Cut-off values for severe low muscle strength and skeletal muscle mass in post-acute patients with sarcopenia

Aim: This study aimed to calculate the cut-off values for severe decline in muscle strength and skeletal muscle mass in post-acute patients with sarcopenia and to determine their effect on activities of daily living. Methods: This retrospective cohort study included patients with sarcopenia consecutively admitted to a Japanese rehabilitation hospital between 2014 and 2016. Sarcopenia was diagnosed based on handgrip strength and skeletal muscle mass index. The outcome was the functional independence measure of motor function at discharge. Cut-off values for predicting severe decline in handgrip strength and skeletal muscle mass index were calculated separately by sex. Values below the cut-off were used to define severely low handgrip strength and severely low skeletal muscle mass index. Results: Overall, 451 patients (median age, 83 years; 61.4% women) were evaluated. The median functional independence measure of motor function score at discharge was 57. The optimal cut-off values for severely low handgrip strength were 9.0 kg for women and 14.6 kg for men, and those for severely low skeletal muscle mass index were 4.6 kg/m(2) for women and 5.6 kg/m(2) for men. Severely low handgrip strength and skeletal muscle mass index were independently associated with the functional independence measure of motor function score at discharge (beta = -0.178, P = 0.005). Conclusions: In post-acute patients with sarcopenia, a severe decline in muscle strength and skeletal muscle mass is further negatively associated with an improvement in activities of daily living. The cut-off values herein can serve as indicators to assess sarcopenia severity.