Discharge Function and Length of Stay for Patients with Stroke are Predicted by Lower Extremity Muscle Force on Admission to Rehabilitation

OBJECTIVE: We sought to determine the relative value of lower extremity muscle strength as a predictor of discharge function and length of stay of patients with stroke. METHODS: We studied 72 patients undergoing inpatient rehabilitation after a stroke and documented their outcome using length of stay and function as measured by the Functional Independence Measure (FIM) at discharge. RESULTS: Knee-extension force and the total force of four lower extremity muscle actions (hip flexion, knee extension, knee flexion, and ankle dorsiflexion) were correlated significantly with discharge FIM and length of stay. The correlations involving the actions of the weaker side were higher. Admission FIM was also correlated significantly with discharge FIM and length of stay. Previous stroke and age were correlated significantly with discharge FIM but not length of stay. The set of variables offering the best explanation of discharge FIM (R = 0.867) was admission FIM, admission FIM squared, age, and total force of the weaker side. The set of variables offering the best explanation of length of stay (R = 0.812) was knee-extension force of the weaker side squared, admission FIM, admission FIM squared, and age. CONCLUSIONS: Lower extremity muscle force of the weaker side on admission has value as a predictor of function at discharge and length of stay for patients with stroke admitted to inpatient rehabilitation. Muscle force, therefore, is a reasonable target of measurement and treatment. Knowledge of muscle force on admission can assist clinicians, patients, families, and others to anticipate patient outcomes after rehabilitation.