We conducted a single-center retrospective cohort study of elderly AIS patients who underwent EVT between January 2018 and April 2024. FI-Lab was constructed using a deficit accumulation model incorporating 44 laboratory parameters. Patients were categorized as robust (<0.20), pre-frail (0.20-0.35), or frail (≥0.35) based on established cutpoints. The primary endpoint was 90-day mortality; secondary endpoints included 90-day poor functional outcome and in-hospital mortality. We used multivariable logistic regression to examine associations between frailty and outcomes, restricted cubic spline analysis to assess dose-response relationships.

Results: The study included 335 patients: 107 robust (31.9%), 170 pre-frail (50.7%), and 58 frail (17.3%). Ninety-day mortality increased with frailty severity: 12.1% (robust), 24.1% (pre-frail), and 34.5% (frail) (P=0.003). In fully adjusted models, pre-frail patients had 2.33-fold higher 90-day mortality risk compared with robust patients (95% CI: 1.07-5.37, P=0.038), while frail patients had 5.70-fold higher risk (95% CI: 2.22-15.46, P<0.001). Similarly, frail patients showed increased risks of poor functional outcome (adjusted odds ratio [OR]=4.05, 95% CI: 1.68-10.33, P=0.002) and in-hospital mortality (adjusted OR=6.34, 95% CI: 2.16-20.40, P=0.001). Each 0.1-unit increase in FI-Lab as a continuous variable was associated with 99%, 67%, and 105% higher risks of 90-day mortality, poor functional outcome, and in-hospital mortality, respectively (all P<0.05). Restricted cubic spline analysis confirmed significant linear dose-response relationships between FI-Lab and all adverse outcomes (all P-nonlinear >0.05). No significant interactions were observed across subgroups (all P for interaction >0.05).

Conclusion: Laboratory-based frailty assessment independently predicts adverse outcomes following EVT in elderly AIS patients. FI-Lab provides an objective, standardized tool for risk stratification and clinical decision-making in this population.