Validity of calf circumference for estimating skeletal muscle mass for Asian patients after stroke

The aims of this study was to determine the optimal cutoff values of non-paretic calf circumference (CC) that are indicative of low skeletal muscle mass and examine the association between a low CC and rehabilitation outcomes.

This was a retrospective cohort study that included 628 patients in convalescent rehabilitation wards in Japan. Patients in post-stroke rehabilitation who were ≥20 y of age were included. We examined the agreement between CC on the non-paretic side and a low skeletal muscle mass index (SMI) measured by bioelectrical impedance analysis. We also confirmed the correlation between sarcopenia defined by CC and handgrip strength, and sarcopenia according to Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Functional Independent Measure (FIM) at discharge and discharge to home outcomes were compared between patients with a high CC and those with a low CC.

Of the 628 patients included in the study, 408 (170 women; mean age, 72 y) were analyzed. The optimal cutoff values of CC were 33 cm for men (sensitivity and specificity, 0.798 and 0.840, respectively) and 32 cm for women (0.847 and 0.818, respectively). The sensitivity and specificity of CC-based sarcopenia against the AWGS criteria were 0.752 and 1.000 for men and 0.800 and 1.000 for women, respectively. Patients with a low CC had a significantly lower FIM and proportion of home discharge than those with a high CC.

The optimal cutoff values of non-paretic CC for a low SMI were 33 cm for male and 32 cm for female Asian stroke rehabilitation patients. Sarcopenia can be defined using CC instead of SMI.