Role of Ultrasonography in Estimating Muscle Mass in Sarcopenic Obesity

Abstract

Background: Sarcopenic obesity (SO) is the coexistence of sarcopenia and obesity in an individual. The present study is designed to define the usefulness of skeletal muscle ultrasonography (US) in the definition of SO. Methods: Eighty-nine participants aged ≥65 whose body mass index (BMI, kg/m 2) was ≥30 were consecutively enrolled in an outpatient clinic of geriatric medicine. All underwent comprehensive geriatric assessment. US measurements were obtained in 6 different muscles consisting of core and limb muscles. We defined SO as the presence of low muscle function (defined by a handgrip strength < 27 kg in males and <16 kg in females) and high BMI (≥30). Results: The median age of the participants was 72 (65-85) years; 81% were female, and 35% (n = 31) had SO. Anthropometric parameters that estimate muscle mass were lower in the sarcopenic group, but estimations of muscle mass with bioelectrical impedance analysis (BIA) did not differ between groups. All US estimations of muscle mass were lower in sarcopenic obese participants, albeit not all significantly. RF muscle cross-sectional area (RF CSA) and abdominal subcutaneous fat thickness were most strongly correlated with grip strength (r = 0.477 and r = −508, respectively). Receiver operating characteristic analysis suggested that the optimum cutoff point of RF CSA for SO was ≤5.22 cm 2 , with 95.8% sensitivity and 46.7% specificity (area under the curve: 0.686). Conclusions: US evaluation of muscle mass may be more accurate than BIA-derived skeletal muscle index assessment for the diagnosis of SO.

Intraclass Correlation Coefficient and Reliability of Muscle Mass Measurements

“…8 These elements, which are needed for a proper interpretation of the ICCs, have commonly been missing in general medical literature. Table 1 summarizes the elements reported in the five papers published in the Journal of Parenteral and Enteral Nutrition [1][2][3][4][5] regarding a particular topic, the reliability of muscle mass measurements by different methods. Note that only one study reported, in the methods and/or results, all necessary elements for a proper interpretation of the ICCs or a strategy for choosing.…”

“…In the last year, five papers that reported intraclass correlation coefficients (ICCs) for the reliability of muscle mass measurements were published in the Journal of Parenteral and Enteral Nutrition. [1][2][3][4][5] the degree of correlation and agreement between different measurements and is subject to a variety of statistical assumptions, violations of which may lead to inflated estimates. 6 Based on three different models (one-way random effects, two-way random effects, and two-way mixed effects), two types of measurements (single or average measures), and two output definitions (consistency or absolute agreement), there are, by convention, 10 types of ICCs 7 differentially used for various purposes, such as repeatability and reliability.…”

Cardiovascular Health, Testosterone, and Oxandrolone: Leveraging the Myotrophic-Androgenic Ratio in Males with a Sarcopenic Obese Phenotype

“…Unregulated fluid retention in those severe endocrinological impairments may suffer from exacerbations of concomitant heart disease associated with sarcopenic obesity and low testosterone, such as the cases of heart failure discussed earlier due to increased peripheral resistance from volume overload [96,97]. From a clinical perspective, aromatized TRT leading to potential estradiol conversion and fluid retention may also impact stratification of sarcopenic obesity as studies using different imaging modalities for evaluation of body composition implicate edema as a erroneously non-adipose mass, which may lead to differential assessments of true sarcopenic obesity magnitude by healthcare providers [98,99]. The latter may impact treatment guidelines, graded nutritional counseling, and exercise plans based on an altered perception of phenotype relative to physiological status.…”

Response to “Ultrasonography in Sarcopenic Obesity: ‘Good Looking’ But Wrong Buttoning of the First Button”

“…We thank Kara et al for their response to our article, which we read with great interest 1 . We respectfully disagree with their initial comment that sarcopenia is a regional condition rather than a total fat‐mass condition, as all recent definitions consider sarcopenia as a generalized loss of skeletal muscle mass 2 .…”