Dual Energy X-ray Absorptiometry and Bioimpedance Analysis are Clinically Useful for Measuring Muscle Mass in Kidney Transplant Recipients With Sarcopenia.

Computed tomography (CT) is considered the gold standard method for the diagnosis and characterization of sarcopenia. The aim of the present study was to determine the correlation between the volume of psoas muscle measured using CT and the measurement of muscle mass with dual energy X-ray absorptiometry (DXA) and bioimpedance analysis (BIA) in kidney transplant recipients. Fifty-eight recipients (42 males and 16 females) were enrolled. Diagnostic criteria for sarcopenia were according to those of the Asia Working Group for Sarcopenia. The volume of psoas muscle was extracted using image recognition software from three-dimensional CT images. The volume of psoas muscle was 227.2 ± 61.3 mL in Group 1 (sarcopenia), 283.9 ± 75.3 mL in Group 2 (presarcopenia), and 363.7 ± 138.0 mL in Group 3 (without sarcopenia). Muscle mass measured using DXA was 15.80 ± 3.19 kg in Group 1, 16.36 ± 2.49 kg in Group 2, and 21.21 ± 4.14 kg in Group 3. Additionally, muscle mass assessed using BIA was 17.22 ± 4.11 kg in Group 1, 17.86 ± 3.30 kg in Group 2, and 21.48 ± 5.39 kg in Group 3. There were significant differences in the mean volume of psoas muscle between the 3 groups. There was a significant positive correlation between the volume of psoas muscle and the muscle mass assessed using DXA (r = 0.797; P < .001) and BIA (r = 0.761; P < .001). Furthermore, there was a significant positive correlation between DXA and BIA (r = 0.900; P < .001). It was suggested that estimating muscle mass using DXA and BIA is a preferred method for diagnosis of sarcopenia in kidney transplant recipients.

Yanishi M ，Kinoshita H ，Tsukaguchi H ，Kimura Y ，Koito Y ，Jino E ，Watanabe M ，Sugi M ，Matsuda T ... -  《-》

Case finding for sarcopenia in geriatric inpatients: performance of bioimpedance analysis in comparison to dual X-ray absorptiometry.

Reiss J ，Iglseder B ，Kreutzer M ，Weilbuchner I ，Treschnitzer W ，Kässmann H ，Pirich C ，Reiter R ... -  《BMC Geriatrics》

Diagnosis of sarcopenia by evaluating skeletal muscle mass by adjusted bioimpedance analysis validated with dual-energy X-ray absorptiometry.

This study aimed to adjust and cross-validate skeletal muscle mass measurements between bioimpedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) for the screening of sarcopenia in the community and to estimate the prevalence of sarcopenia in Hong Kong. Screening of sarcopenia was provided to community-dwelling older adults. Appendicular skeletal muscle mass (ASM) was evaluated by BIA (InBody 120 or 720) and/or DXA. Handgrip strength and/or gait speed were assessed. Diagnosis of sarcopenia was based on the 2019 revised Asian Working Group for Sarcopenia cut-offs. Agreement analysis was performed to cross-validate ASM measurements by BIA and DXA. Multiple regression was used to explore contribution of measured parameters in predicting DXA ASM from BIA. A total of 1587 participants (age = 72 ± 12 years) were recruited; 1065 participants were screened by BIA (InBody 120) with 18 followed up by DXA, while the remaining 522 participants were assessed by the BIA (InBody 720) and DXA. The appendicular skeletal muscle mass index (ASMI) evaluated by BIA showed a mean difference of 2.89 ± 0.38 kg/m2 (InBody 120) and 2.97 ± 0.45 kg/m2 (InBody 720) against DXA gold standard. A significant overestimation of muscle mass was measured by BIA compared with DXA (P < 0.005). BIA data were adjusted using prediction equation and mean difference reduced to -0.02 ± 0.31 kg/m2 in cross-validation. Prevalence of sarcopenia in older adults ≥65 ranged from 39.4% (based on ASMI by DXA) to 40.8% (based on predicted DXA ASMI from BIA). Low ASMI by DXA was found in 68.5% of the older adults screened. The percentage of older adults exhibited low handgrip strength ranged from 31.3% to 56%, while 49% showed low gait speed. Bioimpedance analysis was found to overestimate skeletal muscle mass compared with DXA. With adjustment equations, BIA can be used as a quick and reliable tool for screening sarcopenia in community and clinical settings with limited access to better options.

Cheng KY ，Chow SK ，Hung VW ，Wong CH ，Wong RM ，Tsang CS ，Kwok T ，Cheung WH ... -  《-》

Accuracy of surrogate methods to estimate skeletal muscle mass in non-dialysis dependent patients with chronic kidney disease and in kidney transplant recipients.

Bioelectrical impedance analysis (BIA) and anthropometric predictive equations have been proposed to estimate whole-body (SMM) and appendicular skeletal muscle mass (ASM) as surrogate for dual energy X-ray absorptiometry (DXA) in distinct population groups. However, their accuracy in estimating body composition in non-dialysis dependent patients with chronic kidney disease (NDD-CKD) and kidney transplant recipients (KTR) is unknown. The aim of this study was to investigate the accuracy and reproducibility of BIA and anthropometric predictive equations in estimating SMM and ASM compared to DXA, in NDD-CKD patients and KTR. A cross-sectional study including adult NDD-CKD patients and KTR, with body mass index (BMI) ≥18.5 kg/m2. ASM and estimated SMM were evaluated by DXA, BIA (Janssen, Kyle and MacDonald equations) and anthropometry (Lee and Baumgartner equations). Low muscle mass (LowMM) was defined according to cutoffs proposed by guidelines for ASM, ASM/height2 and ASM/BMI. The best performing equation as surrogate for DXA, considering both groups of studied patients, was defined based in the highest Lin's concordance correlation coefficient (CCC) value, the lowest Bland-Altman bias (<1.5 kg) combined with the narrowest upper and lower limits of agreement (LoA), and the highest Cohen's kappa values for the low muscle mass diagnosis. Studied groups comprised NDD-CKD patients (n = 321: males = 55.1%; 65.4 ± 13.1 years; eGFR = 28.8 ± 12.7 ml/min) and KTR (n = 200: males = 57.7%; 47.5 ± 11.3 years; eGFR = 54.7 ± 20.7 ml/min). In both groups, the predictive equations presenting the best accuracy compared to DXA were SMM-BIA-Janssen (NDD-CKD patients: CCC = 0.88, 95%CI = 0.83-0.92; bias = 0.0 kg; KTR: CCC = 0.89, 95%CI = 0.86-0.92, bias = -1.2 kg) and ASM-BIA-Kyle (NDD-CKD patients: CCC = 0.87, 95%CI = 0.82-0.90, bias = 0.7 kg; KTR: CCC = 0.89, 95%CI = 0.86-0.92, bias = -0.8 kg). In NDD-CKD patients and KTR, LowMM frequency was similar according to ASM-BIA-Kyle versus ASM-DXA. The reproducibility and inter-agreement to diagnose LowMM using ASM/height2 and ASM/BMI estimated by BIA-Kyle equation versus DXA was moderate (kappa: 0.41-0.60), in both groups. Whereas female patients showed higher inter-agreement (AUC>80%) when ASM/BMI index was used, male patients presented higher AUC (70-74%; slightly <80%) for ASM/height2 index. The predictive equations with best performance to assess muscle mass in both NDD-CKD patients and KTR was SMM-BIA by Janssen and ASM-BIA by Kyle. The reproducibility to diagnose low muscle mass, comparing BIA with DXA, was high using ASM/BMI in females and ASM/height2 in males in both groups.

Barreto Silva MI ，Menna Barreto APM ，Pontes KSDS ，Costa MSD ，Rosina KTC ，Souza E ，Bregman R ，Prado CM ，Klein MRST ... -  《-》

Quantifying appendicular muscle mass in geriatric inpatients: Performance of different single frequency BIA equations in comparison to dual X-ray absorptiometry.

Quantification of skeletal muscle mass is mandatory for diagnosing sarcopenia, a highly prevalent geriatric syndrome. While dual energy X-ray absorptiometry (DXA) is the reference method in a clinical context, bioimpedance analysis (BIA) is more readily applicable on a broad scale. Recently BIA equations for the prediction of appendicular skeletal muscle mass in higher age groups have been published, but data on their performance in geriatric inpatients are lacking. In 144 geriatric inpatients (86 women and 58 men, mean age 80.7 ± 5.6 years) appendicular skeletal muscle mass was predicted by 4 different BIA equations and measured by DXA. Results were compared by linear regression analysis and Bland Altmann plots. The agreement with DXA in classifying subjects to have normal or reduced muscle mass was calculated for the BIA based approaches. The 4 BIA equations showed only minor differences in regression analysis, but major differences in mean error (range -0.98 kg to + 0.19 kg in women and -2.47 kg to -0.58 kg in men). Considering regression parameters and mean error, the equation of Scafoglieri et al. performed best, resulting in an agreement with DXA of more than 83%. Sensitivity to detect subjects with reduced muscle mass was <70% in the whole group for all BIA equations. The BIA equation of Scafoglieri et al. performs best in geriatric inpatients, with more than 83% of subjects classified correctly as having normal or reduced muscle mass compared to DXA. Low sensitivity to detect subjects with reduced muscle mass in geriatric inpatients remains a limitation of BIA.

Reiter R ，Iglseder B ，Treschnitzer W ，Alzner R ，Mayr-Pirker B ，Kreutzer M ，Pirich C ，Kässmann H ，Dovjak P ，Reiss J ... -  《-》