Comparisons of sarcopenia defined by IWGS and EWGSOP criteria among older people: results from the I-Lan longitudinal aging study.

OBJECTIVE: To compare clinical characteristics of sarcopenia defined by the International Working Group on Sarcopenia (IWGS) and European Working Group on Sarcopenia in Older People (EWGSOP) criteria among older people in Taiwan.

DESIGN: A prospective population-based community study.

SETTING: I-Lan County of Taiwan.

PARTICIPANTS: A total of 100 young healthy volunteers and 408 elderly people.

INTERVENTION: None.

MEASUREMENTS: Anthropometry, skeletal muscle mass measured by dual x-ray absorptiometry, relative appendicular skeletal muscle index (RASM), percentage skeletal muscle index (SMI), 6-meter walking speed, and handgrip strength.

RESULTS: The prevalence of sarcopenia was 5.8% to 14.9% in men and 4.1% to 16.6% in women according to IWGS and EWGSOP criteria by using RASM or SMI as the muscle mass indices. The agreement of sarcopenia diagnosed by IWGS and EWGSOP criteria was only fair by using either RASM or SMI (kappa = 0.448 by RASM, kappa = 0.471 by SMI). The prevalence of sarcopenia was lower by the IWGS definition than the EWGSOP definition, but it was remarkably lower by using RASM than SMI in both criteria. Overall, sarcopenic individuals defined by SMI were older, had a higher BMI but similar total skeletal muscle mass, and had poorer muscle strength and physical performance than nonsarcopenic individuals. However, by using RASM, sarcopenic individuals had less total skeletal muscle mass but similar BMI than nonsarcopenic individuals. Multivariable logistic regression showed that age was the strongest associative factor for sarcopenia in both IWGS and EWGSOP criteria. Obesity played a neutral role in sarcopenia when it is defined by using RASM, but significantly increased the risk of sarcopenia in both criteria by using SMI.

CONCLUSION: The agreement of sarcopenia defined by IWGS and EWGSOP was only fair, and the prevalence varied largely by using different skeletal muscle mass indices. Proper selections for cutoff values of handgrip strength, walking speed, and skeletal muscle indices with full considerations of gender and ethnic differences were of critical importance to reach the universal diagnostic criteria for sarcopenia internationally.