Avaliação da composição corporal por densitometria óssea de dupla absorção de raio-x (DXA) e validação de pontos de corte de circunferência da panturrilha para rastreio de Sarcopenia com base na baixa massa magra apendicular por DXA em pessoas idosas.

Abstract

Due to the aging process, physiological changes determine a redistribution of body fat and a reduction in muscle mass. Measuring calf circumference (CC) is a screening tool for sarcopenia, but few studies on the Brazilian population determine cut-off points. This study aims to define CC cut-off points based on appendicular lean mass values using dual-energy X-ray absorptiometry (DXA). This cross-sectional study included elderly individuals aged 60 and over. Participants were selected from the Cognition and Aging Clinic and the Multidisciplinary Care for Robust and At-Risk Elderly Clinic, both at the Jenny de Andrade Faria Institute for Elderly Health Care, Hospital das Clínicas, Federal University of Minas Gerais (UFMG). All participants signed an informed consent form, underwent a geriatric assessment, and had body composition evaluated by DXA. The accuracy of CC cut-off points for identifying patients with low lean mass according to appendicular lean mass adjusted for height squared by DXA was obtained from ROC curves and sensitivity and specificity values. Variables with p<0.20 in the univariate analysis were included in the multivariate logistic regression analysis. Statistical significance was set at p<0.05, and analyses were conducted using STATA, version 16.0. The study included 254 elderly individuals. Cut-off points for men were 35.0 cm (AUC 0.90 [0.83-0.97], sensitivity 90.2%, specificity 72.6%) and for women 34.0 cm (AUC 0.74 [0.66-0.82], sensitivity 77.1%, specificity 60.8%). CC can be used as a sarcopenia screening tool due to its practical application and low cost, offering a good alternative to expensive tools like DXA. Further studies are needed to evaluate other variables that may influence CC cut-off points.