Background and Purpose: Lower extremity function is a strong predictor for functional outcome and death in a variety of pathological status. National Institute of Health Stroke Scale (NIHSS) is a world-wide standard scoring system for stroke patients; however, it is not sufficient to evaluate lower extremity function. Short Physical Performance Battery (SPPB) is a simple assessment tool for lower extremity function, consists of standing balance, walking speed, and repetitive standing (range: 0-12, 12: high function). SPPB can predict adverse events, such as disability and mortality in elderly population, but its disease specific utility for stroke patients is still unknown. The purpose of this study was to determine whether SPPB score predicts functional independence and death for acute stroke.
Methods: Between April 2013 and November 2014, 410 consecutive stroke patients admitted within 7 days after the onset. Patients with premorbid modified Rankin Scale (mRS) of 0-2, and evaluated SPPB at 7th days after the admission were enrolled in this study. Clinical data were analyzed using univariate and multivariate model to assess functional independence (defined as mRS of 0-2) at 3 months and 1 year mortality adjusting covariates to investigate the association between SPPB and functional independence or death. Receiver operating characteristics (ROC) curve analysis was performed for detecting optimal cut-off value.
Results:A total of 243 patients (mean age 73.8 years, male 58.4%) were included in this study. Of them, 132 (54.3%) patients were independent at 3 months follow up, and 14 (5.8%) patients have died. Median SPPB score at 7th days after the admission was 6 (IQR: 1-11). After adjusting age, sex, BMI, NIHSS score on admission, SPPB score at 7th days after the admission was significantly associated with 3-month functional independence (odds ratio, 1.48; 95%CI, 1.29-1.69; p<0.001) and 1-year death (hazard ratio, 0.36; 95% CI, 0.17-0.74; p=0.005). ROC curve analysis revealed the cut-off point of SPPB for functional independence was 6 (AUC:0.88, 95%CI, 0.83-0.93, p<0.001, sensitivity: 0.83, specificity:0.84).
Conclusions: Early SPPB score is a useful assessment tool in predicting functional independence and death for acute stroke patients.