Body Composition Monitor Measurements Research Articles

Differences in bioimpedance-derived fluid status between two versions of the Body Composition Monitor

ObjectivesThe Body Composition Monitor (BCM) (Fresenius Medical Care) measures body impedances in alternating currents to subsequently calculate fat and lean tissue mass, fluid compartments, and overhydration (OH). The aim of this study was to investigate differences between two versions of the BCM (an older version, 3.2.5, and a newer version, 3.3.3). MethodsBetween September 2021 and December 2021, 28 hemodialysis patients were included to undergo BCM measurements before each of 14 consecutive dialysis sessions with versions 3.2.5 and 3.3.3 devices. Measurements were performed according to instructions provided by the manufacturer. Differences between BCM devices were tested for statistical significance using paired Wilcoxon tests, neglecting clustering. ResultsA total of 288 measurement pairs of 27 patients were left after exclusion of 43 flawed data points. The mean difference in OH between both BCM devices was 0.548 L (higher for version 3.2.5). Analysis of impedance data revealed differences in the high-frequency spectrum, quantifiable by the intracellular resistance, Ri (median Ri version 3.2.5 = 1750.3 Ω; Ri version 3.3.3 = 1612.45 Ω; P < 0.001), and the time delay, Td (median Td version 3.2.5 = 1.85 ns; Td version 3.3.3 = 8.88 nanoseconds; P < 0.001). ConclusionsThis study finds that results between the two versions of the BCM differed in a clinically meaningful fashion and that the newer version 3.3.3 device had a bias toward less OH. Circulating BCM devices should be checked for versions and only devices of the same version should be used for each patient to ensure better within-patient consistency.

Body composition monitoring in children and adolescents: reproducibility and reference values

There is an increasing need for suitable tools to evaluate body composition in paediatrics. The Body Composition Monitor (BCM) shows promise as a method, but reference values in children are lacking. Twenty children were included and measured twice by 4 different raters to asses inter- and intra-rater reproducibility of the BCM. Reliability was assessed using the Bland-Altman method and by calculating intraclass correlation coefficients (ICCs). The intra-rater ICCs were high (≥ 0.97) for all parameters measured by BCM as were the inter-rater ICCs for all parameters (≥ 0.98) except for overhydration (0.76). Consequently, a study was set up in which BCM measurements were performed in 2058 healthy children aged 3–18.5 years. The age- and gender-specific percentile values and reference curves for body composition (BMI, waist circumference, fat mass and lean tissue mass) and fluid status (extracellular and intracellular water and total body water) relative to age were produced using the GAMLSS method for growth curves.Conclusion: A high reproducibility of BCM measurements was found for fat mass, lean tissue mass, extracellular water and total body water. Reference values for these BCM parameters were calculated in over 2000 children and adolescents aged 3 to 18 years.What is Known• The 4-compartment model is regarded as the ‘gold standard’ of body composition methods, but is inappropriate for regular follow-up or screening of large groups, because of associated limitations.• Body Composition Monitor® is an inexpensive field method that has the potential to be an adequate monitoring tool.What is New• Good reproducibility of BCM measurements in children provides evidence to use the device in longitudinal follow-up, multicentre and comparative studies.• Paediatric reference values relative to age and sex for the various compartments of the body are provided.

Fluid overload is an independent predictor of atrial fibrillation in end-stage renal disease: A prospective study using insertable cardiac and body composition monitors

Fluid overload and atrial fibrillation (AF) are frequently encountered in patients with end-stage renal disease (ESRD). We used subcutaneously insertable cardiac monitors (ICM) to detect AF and associated it with the hydration status, determined with a body composition monitor (BCM) in dialysis patients. 69 patients were recruited. Fluid overload was defined based on BCM measurements as a ratio of overhydration (OH) and extracellular water (OH/ECW) of > 15% at baseline. AF episodes lasting ≥ 2 minutes were collected. 45 in-center hemodialysis patients, 11 on peritoneal dialysis, 12 on home hemodialysis, and 1 predialysis-stage patient were followed up for a median of 2.9 years (25th - 75th percentile 1.9 - 3.1). 29% were overhydrated at baseline, and the percentage remained similar throughout the study. Overhydrated patients had a lower body mass index, a higher prevalence of type 1 diabetes mellitus (DM) and diabetic nephropathy, higher systolic blood pressure, greater ultrafiltration (UF) during dialysis, and a smaller lean tissue index than normohydrated patients. Chronic or paroxysmal AF was known to occur in 20.3% at entry, and a further 33.3% developed AF during the study, with an overall prevalence 53.6%. In univariable logistic regression, OH/ECW > 15% was strongly associated with AF prevalence (OR 6.8, 95% CI 1.7 - 26.5, p = 0.006), as were UF, age, coronary heart disease (CHD), DM, and the echocardiogram-derived ejection fraction and left atrial diameter. In multivariable analyses, OH/ECW > 15% remained an independent predictor of AF alongside age and CHD. The occurrence of AF is independently associated with BCM-measured fluid overload, which is common among ESRD patients.

The Performance of a Body Composition–Based Equation in Estimating Overhydration of Hemodialysis Patients

Achieving and maintaining optimal fluid status remains a major challenge in maintenance hemodialysis (MHD). The aim of this study was to establish a body composition–based multiple regression equation for use in the estimation of overhydration (OH) in the setting of MHD while using a body composition monitor (BCM) to guide patient dry weight management. We initially retrospectively analyzed factors associated with OH in 314 healthy Chinese individuals and obtained a multiple linear regression equation to determine OH level. Next, 49 stable MHD patients were enrolled to validate whether our multiple regression formula was applicable to such patients. Prior to hemodialysis, BCM measurements were performed; OHpre was defined as OH directly measured by BCM; while OHstd was defined as OH estimated by the multiple regression equation. In our multivariate linear regression analysis, PhA (β = − 1.266, 95% CI (− 1.532 ~ − 1.341), p < 0.001), LTM (β = 0.987, 95% CI (0.086 ~ 0.109), p < 0.001), and age (β = − 0.307, 95% CI (− 0.023 ~ − 0.015), p < 0.001) were independent predictors of OH in healthy Chinese individuals. The multiple linear regression equation that we developed for calculating OH was as follows: OHstd = 6.203 − 0.019 × age − 0.083 × gender − 0.006 × fat + 0.098 × LTM − 1.437 × PhA (F = 189.896, R2 = 0.755, p < 0.001). Linear correlation and Bland-Altman analyses were performed between OHpre and OHstd in MHD patients; correlation was found to be high (r = 0.786, p < 0.001). Bias between OHpre and OHstd was 0.45 L as assessed using 95% CI limits of agreement ranging from − 0.73 to 1.62 L. We found that our multiple regression equation formulated using data from healthy individuals provides applicable guidance for dry weight management in MHD patients.

P1466SYSTEMATIC LITERATURE REVIEW OF CLINICAL EVIDENCE FOR THE BODY COMPOSITION MONITOR IN DIALYSIS AND CKD

Abstract Background and Aims The Body Composition Monitor (BCM) is a bioimpedance spectroscopy device to monitor the hydration status of dialysis and CKD patients. NICE (UK) reported only limited evidence on the clinical effectiveness in its Diagnostic Guidance 29. The aim of this work was to provide a structured review of the available evidence up to September 2018 grouped by the most important clinical outcomes (fluid overload, blood pressure, mortality and cardiovascular events). Method MEDLINE, Embase and Cochrane databases were interrogated from 2006 to September 2018. Search and review of identified studies was conducted in compliance with the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results Of 4497 articles identified, 843 were included for full-text review; 424 were full publications and were selected for further analysis. Eight randomized controlled trial (RCT) studies and 150 observational studies met the predefined inclusion criteria; of these, observational studies that recruited at least 100 patients and additionally reported important clinical outcomes such as mortality, cardiovascular (CV) events or hospitalization were selected. Two further RCTs were identified by supplementary searches, giving a total of 10 RCTs (total 2.156 patients) and 41 observational studies (total 168.453 patients) included in this review. The data was grouped by reported outcomes and for each outcome it was analyzed if an effect of BCM-monitored fluid management, or an association between BCM assessment and the respective outcome could be shown. A meta-analysis of the results was not conducted. Reduction of fluid overload RCTs have shown that BCM-monitored fluid management and subsequent alteration of dialysis parameters can lead to effective reduction of fluid overload. Lowering of blood pressure RCTs have indicated that BCM-monitored fluid management can effectively lower blood pressure. Impact on mortality / association with mortality Multiple observational studies have shown a strong association between BCM measurements and mortality. One RCT demonstrated that mortality outcomes can be significantly improved in HD patients with BCM-guided fluid management, while two RCTs reported no significant difference in mortality outcomes. Impact on Cardio Vascular (CV) related events Multiple observational studies have indicated that BCM measurements can predict CV events. One RCT indicated that CV events can be reduced by BCM-monitored fluid management, and two further RCTs indicated that using BCM guidance was at least as good as conventional fluid management. Conclusion There is a strong body of evidence for various important outcomes covering a large patient basis - additional evidence is needed in well designed randomized controlled trials e.g. to demonstrate the effect of reducing BCM determined dehydration.

Validating the use of bioimpedance spectroscopy for assessment of fluid status in children

BackgroundBioimpedance spectroscopy (BIS) with a whole-body model to distinguish excess fluid from major body tissue hydration can provide objective assessment of fluid status. BIS is integrated into the Body Composition Monitor (BCM) and is validated in adults, but not children. This study aimed to (1) assess agreement between BCM-measured total body water (TBW) and a gold standard technique in healthy children, (2) compare TBW_BCM with TBW from Urea Kinetic Modelling (UKM) in haemodialysis children and (3) investigate systematic deviation from zero in measured excess fluid in healthy children across paediatric age range.MethodsTBW_BCM and excess fluid was determined from standard wrist-to-ankle BCM measurement. TBW_D2O was determined from deuterium concentration decline in serial urine samples over 5 days in healthy children. UKM was used to measure body water in children receiving haemodialysis. Agreement between methods was analysed using paired t test and Bland-Altman method comparison.ResultsIn 61 healthy children (6–14 years, 32 male), mean TBW_BCM and TBW_D2O were 21.1 ± 5.6 and 20.5 ± 5.8 L respectively. There was good agreement between TBW_BCM and TBW_D2O (R2 = 0.97). In six haemodialysis children (4–13 years, 4 male), 45 concomitant measurements over 8 months showed good TBW_BCM and TBW_UKM agreement (mean difference − 0.4 L, 2SD = ± 3.0 L). In 634 healthy children (2–17 years, 300 male), BCM-measured overhydration was − 0.1 ± 0.7 L (10–90th percentile − 0.8 to + 0.6 L). There was no correlation between age and OH (p = 0.28).ConclusionsThese results suggest BCM can be used in children as young as 2 years to measure normally hydrated weight and assess fluid status.

Body Composition and Inflammation in Hemodialysis Patients.

The volume state of dialysis patients is important in guiding the dialysis process. Volume overload in these patients is associated with inflammation. The objectives of the present study were to assess the body composition of patients on hemodialysis; to determine the concentrations of B-type natriuretic peptide (BNP) in plasma and evaluate the association of BNP concentrations with volume overload; to determine the concentrations of C-reactive protein (CRP), albumin and superoxide dismutase (SOD) activities as indicators of inflammatory or antioxidant processes. The study included 79 maintenance hemodialysis patients. Assessment of body compartments was carried out using a body composition monitor (BCM). After BCM measurements, blood samples were taken from the patients for laboratory tests. There were 40 (50.6%) volume-overloaded patients (relative overhydration >15%). These patients had a higher prevalence of arterial hypertension (P < 0.05), significantly higher concentrations of BNP (P = 0.01), lower body mass index (P < 0.05) and lower fat tissue index (P < 0.05). There was a positive correlation between plasma BNP and CRP concentrations (ρ = 0.231; P < 0.05), and a negative correlation between (log) BNP and albumin (r = -0.021; P < 0.05), as well as (log) CRP and albumin concentrations (r = -3; P < 0.01). SOD activity was positively correlated with albumin concentrations (r = 0.254; P < 0.05). The concentrations of BNP in this study were associated with volume overload and inflammatory markers. Patients with a higher albumin concentration had higher SOD activity.

Use of the Body Composition Monitor for Fluid Status Measurements in Elderly Malnourished Subjects.

Most hemodialysis (HD) patients are able to finish dialysis at or below the normally hydrated weight determined using the body composition monitor (BCM). However, a minority become symptomatic when they are still fluid overloaded based on BCM-measured overhydration (OH). Malnourished patients frequently fall into this group, suggesting that they may have OH that is inaccessible to ultrafiltration. To isolate any effect of malnutrition on BCM-measured OH from those relating to renal failure, OH measurements for 20 elderly subjects with normal renal function who were classified as malnourished were compared with an age-matched cohort with no known nutritional issues. Body composition monitor measurements were also made on five malnourished HD patients. Mean OH for malnourished subjects with normal renal function was not significantly different from an age-matched cohort without known nutritional deficiencies (1.3 and 1.1 L, respectively; p = 0.5). Post-dialysis OH for HD patients ranged from -0.1 to +4.5 L. A slightly elevated BCM-measured OH appears to be common in elderly subjects and may be explained by changes in the composition of adipose tissue. The effect of malnutrition could not be isolated from sarcopenia, but this study supports the need for caution when reducing target weight in vulnerable patients.

The Body Composition Monitor: a flexible tool for routine fluid management across the haemodialysis population

Bioimpedance measurements with the Body Composition Monitor (BCM) have been shown to improve fluid management in haemodialysis. However, there is a lack of a sufficiently robust evidence-base for use of the BCM outside of standard protocols. This study aims to define the error associated with BCM measurement using alternate paths and timings to allow the use of BCM with confidence in a range of clinical scenarios. BCM measurements were made in 48 healthy controls and in 48 stable haemodialysis patients before and immediately after dialysis. The effect of utilising alternative measurement paths was assessed using mixed effects models and the effect of measuring post-dialysis was assessed by comparing changes in BCM-measured overhydration (OH) with weight changes over dialysis. The data from healthy controls suggest that there is no difference in BCM-measured OH between all the whole-body paths other than the ankle-to-ankle measurement. Dialysis patients showed similar results other than having higher BCM-measured OH when measured across the site of a vascular access. There was good agreement between BCM-measured OH from the standard path and change in weight, suggesting post-dialysis measurements can be utilised. These results suggest BCM protocols can be flexible regarding measurement paths and timing of measurement to ensure as many patients as possible can benefit from the technology.

Volume overload and its risk factors in South African chronic kidney disease patients: an appraisal of bioimpedance spectroscopy and inferior vena cava measurements.

Fluid retention occurs early in chronic kidney disease (CKD) resulting in increased cardiovascular morbidity and mortality. This study aimed to assess volume and nutritional status among South African CKD participants and determine the relationship between malnutrition, inflammation, atherosclerosis, and volume overload using a body composition monitor (BCM). We also evaluated the usefulness of BCM measurement in assessing volume overload. 160 participants comprising hemodialysis, peritoneal dialysis, stage 3 CKD patients, and healthy controls (40 in each group) were studied. A BCM was used to assess fluid and nutritional status. Cardiac dimension measurements, and inferior vena cava diameter (IVCD) and carotid intima media thickness were assessed by echocardiography and ultrasonography, respectively. Serum interleukin-6 (IL-6) and C-reactive protein (CRP) levels were measured as markers of inflammation. Fluid overload and malnutrition were present in 68% and 63% of studied patients, respectively. Using physical examination findings as the reference measurements for volume overload, the area under the concentration curves for BCM and IVCD measurements were 0.866 (sensitivity 82%, specificity 74%, p < 0.001) and 0.727 (sensitivity 57%, specificity 70%, p < 0.001), respectively. Lean tissue index, inflammation, and atherosclerosis were associated with volume overload. Volume overload and malnutrition were common across the spectrum of South African CKD cohorts; volume overload was associated with malnutrition, inflammation, and atherosclerosis. Bioimpedance spectroscopy (BIS) is a useful and sensitive tool for the assessment of fluid status in clinically euvolumic nondialytic CKD patients.

Use of the Body Composition Monitor for Fluid Status Measurements in Subjects with High Body Mass Index

Background: Fluid management is a central aspect of haemodialysis (HD). Body composition monitor (BCM)-measured overhydration (OH) can improve fluid management strategies, but there remains uncertainty about its use in subjects with high body mass index (BMI). This study explored whether the observed tendency for HD patients with high BMI to complete dialysis fluid depleted according to BCM is associated with an artefact in the BCM models, or with systematic differences in the prescription and delivery of treatment. Methods: To isolate the effect of BMI from effects relating to treatment, BCM measurements were made on 20 healthy subjects with high BMI. Mean OH was compared with a previously reported cohort of healthy subjects with normal BMI. To further explore BCM-measured OH in HD patients, measurements were made pre- and post-dialysis on 10 patients with high BMI alongside relative blood volume monitoring. Body shape was classified to assess associations between shape and OH. Results: The mean OH for healthy subjects with high BMI was -0.1 litres, which was not different from that of healthy subjects with normal BMI. Median BCM-measured OH for HD patients was 1.8 and -1.8 litres pre- and post-dialysis respectively, while blood volume and blood pressure were maintained. Body shape correlated with OH in control subjects but not HD patients. Conclusions: We found no evidence of systematic bias in BCM-measured OH with high BMI in healthy subjects. BCM-measured post-dialysis fluid depletion in asymptomatic patients with high BMI appears to result from greater tolerance of ultrafiltration and ability to maintain blood volume.

Is overhydration in peritoneal dialysis patients associated with cardiac mortality that might be reversible?

To study the relationship between overhydration (OH) in peritoneal dialysis (PD) patients and cardiac mortality. OH, as measured by body composition monitor (BCM), is associated with increased mortality in dialysis patients. BCM has been used to guide treatment on the assumption that correcting OH will improve cardiac morbidity and mortality although data demonstrating causality that is reversible is limited. We wished to determine if OH in PD patients predicted cardiac mortality, and if there was a correlation between OH and cardiac troponin-T (cTnT) levels. Finally, we wished to determine if improving OH values would lead to a decrement in cTnT. All prevalent PD patients over the study period of 57 mo who had contemporaneous BCM and cTnT measurements were followed irrespective of transplantation or PD technique failure. We also studied a cohort of patients with who had severe OH (> +2L). The Fresenius Body Composition Monitor was used to obtain hydration parameters. cTnT levels were done as part of routine clinical care. Data was analysed using SPSS version 20.0. There were 48 deaths in the 336 patients. The patients that died from cardiac or non-cardiac causes were similar with respect to their age, incidence of diabetes mellitus, gender, ethnicity and cause of renal failure. However, the patients with cardiac causes of death had significantly shorter dialysis vintage (10.3 mo vs 37.0 mo, P < 0.0001) and were significantly more overhydrated by BCM measurement (2.95 L vs 1.35 L, P < 0.05). The mean (standard error of the means) hydration status of the 336 patients was +1.15 (0.12) L and the median [interquartile range (IQR)] cTnT level was 43.5 (20-90) ng/L. The cTnT results were not normally distributed and were therefore transformed logarithmically. There was a statistically significant correlation between Log (cTnT) with the OH value (Spearman r value 0.425, P < 0.0001). We identified a sub-group of patients that were severely overhydrated; median (IQR) hydration at baseline was +2.7 (2.3 to 3.7) L. They were followed up for a minimum of 6 mo. Reduction in OH values in these patients over 6 mo correlated with lowering of cTnT levels (Spearman r value 0.29, P < 0.02). Patients that were overhydrated had higher cTnT, and had deaths that were more likely to be cardiac related. Reduction in OH correlated with lowering of cTnT.

Baseline hydration status in incident peritoneal dialysis patients: the initiative of patient outcomes in dialysis (IPOD-PD study)†.

BackgroundNon-euvolaemia in peritoneal dialysis (PD) patients is associated with elevated mortality risk. There is an urgent need to collect data to help us understand the association between clinical practices and hydration and nutritional status, and their effects on patient outcome.MethodsThe aim of this prospective international, longitudinal observational cohort study is to follow up the hydration and nutritional status, as measured by bioimpedance spectroscopy using the body composition monitor (BCM) of incident PD patients for up to 5 years. Measures of hydration and nutritional status and of clinical, biochemical and therapy-related data are collected directly before start of PD treatment, at 1 and 3 months, and then every 3 months. This paper presents the protocol and a pre-specified analysis of baseline data of the cohort.ResultsA total of 1092 patients (58.1% male, 58.0 ± 15.3 years) from 135 centres in 32 countries were included. Median fluid overload (FO) was 2.0 L (males) and 0.9 L (females). Less than half of the patients were normohydrated (38.7%), whereas FO > 1.1 L was seen in 56.5%. Systolic and diastolic blood pressure were 139.5 ± 21.8 and 80.0 ± 12.8 mmHg, respectively, and 25.1% of patients had congestive heart failure [New York Heart Association (NYHA) 1 or higher]. A substantial number of patients judged to be not overhydrated on clinical judgement appeared to be overhydrated by BCM measurement. Overhydration at baseline was independently associated with male gender and diabetic status.ConclusionsThe majority of patients starting on PD are overhydrated already at start of PD. This may have important consequences on clinical outcomes and preservation of residual renal function. Substantial reclassification of hydration status by BCM versus on a clinical basis was necessary, especially in patients who were not overtly overhydrated. Both clinical appreciation and bioimpedance should be combined in clinical decision-making on hydration status.

New reliable methods for the diagnose of protein-energy wasting in hemodialysis patients

Protein-energy wasting (PEW), defined as the body loss of muscle mass and fat, is an important cardiovascular risk factor in dialysis patients. Diagnosing this condition requires the presence of three characteristics: biochemical (low albumine, prealbumine or cholesterol), body mass reduction (body mass index, weight loss or fat loss) and muscle mass reduction (measured by means of creatinine or arm muscle area). This study aimed at demonstrating that the lean tissue index (LTI) calculated by spectroscopic bioimpedance (SBI) is a valid parameter for the diagnostic of protein-energy wasting. Cross-sectional study including 1369 patients with two BCM measurements on a six-month delay, analyzing analytic and spectroscopic bioimpedance parameters. The lean tissue index from the BCM (Body Composition Monitor) quantifies the patient's lean mass and it is matched against traditional parameters (plasma albumine) and non-traditional parameters (IRE and PCR) for protein-energy wasting with no alterations from the patient's hydration level. LTI is an easy to obtain parameter of lean mass which can be followed and monitored in order to diagnose risk situations of our patients as it is the protein- energy wasting.