Blood-based frailty index in patients with acute ischemic stroke undergoing endovascular treatment

Introduction: Frailty is a syndrome depicting vulnerability of multiple physiological systems to stressors. Frailty measures, such as Hospital Frailty Risk Score (HFRS), can be used to identify frailty and predict outcome more reliably. Our aim was to analyse a blood-based frailty index (FI-B) at admission for prediction outcome of patients with acute ischemic stroke (AIS) undergoing endovascular treatment (EVT). Methods: We conducted a retrospective study of consecutive AIS patients undergoing EVT in a single tertiary centre during a period of five years. A set of eighteen blood parameters at admission were collected and nine of these were utilized to calculate FI-B. We analysed the relationship between FI-B and HFRS. We examined the baseline characteristics of the study population based on FI-B-tertiles. Multivariable regression models were employed to ascertain the association between FI-B and in-hospital mortality, 3-month mortality and 3-month functional outcome. Results: The final study population comprised 489 patients, with a median age of 75.6 years, 49.5% of patients were male. The FI-B exhibited a weak positive correlation with HFRS (rho=0.113, p=0.016). Patients in higher FI-B-tertiles were older and more frequently presented with pre-stroke functional dependence and comorbidities. Moreover, an increasing FI-B was independently associated with increased likelihood of in-hospital mortality (adjusted odds ratio [aOR]=1.29, 95% confidence interval [95%CI]=1.14-1.47), 3-month mortality (aOR=1.26, 95%CI=1.11-1.43), and of increasing 3-month functional disability measured by utility-weighted modified Rankin Scale (common aOR=0.84, 95%CI=0.76-0.93). Conclusion: A frailty index based on blood values at admission was able to identify frailty in AIS patients undergoing EVT and was an independent predictor of short- and medium-term outcome after stroke.