Impact of post-stroke frailty index on functional outcomes: a retrospective cohort study.

Background: The frailty index (FI) has been reported as a useful measure for assessing premorbid conditions in stroke patients; however, its significance in evaluating post-stroke status remains unclear.

Aims: This study aims to clarify the role of FI as a tool for assessing post-stroke conditions.

Methods: This retrospective cohort study included stroke patients admitted to an acute-care hospital. The FI, based on the cumulative deficit model and comprising comorbidities, symptoms, and functional limitations, was assessed using 33 items at discharge from the acute-care hospital. The primary outcome was the mRS at three months post-onset. Multiple logistic regression was performed with poor functional outcomes as the dependent variable and mRS at discharge, FI at discharge, and both as explanatory variables. The cutoff value of FI for poor functional outcomes was also determined using a receiver operating characteristic (ROC) curve.

Results: A total of 241 patients with acute stroke were included in the final analysis. The median length of hospital stay was 14 days (IQR 9-20). In the adjusted model including both FI and mRS at discharge, FI at discharge was significantly associated with poor outcomes (aOR = 3.43, 95% CI = 1.66-7.09,  < 0.001). The cutoff value of FI for poor functional prognosis derived from the ROC curve was 0.288 (sensitivity 0.816, specificity 0.911).

Conclusions: Our findings indicate that post-stroke FI is independently associated with poor outcomes. It is important to incorporate FI in addition to traditional assessment tools to predict post-stroke prognosis.