Yubi-Wakka Test for Sarcopenia Screening in the Community: Comparative Agreement, Diagnostic Performance and Validity with Calf Circumference Measurements

Screening tools such as calf circumference (CC) and Yubi-wakka (finger-ring) test have been recognized as effective tools by Asian Working Group for Sarcopenia 2019 (AWGS'19) for sarcopenia screening but their comparative agreement, diagnostic performance and validity are unclear. This study aims to determine: (i)agreement between calf and finger-ring circumference, (ii)diagnostic performance for low muscle mass and AWGS'19 sarcopenia diagnosis, (iii)correlation with muscle mass, strength, and physical performance, and (iv)association with frailty, life space mobility and physical activity. We studied 187 healthy community-dwelling older adults (mean age=66.8+7.0years) from the GERILABS-2 study. CC was measured via (i) both calves in sitting and standing positions, and (ii) Yubi-wakka test by encircling the thickest part of the non-dominant calf with index fingers and thumbs of both hands. We performed Cohen's kappa to check for agreement, area under receiver operating characteristic curve (AUC) to compare diagnostic performance, partial correlations adjusted for age and gender to compare convergent validity, and logistic regression to determine predictive validity for outcome measures. Sarcopenia prevalence was 24.0% (AWGS'19). Yubi-wakka identified 16.6% of participants as screen-positive ("smaller"), showing moderate agreement only with non-dominant sitting CC measurements (k=0.421,p