LAUSR

BACKGROUND Recommendations in current guidelines on the use of calf circumference (CC) as a diagnostic measure in sarcopenia is conflicting. In this study, we incorporated CC into conventional models of sarcopenia and compared their predictive scores on mortality. OBJECTIVE To clarify the predictive capacity of CC-added models of sarcopenia on and establish the correlation of CC with mortality risk. DESIGN, SETTING AND SUBJECTS From the National Health and Nutrition Examination Survey 1999-2002, 2,532 participants aged 50-85 and comprising 51.7% male were included. METHODS Our definitions contained four sarcopenic components, low CC (C), low muscle strength (S), low muscle mass (M) and low gait speed (G). Cox proportional hazard models and the receiver-operator characteristic curves for all-cause, cardiovascular (CV) and cancer mortality were conducted to compare the different sarcopenia definitions. RESULTS For all-cause mortality, the hazard ratio (HR) of C + S + M + G was 15.062, which was substantially higher than the conventional definition S + M + G (HR = 6.433). Other CC-added definitions such as C + M (HR = 2.260), C + G (HR = 4.978), C + S + M (HR = 5.761) also revealed higher HR than their without-CC counterparts. Similar patterns were observed in CV mortality, for instance, HR of C + S + M + G was 31.812 comparing to the conventional definition S + M + G (HR = 18.434). Concerning accuracy in predicting mortality, the area under the curve (AUC) of CC + S + G + M (AUC = 0.702) and C + S + G (AUC = 0.708) were higher than the conventional definition S + G + M (AUC = 0.697). A significant correlation was found between CC and each of the three conventional components of sarcopenia. CONCLUSIONS CC-added definitions of sarcopenia correlated with higher all-cause and CV mortality risks. CC is potentially a simple but valuable screening tool for sarcopenia that could improve diagnostic accuracy when used with other parameters.