Espessura do músculo adutor do polegar para avaliação nutricional de portadores de doença renal crônica em tratamento conservador

Abstract

Introduction: Chronic kidney disease (CKD) is one of the greatest challenges to public health, since it has important economic and social impacts. It causes changes in body composition, such as a decrease in muscle mass, which is related to depression, cardiometabolic complications, poor quality of life and worse prognosis. Early detection of muscle mass depletion reduces the risks inherent in sarcopenia, prevents the fragility syndrome, promotes well-being and improves prognosis. However, the simple and accurate methods for its evaluation are limited, since changes in body water volume and bone mass contribute to errors. Thus, new anthropometric measures arise, such as the assessment of the thickness of the adductor muscle of the thumb (APMT), a simple, low-cost, non-invasive procedure that correlates with lean mass. Objective: To evaluate the APMT, obtained by adipometer and ultrasonography, as a predictor of the nutritional status of patients with chronic kidney disease under conservative treatment. Methods: Cross-sectional epidemiological study, including patients with CKD in stages 3 to 5. Socioeconomic, clinical and anthropometric data were obtained: weight; height; circumferences of calf (CC), arm (CA) and brachial muscle (CBM); APMT, measured by the adipometer and ultrasonography, and body composition by bipolar and tetrapolar bioimpedance. The concordances between the APMT by both methods were evaluated by the intraclass correlation coefficient and the Bland & Altman graph was produced. APMT were correlated with BMI, CC, CA, CBM, lean mass tissue (LTM), lean mass tissue index and body cell mass (BCM) by Pearson's correlation. The measure was compared according to the CKD stage, socioeconomic data, physical activity and nutritional status. Receiver Operating Characteristic (ROC) curves were produced considering the lean tissue index as the reference standard. The cut-off point was defined by the Youden index. Results: The concordance between APMT obtained by adipometer with APMT and APMT associated to the interosseous muscle, as measured by ultrasonography, was weak (r <0.4). With APMT associated to the interosseous muscle of the non-dominant hand, it was moderate (r = 0.50). The APMT measured by adipometer was moderately correlated to BMI, CC, CA, CBM, LTM, LTM Index and BCM (r = 0.30-0.70). The APMT measured by ultrasonography was poorly correlated to CC, CBM, LTM, LTM Index and BCM; when the thickness of the interosseous muscle was associated, there was a weak correlation with CC, CA, CBM, LTM and BCM (r <0.30). APMT was lower in the malnourished and / or depleted muscle mass and higher in men practicing physical activity (p <0.05). Analysis of the ROC curve determined cut points of 15.33 mm for females and 20.33 mm for males, with accuracy of 72.22% and 62.50%, respectively. Conclusion: APMT presented poor or moderate agreement among the methods. APMT is able to estimate muscle mass and the suggested cutoff point is useful to rule out the likelihood of muscle mass depletion. It is recommended that it be used in a complementary way in the nutritional evaluation.