M.R.PIODENA-APORTADERA1, S.LAU1, J.CHEW1, J.P.LIM1, N.HAFIZAH1, Y.Y.DING1, W.S.LIM1
Tan Tock Seng Hospital1
Sarcopenia confers increased risk of negative outcomes, including frailty, falls and mortality. Although recommended as screening tool for sarcopenia, there is no consensus on calf circumference (CC) measurement by position (sitting, standing) and laterality (right, left). This study aims to determine: (i)agreement between CC measurements, (ii)correlation with muscle function, and (iii)diagnostic performance for sarcopenia screening.
We studied 176 independent community-dwelling older adults (mean age: 66.8±7.1years, 72.7% female) from the GeriLABS-2 study. CC was measured via non-elastic tape in 4 ways: both sides in standing and sitting positions. Sarcopenia was diagnosed using Asian Working Group for Sarcopenia 2019 criteria. We performed Bland-Altman plot for agreement; partial correlations for muscle function to compare convergent validity; and receiver operating characteristic curve analysis to compare diagnostic performance.
Sarcopenia prevalence was 17.4%. Sitting CC was larger than standing regardless of laterality (right:35.3+3.0cm vs 34.6+2.7cm,p<0.001; left:35.4+3.0cm vs 34.7+2.8cm,p<0.001), consistent with systematic bias on Bland-Altman plots showing overestimation of sitting over standing measurements (right: bias 0.7cm,95% CI:-0.5 to 1.9; left: bias 0.67cm,95% CI: -0.35 to 1.68). Right standing showed highest correlation for knee-extension, 5-time chair-stand and Short Physical Performance Battery (r=0.19-0.24,p<0.05, adjusted for age and gender) and best diagnostic performance (AUC=0.817,95% CI:0.743-0.890) amongst the measurements (AUC=0.786-0.816). Optimal cut-offs for sarcopenia screening are <35cm for males (sensitivity:92.3%, specificity:65.6%) and <34cm for females (sensitivity:85.2%, specificity:62.2%).
CC measurements are not inter-changeable due to systematic bias with overestimation by sitting measurements. Right standing CC is recommended for sarcopenia screening in community-dwelling older adults due to convergent validity and superior diagnostic performance.