Body composition analysis with bioelectric impedance in adult Indians with ESRD: Comparison with healthy population

[Bioelectrical impedance vectors in the Colombian university population]

INTRODUCTION

body composition (BC) analysis is an essential element in clinical nutritional practice. Bioelectrical impedance is one of the most widely used techniques for estimating BC. Several approaches have been proposed to reduce the margin of error it presents, ensuring its application in all populations. One of them is the use of impedance vectors, using tolerance ellipses.

OBJECTIVE

to compare the sample vectors with the Italian population and to determine specific tolerance ellipses for the Colombian university population.

MATERIALS AND METHODS

observational cross-sectional study in 608 university students. Participation was at convenience and voluntary, between February 2022 and March 2023. BIVA 2002 software was used to calculate the tolerance ellipses and BIVA confidence to compare the vectors of the ellipses with the Italian population using Hotelling's T2 test, which was considered as significant at p < 0.05.

RESULTS

R/H and Xc/H measurements were higher in females (420.75 ± 56.012 Ω/m vs 308.7508 ± 41.81 Ω/m) and (46.15 ± 5.79 Ω/m vs 39.44 ± 5.01 Ω/m), respectively. The impedance vectors were positioned over the upper quadrants of the RXc plot, evidencing significant differences in the distribution of the composition vectors between samples.

CONCLUSIONS

the vectors of the Colombian university students were different from the reference population, so it was necessary to determine the specific ellipses.

Changes in body composition in relation to estimated glomerular filtration rate and physical activity in predialysis chronic kidney disease

Background

Early body composition changes, associated with physical inactivity and disease advancement are devastating for patient-related outcomes in predialysis chronic kidney disease (CKD), thus warranting a detailed analysis of body composition beyond conventional measures.

Methods

The study included 40 subjects diagnosed with CKD; recruited between January to May 2021. Body composition was measured using the multifrequency analyzer, InBody 770. International Physical Activity Questionnaire-Short Form was used to assess physical activity. Suitable statistical analyses were performed using SPSS 21.0.

Results

The mean age of the subjects was 58.68 ± 12.24 years. Sarcopenic obesity was prevalent in 62.5% of the subjects. Body mass index under identified obesity by 15% compared to percent body fat, especially in subjects with low muscle mass. The decline in a unit of estimated glomerular filtration rate (eGFR) significantly correlated with a decrease in weight (p = 0.02), body fat mass (p = 0.05), visceral fat area (p = 0.05), and phase angle (p = 0.01) with marginal changes in waist-hip ratio and extracellular water/total body water. The effect of physical activity on skeletal muscle mass was homogeneous between low and moderate levels, but significantly different from high activity level.

Conclusion

Changes in fat and fluid compartment were associated with eGFR decline, whereas higher physical activity positively affected body composition.

Assessment of total and regional bone mineral density using bioelectrical impedance vector analysis in elderly population

This study aimed to investigate the relationship between bone mineral density (BMD) and height-adjusted resistance (R/H), reactance (Xc/H) and phase angle (PhA). A total of 61 male and 64 female subjects aged over 60 years were recruited from middle Taiwan. The R and Xc were measured using Bodystat Quadscan 4000 at a frequency of 50 kHz. BMD at the whole body, L2–L4 spine, and dual femur neck (DFN), denoted as BMD_Total, BMD_L2–L4, and BMD_DFN, were calculated using a Hologic DXA scanner. The R-Xc graph was used to assess vector shift among different levels of BMD. BMD was positively correlated with Xc/H and negatively correlated with R/H (p < 0.001). The General Linear Model (GLM) regression results were as follows: BMD_Total = 1.473–0.002 R/H + 0.007 Xc/H, r = 0.684; BMD_L2–L4 = 1.526–0.002 R/H + 0.012 Xc/H, r = 0.655; BMD_DFN = 1.304–0.002 R/H + Xc/H, r = 0.680; p < 0.0001. Distribution of vector in the R-Xc graph was significantly different for different levels of BMD_Total, BMD_L2–L4 and BMD_DFN. R/H and Xc/H were correlated with BMD in the elderly. The linear combination of R/H and Xc/H can effectively predict the BMD of the whole body, spine and proximal femur, indicating that BIVA may be used in clinical and home-use monitoring tool for screening BMD in the elderly in the future.

Differences in Amino Acid Loss Between High-Efficiency Hemodialysis and Postdilution and Predilution Hemodiafiltration Using High Convection Volume Exchange-A New Metabolic Scenario? A Pilot Study

OBJECTIVE

The objective of the study was to quantify the loss of total amino acids (TAAs), nonessential amino acids, essential amino acids, and branched chain amino acids (BCAAs) produced by high-efficiency hemodialysis (HEHD), postdilution hemodiafiltration (HDFpost), and predilution hemodiafiltration (HDFpre) using high ultrafiltration volumes; and to define the specific AA losses registered in HEHD, HDFpost, and HDFpre; to identify a potential metabolic and nutritional decline into protein energy wasting; to compare AA analysis of arterial blood samples taken from healthy controls and patients with end-stage renal disease undergoing hemodialysis.

DESIGN AND METHODS

Identical dialysis monitors, membranes, and dialysate/infusate were used to homogenize extracorporeal body influence. Ten patients were recruited and randomized to receive treatment with HEHD, HDFpost, and HDFpre it was used on-line dialytic water methodologies (OL); patients' AA arterial concentrations were measured at the start and on completion of dialysis; TAA from the dialyzer filter was calculated, and baseline levels were subsequently compared with findings obtained 1 year later. Finally, the results obtained were compared with the data from a study of 8 healthy volunteers conducted using bioimpedance analysis and laboratory blood tests to assess nutritional status.

RESULTS

A higher convective dose results in a higher weekly loss of TAA, nonessential AAs, essential AAs, and BCAAs (HEHD: 15.7 g; HDFpost-OL: 16.1 g; HDFpre-OL: 16.3 g, P < .01). After 12 months, the same hemodialys patients showed a reduced body and water intracellular mass and reduced phase angle. Arterial concentrations of TAAs and BCAAs were lower than those detected in healthy subjects (P < .01).

CONCLUSION

The study shows that the AA losses in dialytic liquid are greater after high exchange volume HDF techniques, especially HDFpre. The AA losses are not metabolically compensated, so these increase the derangements of predialytic arterial plasma AA levels. Both AA losses and arterial AA perturbations further worsened body composition already after 12 months of additional dialysis.

Evaluation of Body Composition in Hemodialysis Thai Patients: Comparison between Two Models of Bioelectrical Impedance Analyzer and Dual-Energy X-Ray Absorptiometry

Background

Body composition measurement is very important for early nutritional care in hemodialysis patients. Dual-energy X-ray absorptiometry (DXA) is a gold standard test, but clinically limited. Bioelectrical impedance analysis (BIA) with multifrequency technique is a practical and reliable tool.

Objective

This cross-sectional study was aimed to compare the agreement of BIA with DXA in measurement of body composition in hemodialysis patients and to evaluate their associated factors.

Methods

Body composition was measured by 2 BIA methods (InBody S10 and InBody 720) and DXA after a hemodialysis session. A total of 69 measurements were included. Pearson's correlation and Bland and Altman analysis were used to determine the correlation of body composition between methods and to compare the methods agreement, respectively.

Results

The correlation coefficients of body compositions were strong between DXA and InBody S10 (fat mass index (FMI): r=0.95, fat-free mass index (FFMI): r=0.78) and also between DXA and InBody 720 (FMI: r=0.96, FFMI: r=0.81). Comparing to DXA, the means of each body composition measured by InBody S10 method were not significantly different in each gender, but differences were found in FM, %FM, and FMI measured by InBody 720.

Conclusions

In maintenance hemodialysis patients, the measurement of body composition with DXA and both BIA methods had highly significant correlations; practically, BIA method could be used as an instrument to follow FM and FFM and to measure the edematous stage. Further studies with large populations are warranted.

Diagnostic Accuracy of Bioelectrical Impedance Analysis Parameters for the Evaluation of Malnutrition in Patients Receiving Hemodialysis

BACKGROUND

In the absence of a gold standard technique for assessing nutrition status in patients receiving hemodialysis (HD), we aimed to determine the diagnostic accuracy of single-frequency (50 kHz) bioelectrical impedance analysis parameters, resistance/height (R/H), reactance/height (Xc/H), and impedance/height (Z/H), and their cutoff points for malnutrition.

METHODS

The reference standards, Subjective Global Assessment (SGA), Malnutrition Inflammation Score, and Nutritional Risk Screening 2002, were performed at baseline and then once a year for 2 years. At least 2 assessments for each reference standard were performed during the monitoring period, and those patients who were assessed as malnourished on at least 2 consecutive occasions were classified as malnourished.

RESULTS

A total 101 patients receiving HD were evaluated. R/H and Z/H demonstrated low to moderate accuracy to diagnose malnutrition in men and low accuracy in women, whereas the accuracy of Xc/H was uncertain. The cutoff points of bioelectrical impedance vector analysis (BIVA) parameters, determined based on the SGA to maximize sensitivity and specificity simultaneously, were: R/H ≥330.05 and ≥420.92 ohms/m for men and women, respectively; Z/H ≥332.71 and ≥423.19 ohms/m for men and women, respectively. In men, sensitivity based on the cutoff points of R/H and Z/H together ranged from 73% to 89% and specificity ranged from 49% to 50%. In women, sensitivity ranged from 58% to 80% and specificity from 48% to 55%.

CONCLUSION

BIVA parameters demonstrated low to moderate accuracy in men and low accuracy in women for the diagnosis of malnutrition.

Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients

OBJECTIVE

The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW.

DESIGN

Prospective (18 months).

SETTING

University Hospital of Heraklion, Crete, Greece.

SUBJECTS

Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD.

MAIN OUTCOME MEASURES

At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW).

RESULTS

Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification.

CONCLUSIONS

Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis.

Anthropometric Predictors of Bio-Impedance Analysis (BIA) Phase Angle in Healthy Adults

INTRODUCTION

Phase Angle (PhA) is a ratio of whole body reactance and resistance obtained from Bioelectrical Impedance Analysis (BIA). It indicates cellular health and integrity and is considered as prognostic tool in medical disorders. In spite of prognostic potentials of PhA, it has limited usefulness in clinical practice and in population studies because of non-availability of normal population reference limits for comparison. Moreover, it is influenced by various factors like age, sex, race and body composition (i.e. body fat, muscle mass, visceral fat, body cell mass, total body water, etc).

AIM

The aim of this study was to evaluate predictors of phase angle which will be useful in formulation of reference values for Indian population.

MATERIALS AND METHODS

BIA was performed by Tanita Body Composition Analyser on healthy adults aged 17-24 years. The inbuilt software measured the phase angle by the formula: Phase angle (PhA) = Reactance (xc)/Resistance (R)* (180/π). Phase angle values were compared across categories of age, sex, weight, height, Body Mass Index (BMI), total fat, visceral fat and muscle mass.

RESULTS

Mean value of phase angle was found to be 5.65. Phase angle was significantly (p< 0.001) higher in male than in female. Phase angle was significantly predicted from height (p< 0.001), weight (p< 0.002), muscle mass (p< 0.002) and visceral fat (p< 0.02) in multiple regression models.

CONCLUSION

Phase angle differs across anthropometric and body composition categories. Thus height, weight and muscle mass should also be taken into consideration while deriving population specific reference limits of phase angle.

Bioelectrical impedance vector analysis in critically ill patients: a prospective, clinician-blinded investigation

Introduction

Assessment of fluid status in critically ill patients is challenging. We aimed to assess the feasibility and validity of bioelectrical impedance vector analysis (BIVA) as a measure of hydration in critically ill patients.

Methods

We performed twice-daily BIVA measurements and fluid balance calculations and recorded physiological variables in mechanically ventilated patients within 24 h of intensive care unit (ICU) admission for up to 5 days. Treating clinicians were blinded to BIVA results.

Results

We performed 344 BIVA measurements in 61 patients. According to BIVA, 14 patients (23 %) were dehydrated, 22 (36 %) were normally hydrated and 25 (41 %) were overhydrated upon ICU admission. Patients with normal BIVA hydration were less sick, had fewer comorbidities and had less deranged physiology than patients found to be dehydrated or overhydrated with BIVA. Cumulative fluid balance increased in patients found to be dehydrated with BIVA by a mean of 3.4±2.2 L, whereas in patients found to be overhydrated with BIVA, it decreased by a mean of 4.5±6.9 L. In patients found to be normally hydrated with BIVA, fluid balance remained unchanged. BIVA-defined hydration increased with 1 L (median change 1.5 %, P =0.09) or 2 L (median change 0.7 %, P =0.09) of calculated fluid gains. BIVA-defined hydration decreased (median change −0.8 %, P =0.02) with a negative cumulative fluid balance of >2 L. BIVA-defined hydration between first and last measurement correlated with the corresponding change in fluid balance (ρ =0.25, P =0.05).

Conclusions

BIVA is feasible in critically ill patients. Its validity is supported by the observed characteristics of patients with different degrees of BIVA hydration upon admission and by different fluid management of such patients by blinded clinicians. The sensitivity of repeated BIVA hydration measurements to detect fluid accumulation or fluid balance changes <2 L was low, however. These contradictory findings provide the rational basis for studies of BIVA-assisted fluid management in ICU patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1009-3) contains supplementary material, which is available to authorized users.

A longitudinal study of nutritional and inflammatory status in patients on dialysis

OBJECTIVE

Several anthropometric, laboratory and bioelectrical impedance parameters of nutritional status and inflammation are often used as prognostic indices in patients on dialysis. Their longitudinal assessment is necessary for the estimation of their true prognostic value. We aim to estimate this prognostic value in better-nourished dialysis patients, which are commonly under-represented in pertinent studies.

METHODS

The design is a prospective case series. Pertinent parameters were studied three times during a 20-month period in 47 haemodialysis (HD) and 27 peritoneal dialysis (PD) patients with a low malnutrition-inflammation score (MIS). Mortality rate was assessed three years after the initial evaluation. Correlation coefficients were calculated between mortality rate, the studied parameters and their alteration.

RESULTS

Serum albumin of less than 40 g/l was strongly correlated with mortality risk. The alteration of studied parameters during a short period of time does not allow for long-term prediction of mortality risk.

CONCLUSION

Serum albumin had the strongest predictive value of all the pertinent parameters in the study. Thus, better conjugate clinical and laboratory measurements should be developed for patients on PD, as well as for those with a relatively low MIS.

Bioelectrical phase angle and impedance vector analysis--clinical relevance and applicability of impedance parameters

BACKGROUND & AIMS

The use of phase angle (PhA) and raw parameters of bioelectrical impedance analysis (BIA) has gained attention as alternative to conventional error-prone calculation of body composition in disease. This review investigates the clinical relevance and applicability of PhA and Bioelectrical Impedance Vector Analysis (BIVA) which uses the plot of resistance and reactance normalized per height.

METHODS

A comprehensive literature search was conducted using Medline identifying studies relevant to this review until March 2011. We included studies on the use of PhA or BIVA derived from tetrapolar BIA in out- and in-patient settings or institutionalized elderly.

RESULTS

Numerous studies have proven the prognostic impact of PhA regarding mortality or postoperative complications in different clinical settings. BIVA has been shown to provide information about hydration and body cell mass and therefore allows assessment of patients in whom calculation of body composition fails due to altered hydration. Reference values exist for PhA and BIVA facilitating interpretation of data.

CONCLUSION

PhA, a superior prognostic marker, should be considered as a screening tool for the identification of risk patients with impaired nutritional and functional status, BIVA is recommended for further nutritional assessment and monitoring, in particular when calculation of body composition is not feasible.

Comparison of nutritional parameters among adult and elderly hemodialysis patients

AIM

The aim of this study was to compare the nutritional biochemical parameters, prealbumin levels, and bioimpedance analysis parameters of adult and elderly hemodialysis (HD) patients.

METHODS

This prospective cross-sectional study included 50 adult HD patients (42.0 % female). Nutritional status was assessed by post-dialysis multifrequency bioimpedance analysis (BIA), serum prealbumin and other nutritional biochemical parameters.

RESULTS

Mean age of patients was 57.4±15.1 years (range: 30-83 years) and mean dialysis duration was 68.3 ± 54.5 months (range: 3-240 months). When the patients were divided into two groups according to age of patients (<65 and ≥65), prealbumin (p=0.003), blood urea nitrogen (BUN) (p=0.000), serum creatinine (p=0.013), albumin (p=0.016), protein catabolic rate per normalized body weight (nPCR) (p=0.001), intracellular water (ICW)/total body weight (0.003) , body fat mass (p00.000), lean body mass (p=0.031), lean dry mass (p=0.001), illness marker (p=0.005), basal metabolism (p=0.007), body mass index (BMI) (p=0.028), body fat mass index (BFMI) (p=0.000), fat free mass index (FFMI) (p=0.040) values were significantly different between the groups. In the elderly patients (age ≥65), body fat mass, illness marker, BMI, BFMI were higher compared to adult patients (age <65). Additionally, in the elderly patients, prealbumin, BUN, creatinine, albumin, nPCR, ICW/ total body weight, lean body weight, lean dry weight, basal metabolism and FFMI were lower than adult patients.

CONCLUSIONS

Our results indicate that BFMI were higher, albumin, prealbumin, nPCR and lean body mass and FFMI were lower in elderly patients compared to adults. These results imply that elderly HD patients may be prone sarcopenic obesity and may require special nutritional support.

Wet or dry in dialysis--can new technologies help?

Whereas clinical assessment remains the mainstay of estimating dry weight in dialysis patients, subtle over- and under-hydration may remain undetected, which may result in increased short- and long-term morbidity. Various technological tools have been developed to aid the clinician in the assessment of fluid state in dialysis patients. Chest X-ray is useful in clinical management, but does not fulfill the need for rapid, noninvasive bedside testing. Vena cava echography provides a reliable estimation of right atrial pressure and was shown to be useful in the clinical management of dialysis patients, but the timing of measurement is of critical importance. New developments in bioimpedance techniques hold great promise for the routine application of this technique in the assessment and follow-up of hydration state. Cardiac biomarkers have a strong prognostic value, and may reflect overhydration indirectly because of its effect on left ventricular stress. Blood volume monitoring as a tool to assess dry weight needs further validation and standardization. Summarizing technological tools may certainly aid the clinician in the assessment of fluid state, but should always be interpreted in the clinical context of the patient. Controlled studies are needed to definitively establish the role of technological tools in detecting dry weight.