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Introduction Fluid management is an important goal of dialysis treatment. The accurate assessment of fluid status is still a challenge for clinical nephrologists. Bioimpedance analysis (BIA) has been proposed as an objective tool to assess hydration. Methods This was a prospective randomized controlled study to compare hydration status measured by clinical assessment compared to BIA using a body composition monitor (BCM). The primary outcome was defined as the decline of cardiac biomarker N-terminal pro brain natriuretic peptide (NT-proBNP) from baseline to the end of the study. Findings About 281 chronic hemodialysis patients were assessed for eligibility, and 132 patients provided written informed consent to participate (65 BIA group, 67 clinical group). Predialytic NT-proBNP, and decline of NT-proBNP were similar in both groups. The amount of overhydration (2.18 ± 2.11 L vs. 1.29 ± 1.97 L; p 0.016) and the number of patients with severe overhydration (46.0% vs. 30.6%, p = 0.04) were significantly higher in the BIA group at the end of the study. Fluid accumulation in the interdialytic period was significantly lower in the clinical group (p = 0.013). Adverse events occurred more often in the BIA group (p = 0.032). The cumulative number of hypovolemic events was significantly higher in the BIA group (p = 0.002). Discussion Fluid management by BIA does not lead to a better cardiac outcome (appraised by surrogate markers) than fluid management by careful clinical assessment. Adapting the dry weight according to BIA results increases the risk of adverse events, especially hypovolemic episodes. Careful clinical fluid assessment is important for optimal care of chronic hemodialysis patients.

Background Nutrition imbalance is common in chronic kidney disease (CKD) children. This study evaluated the nutrition status of CKD children at different stages using bioimpedance analysis (BIA) compared with anthropometry. Methods Fifty-five CKD children at stages III, IV, V and 19 age- and sex-matched healthy controls were recruited. Fat, protein and mineral composition on BIA were analyzed together with anthropometry for height, weight and body mass index (BMI). Biochemistry was also checked in CKD children. Results Of the CKD children, 23.6%, 10.9% and 56.3% were underweight, overweight/obese and stunted, respectively. On BIA, 52.7%, 70.9%, 14.5% and 40.0% of the CKD children had protein reduction, fat reduction, fat enhancement and mineral reduction, respectively. Growth retardation and nutrition reduction became remarkable at stages IV and V. Approximately 65% of healthy-weight children had nutrition reduction. In the underweight and healthy-weight groups, fat reduction rates were higher than protein reduction rate. In the overweight/obese group, fat enhancement was most notable. Mineral reduction was less remarkable. Conclusions The nutrition imbalance in CKD children on BIA correlated well with anthropometry and disease process, supporting BIA as an auxiliary diagnosis tool.

Aim Bioelectrical impedance analysis is a promising method in determining the body compartments in hemodialysis patients. In this study, we aimed to investigate the agreement between two widely used methods: the single-frequency and multi-frequency bioelectrical impedance analyses. Methods Maintenance hemodialysis patients were enrolled in the study. Single-frequency and multi-frequency bioelectrical impedance analyses were performed consecutively before hemodialysis. A second bioelectrical impedance analysis was performed right after the hemodialysis session. A third bioelectrical impedance analysis was performed one hour after hemodialysis. We used weight change as a measure of fluid removal during hemodialysis session. Results Bioelectrical impedance analysis estimates from both devices had significant differences. Best agreement was observed between single frequency and multifrequency device at the immediate post hemodialysis extracellular water estimates (mean difference 0,076 L). We found the best agreement between weight change and extracellular water change using single-frequency bioimpedance analysis. Moreover, one hour waiting time did not improve the agreement between weight and extracellular water changes for both devices. Different estimates seem to be caused by different raw impedance data measured by both devices and device specific equations. Conclusion There are significant differences among bioelectrical impedance measurements performed with different bioelectrical impedance analyzers. Using open source software might be an important step forward in the development of standardized measurements.

Summary Heart rate variability (HRV) is altered in obese subjects, but whether this is true also in underweight (UW) subjects is still under debate. We investigated the HRV profile in a sample of healthy adult women and its association with adiposity. Five-minute resting state electrocardiographic activity was recorded in 69 subjects grouped according to their body mass index, [23 normal weight (NW), 23 overweight/obese (OW) and 23 UW). Body fat mass (FM) was measured by bio-impedance. Frequency- and time-domain analyses were performed. Compared to NW, UW and OW subjects showed a significant decrease in HRV indices, as revealed by spectral analysis. No differences were observed between UW and OW subjects. A second-order polynomial regression unveiled an inverted U-shaped relationship between FM extent and HRV indices. A decrease of HRV indices was associated with changes in FM extent, proving that in UW and OW subjects, the adaptive flexibility of autonomic cardiac function was reduced. These findings provide important clues to guide future studies addressed to determine how changes in adiposity and autonomic cardiac function may contribute to health risk.

Aim Studies in animals show a relationship between extracellular volume and gastrointestinal motility. End-stage renal disease (ESRD) patients present fluid overload and frequent dyspeptic symptoms. We looked for an association between volaemic status and dyspepsia among ESRD patients undergoing haemodialysis (HD). Methods We studied 155 ESRD patients on HD. Their volaemic status was evaluated using bioimpedance analysis. Fluid overload (FO) in litres and relative fluid overload (rFO) in percentage were calculated. rFO > 15% was classified as hypervolaemia. Dyspepsia was assessed through the Porto Alegre Dyspeptic Symptoms Questionnaire (PADYQ). PADYQ scores equal to or greater than 6 classified patients as dyspeptic. Characteristics of patients with and without dyspepsia were compared. Pearson's test was used to test the correlation between continuous variables. Multivariate linear and logistic regressions were performed to test FO as predictor of dyspepsia score and the presence of dyspepsia. Results There were 64 (41.2%) patients with dyspepsia. Dyspeptics presented higher FO (2.5 ± 1.8 L vs 1.0 ± 1.8 L; P

The authors examined the relationship between thiazide-type diuretics and fluid spaces in a cohort of hypertensive patients in a retrospective study of 60 stable hypertensive patients without renal abnormalities who underwent whole-body bioimpedance analysis. Overhydration was greater in the diuretic group, but only to a nonsignificant degree (5.9 vs. 2.9%; P=.21). The total body water did not differ in the two groups (41.8 L vs. 40.5 L; P=.64). Extracellular fluid volume (ECV) (19.7 L vs. 18.5 L; P=.35) and intracellular fluid volume (ICV) spaces (20.8 L vs. 21.3 L; P=.75) were also not significantly different in the two groups. The ratio of ICV:ECV, however, appeared different: 1.05 vs 1.15 (P=.017) and the effect was maintained in the linear regression-adjusted model (β coefficient: -0.143; P=.001). The diuretic-related distortion of ICV:ECV ratio indicates potential fluid redistribution in hypertensive patients, with ICV participating in the process.

The presence of peritoneal dialysate when performing bioimpedance analysis may affect body composition measurements. The aim of this study was to evaluate the impact of dialysate on body composition measurements in Asians. Forty-one patients undergoing maintenance peritoneal dialysis in our hospital peritoneal dialysis unit were included in this study. Dialysate was drained from the abdomen prior to measurement, and bioimpedance analysis was performed using multi-frequency bioimpedance analysis, with each subject in a standing position (D-). Dialysate was then administered and the measurement was repeated (D+). The presence of peritoneal dialysate led to an increase in intracellular water (ICW), extracellular water (ECW), and total body water (D-: 20.33 ± 3.72 L for ICW and 13.53 ± 2.54 L for ECW; D+: 20.96 ± 3.78 L for ICW and 14.10 ± 2.59 L for ECW; P

Fluid retention is a recognized feature of acute mountain sickness. However, accurate assessment of hydration, including the quantification of body water, has traditionally relied on expensive and non-portable equipment limiting its utility in the field setting. We compared the assessment of total body water (TBW) and their relationship to total body weight using two non-invasive methods using the NICas single-frequency bioimpedance analysis (SF-BIA) system and the BodyStat QuadScan 4000 multifrequency BIA system (MF-BIA). TBW measurements were performed at rest at sea level and at high altitude (HA) at 3833 m postexercise and at rest and thereafter at rest at 4450 m and 5129 m on 47 subjects. The average age was 34.5 ± 9.3 years with an age range of 21-54 years (70.2% male). There were strong correlations between TBW assessment with both methods at sea level (r = 0.90; 95% CI 0.78-0.95: P

Reliable and valid body composition assessment is important in both clinical and research settings. A multitude of methods and techniques for body composition measurement exist, all with inherent problems, whether in measurement methodology or in the assumptions upon which they are based. This review is focused on currently applied methods for in vivo measurement of body composition, including densitometry, bioimpedance analysis, dual-energy X-ray absorptiometry, computed tomography (CT), magnetic resonance techniques and anthropometry. Multicompartment models including quantification of trace elements by in vivo neutron activation analysis, which are regarded as gold standard methods, are also summarized. The choice of a specific method or combination of methods for a particular study depends on various considerations including accuracy, precision, subject acceptability, convenience, cost and radiation exposure. The relative advantages and disadvantages of each method are discussed with these considerations in mind.

Aim Several operative definitions and screening methods for sarcopenia have been proposed in previous studies; however, the opinions of researchers still differ. We compared the prevalence of sarcopenia using two different algorithms: (i) the European working group on sarcopenia in older people (EWGSOP)-suggested algorithm using gait speed as the first step; and (ii) the muscle mass and strength algorithm. Methods A population-based, cross-sectional survey of adults aged over 65 years was carried out. Data on a total of 4811 participants were available for analysis. Gait speed, grip strength and appendicular skeletal muscle mass were assessed to determine sarcopenia. Appendicular skeletal muscle mass was estimated from bioimpedance analysis measurements and expressed as skeletal muscle mass index. Grip strength and skeletal muscle mass index were considered to be low if they fell below the threshold of the lowest 20% of values measured in a subset of healthy subjects. We compared the prevalence rates of sarcopenia determined by the two algorithms. Results The prevalence rate of sarcopenia in a representative sample of older Japanese adults was 8.2% for men and 6.8% for women based on the EWGSOP algorithm. The two algorithms identified the same participants as sarcopenic, the only difference being the EWGSOP algorithm classified an additional seven participants (0.15%) into sarcopenia compared with the muscle mass and strength algorithm. Conclusion It is debatable whether inclusion of gait speed is necessary when screening for sarcopenia in community-dwelling older adults. Future research should examine the necessity of including gait speed in algorithms and the validity of cut-off values. Geriatr Gerontol Int 2014; 14 (Suppl. 1): 46–51.

Bioimpedance analysis (BIA) is reported to be useful in assessing dry weight (DW) in patients on hemodialysis (HD), but its exact role has never been clearly defined. We reviewed our experience of using the BIA measure of reactance (Xc) in pediatric patients on chronic HD. Our approach is currently based on identifying a range of patient-specific Xc values at which a child can be considered at DW according to a multidisciplinary assessment. Values lower than the patient-specific limit suggests the need for a reduction in DW, whereas values higher than the limit suggest that DW should be increased. The accuracy of our approach was retrospectively assessed by analyzing the left ventricular mass index (LVMI) and the incidence of pulmonary edema (PE) in two groups: The first consisted of 13 patients (median age 15.6 years) on dialysis in 2007, before the introduction of the BIA-based approach; the second included 18 patients (median 14.8 years) on dialysis in 2011. In 2007, three children experienced four episodes of PE, whereas no PE occurred in 2011. The median LVMI was 56.8 g/m(2.7) in 2007, and 44.5 g/m(2.7) in 2011 (P 38.5 g/m(2.7)) was 92.3% in 2007 and 61.1% in 2011 (P < 0.05). There were no between-group differences in terms of blood pressure, antihypertensive medications, percentage of symptomatic sessions, or biochemistry. In conclusion, a simple approach based on BIA may be useful in assessing DW in pediatric patients on HD, and thus improve their cardiovascular status.

The aim of the present study was to elucidate whether self-assessed masticatory ability (masticatory ability) is significantly related to muscle strength of the body evaluated as handgrip strength and skeletal muscle mass of the whole body (kg) (SMM) after adjusting for confounding variables, including, age, gender, height, weight, employment status, type of household, educational background, social interaction, chronic medical conditions, smoking habit, drinking habits and dentition status among the elderly. A total of 381 persons aged 67-74 years were enrolled. Masticatory ability was classified into one of three categories: ability to chew all kinds of food, ability to chew only slightly hard food or ability to chew only soft or pureed food. Handgrip strength was measured, and bioimpedance analysis was used to estimate SMM. One-way analysis of variance and Bonferroni methods were used to examine differences in handgrip strength and SMM among the three groups of masticatory ability. An ordinal regression model was conducted with masticatory ability as the dependent variable and handgrip strength as the principal independent variable. Handgrip strength was significantly lower in those individuals who could chew only soft or pureed food than in those individuals who could chew all kinds of food. No significant difference in SMM was found among the three groups of masticatory ability. Masticatory ability was significantly related to handgrip strength after adjusting for SMM, dentition status and background factors. Chewing ability may be related to muscle strength of the body evaluated as handgrip strength, but not evaluated as SMM.

The body cell mass (BCM) is an important measure of macronutrient status, but measurements are difficult to obtain outside of sophisticated research laboratories. Bioimpedance analysis (BIA) is a simple technique that holds promise as a means of estimating body composition. The purpose of this study was to evaluate the ability of BIA to estimate changes in BCM as measured by whole body counting of 40K (TBK).Paired studies of BCM, including both TBK and BIA, were compared in 87 human immunodeficiency virus-positive subjects and in 62 healthy, weight-stable control adults. Potential errors in the predictions were examined.BCM change by TBK and BIA correlated closely (r = .755). After accounting for errors related to repeat measures of TBK, the correlation coefficient was .784, with a standard error of the estimate of 1.24 kg. The differences between predicted and measured BCM change were consistent with a normal distribution. However, there was a systematic error in prediction, with BIA underpredicting the magnitudes of both gains and losses in BCM by TBK.BIA is a useful surrogate for measuring changes in BCM in clinical circumstances. Because TBK assesses only intracellular potassium, whereas BIA reflects all intracellular cations, the underprediction of BCM change by BIA compared with TBK could be related to changes in intracellular potassium concentration as a result of malnutrition or its treatment.

Objective To describe the measurement challenges faced and to evaluate the measurement quality obtained with massively obese individuals. Method: A cross-sectional analysis of 107 individuals with body mass indices (kg/m2) ≥50 was conducted. Individuals had their body fat measured via bioimpedance analysis (BIA), their serum leptin levels measured via radioimmunoassay (RIA), and height and weight measured via both laboratory scales and self-report. Results: Serum leptin appeared to be measured accurately, provided the serum was diluted prior to conducting the RIA. Difficulties remained, however, in evaluating what was an unusual or expected value of leptin among individuals this large. Measures of impedance appeared to provide reasonable ordinal indications of body fatness. However, currently available equations for converting measures of impedance to estimates of percent body fat were highly inaccurate. Self-reported height and weight were reasonably good proxies of measured height and weight among individuals who reported their height and weight. However, a substantial proportion were unable to provide estimates. Discussion: The above results suggest there are substantial challenges when trying to obtain meaningful measurements regarding obesity-related variables among massively obese individuals. Other logistic challenges also are discussed. It is hoped future research is directed at overcoming some of these challenges. © 1998 by John Wiley & Sons, Inc. Int J Eat Disord 24: 275–284, 1998.

The 1993 ASPEN Research Workshop examined research and clinical advances in the study of human body composition. The workshop had two themes: (1) compartments of the body and their measurement, and (2) clinical applications of body composition measurements. There were 12 speakers of varied backgrounds who gave short lectures followed by panel discussions. Speakers explored the validity and potential uses of new body composition methodologies, including dual-energy x-ray absorptiometry, multiple frequency bioimpedance analysis, computerized axial tomography, magnetic resonance imaging, nuclear magnetic resonance spectroscopy, neutron inelastic scattering, and gamma-ray resonance. The application of these methods to chronically and acutely ill hospitalized patients was described. The study of body composition is an emerging distinct research area within the broad study of human biology. This conference provided an overview of important new advances in the study of human body composition.