ABSTRACT
OBJECTIVES: To investigate the predictive value of the BIA-derived phase angle with respect to the functional prognosis and baseline sarcopenia in patients undergoing post-stroke rehabilitation. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: Overall, 577 Japanese patients admitted to a post-acute care hospital from 2016 to 2020 were recruited. MEASUREMENTS: Body composition analysis, which included BIA-derived phase angle and skeletal muscle mass, was performed using bioelectrical impedance analysis (BIA). Study outcomes included physical function assessed using the Functional Independence Measure (FIM-motor) and the level of dysphagia assessed using the Food Intake LEVEL Scale (FILS). Sarcopenia was defined as the loss of skeletal muscle mass and decreased muscle strength. Receiver operating characteristic curves were used to calculate the optimal cutoff value of BIA-derived phase angle to diagnose sarcopenia. Multivariate analyses were used to determine whether the BIA-derived phase angle at admission was associated with outcomes at discharge and baseline sarcopenia. RESULTS: After enrollment, 499 patients (mean age: 74.0 ± 13.1 years; 52.0% men) were examined. The median FIM-motor and FILS scores at admission were 47 (20-69) and 8 (7-10), respectively. Sarcopenia was observed in 43.2% of patients. After adjusting for potential confounders, BIA-derived phase angle was positively associated with FIM-motor scores at discharge (ß = 0.134, P < 0.001), FIM-motor score gain (ß = 2.504, P < 0.001), and FILS scores at discharge (ß = 0.120, P = 0.039). BIA-derived phase angle was negatively associated with the sarcopenia diagnosis at baseline (odds ratio = -0.409, P < 0.001); its cutoff value was 4.76° (sensitivity 0.800, specificity 0.790, P < 0.001) for sarcopenia diagnosis in men and 4.11° (sensitivity 0.735, specificity 0.829, P < 0.001) in women. CONCLUSION: BIA-derived phase angle was positively associated with the recovery of physical function and dysphagia level and negatively associated with baseline sarcopenia in patients undergoing post-stroke rehabilitation. The BIA-derived phase angle cutoff for sarcopenia diagnosis was 4.76° for men and 4.11° for women.
