A Combined Assessment Method of Phase Angle and Skeletal Muscle Index to Better Predict Functional Recovery after Acute Stroke

Objectives: We aimed to investigate whether combination assessment of phase angle (PhA) and skeletal muscle index (SMI), was a possible predictor of physical function at discharge from the hospital in patients with acute stroke. Research methods and procedures: In this retrospective cohort study that was conducted from May 2020 and July 2021, we determined PhA and SMI using bioimpedance analysis (BIA) in patients with acute stroke. Patients were classified as normal, low PhA + SMI group, pre-sarcopenia (low SMI only), and dynapenia (low PhA only) using cut-off points (men: SMI < 7.0 kg/m2, PhA < 4.05 degrees; women: SMI < 5.7 kg/m2, PhA < 3.55 degrees). The main outcome was physical function based on functional independence measure motor (FIM-motor) score at discharge. Multiple regression analysis was used to determine the association between low PhA + SMI and FIM-motor score. Results: We included 244 patients (161 men; mean age, 73.9 years). low PhA + SMI was found in 21 (8.6%) patients. Multiple regression analysis showed that low PhA + SMI was independently associated with the FIM-motor score at discharge (β= -0.099, 95%CI: -0.193,-0.005, p = 0.039). The PhA cutoff values for determining good functional results using receiver operating characteristic (ROC) curves were 5.36 for men (sensitivity = 0.769, specificity = 0.586, area under the curve [AUC] = 0.682), and 3.85 for women (sensitivity = It was 0.881, specificity = 0.481, AUC). Further, pearson correlation coefficient showed that PhA was significantly related to FIM-motor score in patients with mild or moderately severe stroke (mild: r = 0.472, p < 0.001; moderate: r = 0.524, p < 0.001). Conclusions: Combination of low PhA and SMI values at baseline, was an independent predictor of physical function at discharge in patients with acute stroke. The findings highlighted the importance of measuring PhA and SMI using BIA in patients with acute stroke. Keywords: Nutritional status; bioimpedance analysis; functional independence measure motor score; functional recovery; skeletal muscle mass.