Comparison of prestroke frailty and disability for outcome prediction in older stroke patients

Prestroke disability, measured by the modified Rankin Scale (mRS), is routinely used in older (≥65 years) patients to predict stroke outcomes. Frailty, a common geriatric syndrome, is also associated with poor health outcomes but is rarely assessed in older stroke patients. The Clinical Frailty Scale (CFS) is a simple frailty assessment tool; however, its prognostic value in stroke clinical practice remains uncertain. This study compares the predictive value of prestroke mRS and CFS for stroke outcomes in older patients.

We included 4086 older patients with acute stroke (82.6 % ischemic), consecutively admitted to an Italian hospital. The median age was 81 years (25th-75th percentile: 75-87 years). Prestroke mRS was assessed at admission, while prestroke CFS was retrospectively evaluated from medical records. Multivariable-adjusted models tested the association of each scale with prolonged admission, unfavorable discharge setting, and mortality at 30 days and 1 year. For each outcome, the predictive value of the mRS and CFS scales was compared using the difference in Akaike's Information Criterion (AIC) between the respective models (AIC_mRS-CFS).

Both mRS and CFS were positively associated with unfavorable discharge and mortality and inversely associated with prolonged admission. However, based on AIC_mRS-CFS, CFS was a stronger outcome predictor than mRS. In ischemic stroke patients receiving reperfusion therapies, CFS was also superior to mRS in predicting neurological improvement following treatment and the likelihood of discharge to long-term care.

Compared to prestroke mRS, prestroke CFS may offer additional prognostic information in older stroke patients.