Estimation of Muscle Mass in the Integrated Assessment of Patients on Hemodialysis

Assessment of muscle mass (MM) or its proxies, lean tissue mass (LTM) or fat-free mass (FFM), is an integral part of the diagnosis of protein-energy wasting (PEW) and sarcopenia in patients on hemodialysis (HD). Both sarcopenia and PEW are related to a loss of functionality and also increased morbidity and mortality in this patient population. However, loss of MM is a part of a wider spectrum, including inflammation and fluid overload. As both sarcopenia and PEW are amendable to treatment, estimation of MM regularly is therefore of major clinical relevance. Whereas, computer-assisted tomography (CT) or dual-energy X-ray absorptiometry (DXA) is considered a reference method, it is unsuitable as a method for routine clinical monitoring. In this review, different bedside methods to estimate MM or its proxies in patients on HD will be discussed, with emphasis on biochemical methods, simplified creatinine index (SCI), bioimpedance spectroscopy (BIS), and muscle ultrasound (US). Body composition parameters of all methods are related to the outcome and appear relevant in clinical practice. The US is the only parameter by which muscle dimensions are measured. BIS and SCI are also dependent on either theoretical assumptions or the use of population-specific regression equations. Potential caveats of the methods are that SCI can be influenced by residual renal function, BIS can be influenced by fluid overload, although the latter may be circumvented by the use of a three-compartment model, and that muscle US reflects regional and not whole body MM. In conclusion, both SCI and BIS as well as muscle US are all valuable methods that can be applied for bedside nutritional assessment in patients on HD and appear suitable for routine follow-up. The choice for either method depends on local preferences. However, estimation of MM or its proxies should always be part of a multidimensional assessment of the patient followed by a personalized treatment strategy

Estimating thigh skeletal muscle volume using multi-frequency segmental-bioelectrical impedance analysis

A Correction to this article was published on 13 December 2021BACKGROUND: The primary aim of this study was to investigate whether using the extracellular water/intracellular water (ECW/ICW) index and phase angle combined with segmental-bioimpedance analysis (BIA) improved the model fitting of skeletal muscle volume (SMV) estimation. The secondary aim was to compare the accuracy of segmental-BIA with that of ultrasound for estimating the quadriceps SMV measured with MRI. METHODS: Seventeen young men (mean age, 23.8 ± 3.3 years) participated in the study. The T-1 weighted images of thigh muscles were obtained using a 1.5 T magnetic resonance imaging (MRI) scanner. Thigh and quadriceps SMVs were calculated as the sum of the products of anatomical cross-sectional area and slice thickness of 6 mm across all slices. Segmental-BIA was applied to the thigh region, and data on the 50-kHz bioelectrical impedance (BI) index, ICW index, ECW/ICW index, and phase angle were obtained. The muscle thickness index was calculated as the product of the mid-thigh muscle thickness, determined using ultrasound, and thigh length. The standard error of estimate (SEE) of the regression equation was calculated to determine the model fitting of SMV estimation and converted to %SEE by dividing the SEE values by the mean SMV. RESULTS: Multiple regression analysis indicated that the combination of 50-kHz BI and the ECW/ICW index or phase angle was a significant predictor when estimating thigh SMV (SEE = 7.9 and 8.1%, respectively), but were lower than the simple linear regression (SEE = 9.4%). The ICW index alone improved the model fitting for the estimation equation (SEE = 7.6%). The model fitting of the quadriceps SMV with the 50-kHz BI or ICW index was similar to that with the skeletal muscle thickness index measured using ultrasound (SEE = 10.8, 9.6 and 9.7%, respectively). CONCLUSIONS: Combining the traditionally used 50-kHz BI index with the ECW/ICW index and phase angle can improve the model fitting of estimated SMV measured with MRI. We also showed that the model suitability of SMV estimation using segmental-BIA was equivalent to that on using ultrasound. These data indicate that segmental-BIA may be a useful and cost-effective alternative to the gold standard MRI for estimating SMV

Strength, water compartments and phase angle in breast cancer survivors

Background: Accurate prognostic tools are determinant for decision-making in cancer care planning. Objective measures such as bioelectrical impedance spectroscopy (BIS) may improve the accuracy of prognostic. In this cross-sectional study the goal was to determine if the water compartments and the phase angle were predictors of muscular strength in breast cancer survivors (BCS). Methods: A total of 41 BCS (age 54.6 ± 9.2) were evaluated. Water compartments and phase angle were assessed with BIS and muscular strength was assessed with handgrip dynamometer. Moderate-to-vigorous physical activity (MVPA) was assessed using the International Physical Activity Questionnaire (IPAQ). Measurements were performed in the morning after an overnight feast. Results: Linear regression analysis showed that phase angle explained 22% (r2 = 0.216) of the variance of the handgrip. Independently of MVPA and time post-operation, phase angle remained a significant predictor (B=2.269, p=0.085). No associations were found between water compartments and handgrip strength (p>0.05). Conclusions: The findings of this study suggest that phase angle is an important predictor of muscular strength in breast cancer survivors.Introdução: É necessário definir medidas de prognóstico precisas para que haja uma melhor tomada de decisão relativamente ao planeamento do tratamento de cancro da mama. Medidas objetivas como a bioimpedância elétrica multiespectral (BIS) podem melhorar a precisão de prognóstico. Neste estudo transversal o objetivo será determinar se os compartimentos hídricos e o ângulo de fase são preditores da força muscular em sobreviventes de cancro da mama. Métodos: A amostra consistiu em 41 sobreviventes de cancro da mama (idade 54.6 ± 9.2 anos). Os compartimentos hídricos e o ângulo de fase foram medidos com a BIS e a força muscular com um dinamómetro. A atividade física moderada a vigorosa (MVPA) foi avaliada através do Questionário Internacional de Atividade Física (IPAQ). As medições foram realizadas durante a manhã com os participantes em jejum. Resultados: A análise da regressão linear mostra que o ângulo de fase explica 22% (r2 = 0.216) da variação da força muscular. Independentemente da MVPA e tempo pós-operatório, o ângulo de fase manteve-se um preditor significativo (B=2.269, p=0.085). Não foram encontradas associações entre os compartimentos hídricos e força muscular (p>0.05). Conclusão: Os resultados deste estudo sugerem que o ângulo de fase é um importante preditor da força muscular em sobreviventes de cancro da mama

Bioimpedance as a predictor of survival in renal failure and associated comorbidities.

Background: Renal failure requiring dialysis is associated with a high mortality. One of the contributing causes is overhydration. Overhydration can be assessed by bioimpedance analysis (BIA)– the non-invasive electrical measure of small current through the tissues that estimates the proportion of fluid that is intracellular water (ICW, typically muscle which is healthy) and extracellular (ECW, which in excess causes tissue oedema and is potentially dangerous). Several studies indicate that a extracellular water to total body water (TBW) ratio is associated with increased risk of death in dialysis patients but it is not clear if this is independent of other risk factors for death, namely comorbidity. Aims and objectives: To establish the prognostic value of BIA in the prediction of survival on dialysis in the context of other known predictors of survival or hospitalisation. With further analysis of the applicability of the same scenario to heart failure patients. Methodology: To conduct a systematic review using a standardised approach including a prespecified research question, search terms and criteria for study inclusion. With independent selection for inclusion in the study and quality appraisal by multiple authors with different backgrounds and experience. Results: 2701 studies identified by literature search, plus an additional 4 through reference checking. 38 papers included in final analysis, 4 of which were regarding heart failure cohorts. Analysis of the research shows that BIA is an independent predictor of mortality. Conclusion: BIA shown to be an independent predictor of mortality in dialysis patients, further research needed to extrapolate to heart failure (HF) populations

A portable bioimpedance spectroscopy system for congestive heart failure management

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 139-149).Congestive Heart Failure (CHF) is a chronic medical condition that causes reduced exercise tolerance, shortness of breath, and fluid buildup in the lungs, legs, and abdomen. While CHF-related mortality has reduced in recent years, this reduction has been accompanied by an increase in hospitalizations and readmissions. This thesis takes the first steps toward developing a compression sock based bioimpedance monitoring system for patients with CHF to help reduce readmission rates. The primary goals of the thesis were to better understand the calf bioimpedance measurement in a controlled environment (hemodialysis) and to develop portable hardware to perform measurements. Calf bioimpedance was measured on 17 patients undergoing hemodialysis using both a commercial measurement system and the experimental system developed in this thesis. Measured calf bioimpedance data showed that more fluid is recruited from the calf at higher ultrafiltration rates. Fluid shifts into or out of cells also depended on the ultrafiltration rate. It was also observed that patients with high calf fluid overload accumulate fluid in the calf, rather than lose it. Bioimpedance measurements were also compared between the side of the leg and back of the leg. Changes in calf bioimpedance were higher on the back in 4/7 patients measured, suggesting that ideal electrode placement depends on the individual patient. Finally, a portable bioimpedance system was developed and verified against a commercial system on the bench and during hemodialysis. The two systems measured bioimpedance changes within 2 in most cases, with outliers limited to patients with particularly low calf bioimpedance. While the relationship between calf fluid status and total fluid status is complex, there is likely utility in calf bioimpedance measurements for CHF remote monitoring. In the ideal use case, patients will start out at dry weight and gain comparable amounts of fluid compared with the fluid removed during hemodialysis. This should result in measurable calf bioimpedance changes on the same order of those measured here. Additionally, rates of both fluid accumulation and removal will be an order of magnitude slower than hemodialysis, so volume compartments should be in equilibrium, unlike immediately following hemodialysis as was measured in this thesis.by Maggie Delano.Ph. D

Validity of Body Composition Assessment in Racial and Ethnic Minority Populations

Few investigations have evaluated the validity of up-to-date body composition technology across diverse populations. Due to the relationship between obesity and cardiometabolic disease risk, it is vital to measure body composition accurately. The overall purpose of the proposed study was to assess the validity of multiple body composition assessments utilizing a four-compartment model criterion within a multi-ethnic sample stratified by race/ethnicity. One hundred and ten individuals (55% female, Age: 26.5 ± 6.9, body fat percentage [%fat]: 25.7 ± 9.5%) identifying as Asian (n=22), African American/Black (n=22), Caucasian/White (n=22), Hispanic (n=22), Multi-racial (n=21) and Native American (n=1) were enrolled in the present study. Eight body composition models were evaluated including dual energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), two bioelectrical impedance devices (BIS, IB) and four multi-compartment models (BIS 4C, BIS 3C, deuterium dilution 3C, DXA-body volume [BV] 4C) which utilized a combination of the single device estimates to measure body composition (%fat, fat-free mass [FFM]). For the total multi-ethnic sample, measures of %fat and FFM from multi-compartment models were all excellent to ideal (%fat: TE=0.94–2.37%; FFM: TE=0.72–1.78 kg), with the exception of the DXA-BV 4C model, which was good to fairly good for %fat (TE=3.79%). For the single device models, %fat measures were very good to excellent for DXA, ADP and IB (TE=2.52-2.89%) and fairly good for BIS (TE=4.12%). For FFM, single device estimates were very good to ideal. Results did not vary significantly between races/ethnicities. The current study results suggests the multi-compartment models evaluated can be utilized in a multi-ethnic sample, as well as in each individual race/ethnicity to obtain highly valid results for both %fat and FFM. Additionally, the single device estimates from DXA, ADP and IB are valid for mean estimates. The BIS may not be valid for estimates in African American/Black, Caucasian/White and Multi-racial samples. Investigators and clinicians can accurately estimate body composition in minority populations utilizing the devices evaluated in the present study, however, BIS results should be interpreted cautiously.Doctor of Philosoph

The Effect of Diffusive and Convective Sodium Balance During Hemodialysis on Interdialytic Weight Gain

Patients with end stage renal disease (ESRD) often require hemodialysis treatments in which blood’s water and dissolved solutes undergo diffusion and convection by exposure to an extracorporeal membrane. The leading cause of death in this population is cardiovascular, and how hemodialysis is prescribed alters total sodium balance, a critical determinant of cardiovascular health. We performed retrospective and prospective analysis of data from patients in the Southwestern Ontario Regional Hemodialysis Program. An increased Dialysate sodium (Dial-Na+) to Pre-dialysis plasma sodium (Pre- Na+) concentration difference (DPNa+) leads to adverse clinical outcomes in hemodialysis patients. The post- to pre-dialysis plasma sodium difference (PPNa+) predicts clinical outcomes equally well as DPNa+ so long as Dial-Na+ is within 3 mmol/L of Pre-Na+. Calculation of DPNa+ requires determination of the Pre-Na+, historically thought to be stable in hemodialysis patients and thus termed “setpoint” (SP). However, we determined that SP is modifiable by hemodialysis prescription. Finally, an equation to predict interdialytic weight gain was created, confirming Dial-Na+, dialysis frequency and duration to be modifiable factors affecting IDWG. Further research is required to validate this equation prospectively, and to determine the impact of changes of SP on cardiovascular morbidity and mortality

Effect of fluid loss following hemodialysis on tibialis anterior muscle strength in people with end-stage renal disease

ABSTRACT PURPOSE: The purpose of this study was to evaluate the effect of fluid loss following hemodialysis (HD) on tibialis anterior (TA) strength in participants with end-stage renal disease. Issues concerning measures of skeletal muscle hydration and efficacy of exercise as an anabolic intervention were also addressed. METHODS: Data from published literature were combined in a meta-analysis to establish efficacy of exercise in participants on HD. Three clinical studies were undertaken using data acquired from healthy volunteers and participants on HD. Hydration of the calf muscles was estimated using bioelectrical impedance spectroscopy (BIS) [extracellular (ECF) and intracellular (ICF) fluid] and magnetic resonance imaging (MRI) [transverse relaxation time constants (T2) and apparent diffusion coefficient (ADC)] acquired measures. Reliabilities and associations between the measures acquired using these two techniques were established using intraclass correlations and linear regression analyses. The maximal voluntary isometric contraction (MVIC) strength of TA was measured using a dynamometer. RESULTS: A significant reduction (p2 shortened by 2.38ms; 95%CI: 1.04, 3.71) of TA, and calf ICF by 0.05 liters (95%CI: 0.01, 0.08) were observed between before and after HD measurements. In comparison with control group, participants on HD had significantly (p2 of TA was significantly (p2 of TA (β = 0.44, p=0.042), medial gastrocnemius (β = 0.47, p=0.027) and ADC of lateral gastrocnemius (β = 0.6, p= 0.003) after HD only; hence these measures could not be used interchangeably as measures of TA interstitial fluid. CONCLUSION:We observed reduction in strength (~6%) and volume (~ 15%) of TA following HD. Further research is required to evaluate the impact of myocellular lipids and muscle architecture on estimates of ECF and MVIC of TA for establishing absolute or relative effects of fluid loss on TA muscle volume and strength