Bioelectrical Impedance Analysis-Derived Phase Angle Predicts Protein-Energy Wasting in Maintenance Hemodialysis Patients

Association between phase angle and diabetic peripheral neuropathy in Type 2 diabetes patients

BACKGROUND

Diabetic peripheral neuropathy (DPN), the very prevalent microvascular complication of type 2 diabetes mellitus (T2DM), severely threatens the quality of life of diabetic patients. Thus, prevention of DPN is extremely important for public health, and the identification of potential biomarkers may help with early prevention. Our work determined the association between phase angles (PhAs) and the risk of DPN in T2DM patients.

MATERIALS AND METHODS

This cross-sectional study recruited 697 T2DM patients from the Third Affiliated Hospital of Soochow University. All patients were divided into the non-diabetic peripheral neuropathy group and diabetic peripheral neuropathy group, and the DPN group was further divided into low, medium, and high diabetic foot ulcer risk groups according to vibration perception threshold results. Using univariate and multivariate logistic regression analyses continuously, the relationship between PhAs (arms, legs, trunk, and whole body) and the risk of DPN were evaluated. Further analysis was conducted on different subgroups of the study population.

RESULTS

After adjusting for the potential covariates, multivariate logistic regression analyses indicated that PhAs of the arms, legs, and whole body correlated inversely with the risk of DPN. However, the PhA of the trunk had no significant correlation with DPN. According to the stratified subgroup analysis, the negative association between PhA of the whole body and the risk of DPN remained significant in the sex and BMI group except for participants with BMI ≥ 28 kg/m².

CONCLUSIONS

For the first time, PhAs were acknowledged to be independently associated with DPN. Further exploration is needed to explain the findings.

Associations between bioelectrical impedance analysis-derived phase angle, protein-energy wasting and all-cause mortality in older patients undergoing haemodialysis

AIM

Protein-energy wasting (PEW) is a common syndrome in patients undergoing haemodialysis (HD) and is associated with poor prognosis. Bioelectrical impedance analysis (BIA)-derived phase angle (PA) is useful for predicting PEW, but sex and age need to be considered. We aimed to reveal sex-specific cut-off values of PA predicting PEW in HD patients aged ≥65.

METHODS

This two-centre retrospective cohort study included patients on HD who underwent BIA. PEW was detected using the International Society of Renal Nutrition and Metabolism (ISRNM) criteria as a reference. The PA was measured using a multifrequency bioimpedance device. Sex-specific cut-off values of PA predicting PEW were detected by receiver-operator characteristic analysis. We investigated the association between PEW determined using sex-specific cut-off values for PA and all-cause mortality.

RESULTS

This study included 274 patients undergoing HD, with a median age of 75 (70-80) years, mean PA of 3.8 ± 1.1° and PEW of 43%. Over a median follow-up duration of 1095 (400-1095) days, 111 patients died. Cut-off values of PA predicting PEW were as follows: female, 3.00° (sensitivity, 87.3%; specificity, 77.5%), and male, 3.84° (sensitivity, 77.6%; specificity, 71.4%). The kappa coefficient between sex-specific cut-off values of the PA and ISRNM criteria had a moderate coincidence level of 0.55. PEW detected by PA was independently associated with all-cause mortality (hazard ratio: 2.40; 95% confidence interval: 1.51-3.85; p < .001).

CONCLUSIONS

Sex-specific cut-off values for PA in older HD patients may be useful as a screening tool for predicting PEW and mortality.

Integrating classification and regression learners with bioimpedance methods for estimating weight status in infants and juveniles from the southern Cuba region

OBJECTIVE

The search for other indicators to assess the weight and nutritional status of individuals is important as it may provide more accurate information and assist in personalized medicine. This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy younger volunteers from Southern Cuba Region.

METHODS

A pilot random study at the Pediatrics Hospital was conducted. The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 776 female and male volunteers are studied. Along the age and sex in the cohort, volunteers with class I obesity, overweight, underweight and with normal weight are considered. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. The bioimpedance analyser is used, collecting fundamental bioelectrical and other parameters of interest. A classification model are performed, followed by a prediction of the body mass index.

RESULTS

The results derived from the classification leaner reveal that the size, body density, phase angle, body mass index, fat-free mass, total body water volume according to Kotler, body surface area, extracellular water according to Kotler and sex largely govern the weight status of this population. In particular, the regression model shows that other bioparameters derived from impedance measurements can be associated with weight status estimation with high accuracy.

CONCLUSION

The classification and regression predictive models developed in this work are of the great importance to assist the diagnosis of weigh status with high accuracy. These models can be used for prompt weight status evaluation of younger individuals at the Pediatrics Hospital in Santiago de Cuba, Cuba.

Phase angle as a prognostic indicator in critically ill children: A systematic review

Phase angle (PhA) may reflect the integrity of cellular membranes, hydration status, and total body cell mass. Studies have shown that PhA can be used as a good predictor for evaluation of disease severity in critically ill adults. However, there is a lack of studies assessing the association between PhA and clinical outcomes in critically ill children. This systematic review described the association between PhA at pediatric intensive care unit (PICU) admission with clinical outcomes in critically ill children. The search was conducted using PubMed/Medline, Scopus, Web of Science, EMBASE and LILACS until July 22, 2022. Studies that evaluate the association between PhA at PICU admission in critically ill children and clinical outcomes were eligible. Data regarding population, study design, setting, bioelectrical impedance analysis (BIA) protocol used, PhA classification, and outcome analysis were extracted. Risk of bias was assessed by Newcastle-Ottawa Scale. Among the 4669 articles screened, five prospective studies were included. The studies have shown association between lower values of PhA at PICU admission with longer PICU and hospital length of stay, duration of mechanical ventilation, septic shock, and higher mortality risk. Small sample size, different clinical conditions, and methodological differences of the studies regarding BIA equipment and cutoffs of PhA were observed. Although the studies have limitations, the PhA has a potential role in predicting clinical outcomes in critically ill children. Larger studies with standardized PhA protocols and other relevant clinical outcomes are necessary.

Skeletal muscle atrophy in clinical and preclinical models of chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) are often regarded as experiencing wasting of muscle mass and declining muscle strength and function, collectively termed sarcopenia. The extent of skeletal muscle wasting in clinical and preclinical CKD populations is unclear. We evaluated skeletal muscle atrophy in preclinical and clinical models of CKD, with multiple sub-analyses for muscle mass assessment methods, CKD severity, sex and across the different preclinical models of CKD. We performed a systematic literature review of clinical and preclinical studies that measured muscle mass/size using the following databases: Ovid Medline, Embase and Scopus. A random effects meta-analysis was utilized to determine standard mean difference (SMD; Hedges' g) between healthy and CKD. Heterogeneity was evaluated using the I2 statistic. Preclinical study quality was assessed via the Systematic Review Centre for Laboratory Animal Experimentation and clinical studies quality was assessed via the Newcastle-Ottawa Scale. This study was registered in PROSPERO (CRD42020180737) prior to initiation of the search. A total of 111 studies were included in this analysis using the following subgroups: 106 studies in the primary CKD analysis, 18 studies that accounted for diabetes and 7 kidney transplant studies. Significant atrophy was demonstrated in 78% of the preclinical studies and 49% of the clinical studies. The random effects model demonstrated a medium overall SMD (SMD = 0.58, 95% CI = 0.52-0.64) when combining clinical and preclinical studies, a medium SMD for the clinical population (SMD = 0.48, 95% CI = 0.42-0.55; all stages) and a large SMD for preclinical CKD (SMD = 0.95, 95% CI = 0.76-1.14). Further sub-analyses were performed based upon assessment methods, disease status and animal model. Muscle atrophy was reported in 49% of the clinical studies, paired with small mean differences. Preclinical studies reported significant atrophy in 78% of studies, with large mean differences. Across multiple clinical sub-analyses such as severity of CKD, dialysis modality and diabetes, a medium mean difference was found. Sub-analyses in both clinical and preclinical studies found a large mean difference for males and medium for females suggesting sex-specific implications. Muscle atrophy differences varied based upon assessment method for clinical and preclinical studies. Limitations in study design prevented conclusions to be made about the extent of muscle loss with disease progression, or the impact of dialysis. Future work would benefit from the use of standardized measurement methods and consistent clinical staging to improve our understanding of atrophy changes in CKD progression, and analysis of biological sex differences.

The ability of phase angle and body composition to predict risk of death in maintenance hemodialysis patients

OBJECTIVE

The objective of this study was to investigate the ability of phase angle and body composition to identify risk factors for mortality among patients receiving maintenance hemodialysis (MHD) treatment.

METHODS

In this retrospective study, we examined the causes of death in 43 MHD patients who were treated at our hemodialysis center between January 2016 and December 2021 and compared the patients to 71 patients who survived during the same period. Body composition was measured using direct segmental multi-frequency bioelectrical impedance to obtain phase angle, fat-free mass (FFM), extracellular water/total body water (ECW/TBW), and waist circumference (WC). Laboratory data were also collected. Phase angle cut-off value-associated variables were identified using ROC analysis. The ability of body composition variables to identify risk factors for death in MHD patients was evaluated.

RESULTS

We found that cardiovascular disease was the most common cause of death among MHD patients. ROC curve analysis revealed that the optimal cut-off value for phase angle as a predictor of death risk in MHD patients was 4.50°. Additionally, lower phase angle, increased age, longer dialysis vintage, lower KT/V, and hypoproteinemia were identified as significant risk factors for death in MHD patients.

CONCLUSION

In conclusion, our findings suggest that cardiovascular disease is the leading cause of death among MHD patients and that lower phase angle, increased age, longer dialysis duration, and hypoproteinemia can be used to predict the risk of mortality in this patient population. The underlying mechanism by which lower phase angle can be used to predict the prognosis of MHD patients warrants further investigation.

Nutritional Assessments by Bioimpedance Technique in Dialysis Patients

Bioelectrical impedance analysis (BIA) has been extensively applied in nutritional assessments on the general population, and it is recommended in establishing the diagnosis of malnutrition and sarcopenia. The bioimpedance technique has become a promising modality through which to measure the whole-body composition in dialysis patients, where the presence of subclinical volume overload and sarcopenic obesity may be overlooked by assessing body weight alone. In the past two decades, bioimpedance devices have evolved from applying a single frequency to a range of frequencies (bioimpedance spectroscopy, BIS), in which the latter is incorporated with a three-compartment model that allows for the simultaneous measurement of the volume of overhydration, adipose tissue mass (ATM), and lean tissue mass (LTM). However, clinicians should be aware of common potential limitations, such as the adoption of population-specific prediction equations in some BIA devices. Inherent prediction error does exist in the bioimpedance technique, but the extent to which this error becomes clinically significant remains to be determined. Importantly, reduction in LTM has been associated with increased risk of frailty, hospitalization, and mortality in dialysis patients, whereas the prognostic value of ATM remains debatable. Further studies are needed to determine whether modifications of bioimpedance-derived body composition parameters through nutrition intervention can result in clinical benefits.

Comparison of bioimpedance equations and dual-energy X-ray for assessment of fat free mass in a Chinese dialysis population

PURPOSE

Bioelectrical impedance analysis (BIA) is simple, noninvasive, inexpensive and frequently used for estimating fat free mass (FFM). The aims of this study were to evaluate the applicability of different BIA equations on FFM in Chinese subjects, and to compare the difference in hemodialysis and peritoneal dialysis patients with healthy controls respectively.

METHODS

Dialysis patients and healthy adults were enrolled in this study, and the subjects were matched by age, gender, and the minimum sample size in each group was calculated using PASS. FFM estimated by BIA was calculated using equations of Kyle, Sun SS and Segal, and TBW/0.73. Dual-energy X-ray absorptiometry (DXA) method was set as reference method. Pearson's correlation and Bland-Altman analysis were used to test the validity of the BIA equations.

RESULTS

50 hemodialysis (HD) patients, 52 peritoneal dialysis (PD) patients and 30 healthy adults aged 22-67 y were included in this study. Age, height, weight, BMI and gender did not differ significantly among HD, PD patients, and healthy controls (p > 0.05), but BIA parameters were quite different (p＜0.01). Bland-Altman analysis showed that in healthy volunteers, all equations showed good agreement with DXA measured. For dialysis patients, the FFM predictions of different equations showed differences between HD and PD patients, and the equations seemed more applicable for HD patients.

CONCLUSION

The equations developed by healthy subjects might be not appropriate for dialysis patients, especially peritoneal dialysis patients. It is recommended to develop a specific BIA equation from dialysis population.

Simply adding oral nutritional supplementation to haemodialysis patients may not be enough: a real-life prospective interventional study

Introduction

Protein-energy wasting (PEW) is a common and serious co-morbidity in haemodialysis (HD) patients. Its importance as a prognostic factor has been increasingly recognised during the past decades. Much effort has been invested in the improvement of nutritional status and amelioration of consequences through different therapeutic approaches, either intradialytic parenteral nutrition or more commonly oral nutritional supplementation. In the article, we present the results of a prospective study in HD patients after 12 months of therapeutic intervention with oral nutritional supplements (ONS).

Methods

A total of 92 HD adult patients were enrolled in the study after 3 months of wash-out period. Baseline nutritional status was assessed using composite scores, laboratory markers, bioelectrical impedance analysis, and hand-grip strength test. Patients recognised as undernourished or at high risk for undernutrition received renal-specific commercially available ONS on HD day in addition to their regular diet. After 12 months, the effect of ONS on surrogate markers of undernutrition, serum albumin level, phase angle, and hand-grip strength was analysed in 71 surviving patients.

Results

After 12 months, data for 71 patients, 39 (54.9%) men, 62.4 ± 12.9 years, and median haemodialysis vintage 53.3 (IQR 27.5-92.8) months, were available. Patients were divided into three groups: group A patients were with normal nutritional status at baseline not necessitating ONS; group B patients received ONS; and group C patients were entitled to receive but refused to take ONS. The baseline results showed statistically significant differences between the groups in serum albumin levels and phase angle but not hand-grip strength. Differences between the groups remained statistically significant at month 12; we did not find any statistically significant positive changes within the groups, indicating no positive effect of intervention with ONS.

Conclusion

In a prospectively designed interventional single-centre study, we did not find a statistically significant change in surrogate markers of PEW in our cohort of HD patients, receiving ONS for 12 months. Since PEW is an independent risk factor influencing the survival of HD patients, efforts should be directed towards a timely and comprehensive nutritional approach, including intensive, personalised dietary counselling, increase in protein and energy intake and advocating tight control of nutritional status during HD treatment, possibly providing psychological support and motivation.

Application of Bioelectrical Impedance Analysis in Nutritional Management of Patients with Chronic Kidney Disease

Body composition measurement plays an important role in the nutritional diagnosis and treatment of diseases. In the past 30 years, the detection of body composition based on bioelectrical impedance analysis (BIA) has been widely used and explored in a variety of diseases. With the development of technology, bioelectrical impedance analysis has gradually developed from single-frequency BIA (SF-BIA) to multi-frequency BIA (multi-frequency BIA, MF-BIA) and over a range of frequencies (bioimpedance spectroscopy, BIS). As the clinical significance of nutrition management in chronic kidney disease has gradually become prominent, body composition measurement by BIA has been favored by nephrologists and nutritionists. In the past 20 years, there have been many studies on the application of BIA in patients with CKD. This review describes and summarizes the latest research results of BIA in nutritional management of patients with CKD including pre-dialysis, hemodialysis, peritoneal dialysis and kidney transplantation, in order to provide reference for the application and research of BIA in nutritional management of chronic kidney disease in the future.

Bioelectrical impedance analysis-derived phase angle predicts sarcopenia in patients on maintenance hemodialysis

BACKGROUND

This study aimed to investigate the association between phase angle (PhA) and sarcopenia and evaluate its performance as a sarcopenia predictor in patients receveing maintenance hemodialysis (MHD).

METHODS

All enrolled patients underwent handgrip strength (HGS) and the 6-m walk test, and muscle mass was measured using bioelectrical impedance analysis. Sarcopenia was diagnosed according to the diagnostic criteria of the Asian Sarcopenia Working Group. Logistic regression analysis was used to evaluate the PhA as an independent predictor of sarcopenia after adjusting for confounding factors. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of PhA in sarcopenia.

RESULTS

Two hundred forty-one patients receiving hemodialysis were enrolled in this study, and the prevalence of sarcopenia was 28.2%. Patients with sarcopenia presented a lower PhA value (4.7° vs 5.5°; P < 0.001), lower muscle mass index (6.0 vs 7.2 [kg/m² ]; P < 0.001), lower HGS (19.7 vs 26.0 [kg]; P < 0.001), and lower walk speed (0.83 ± 0.27 vs 0.92 ± 0.23 [m/s]; P = 0.007) than patients without sarcopenia. The odds of patients receiving MHD presenting with sarcopenia increased as PhA decreased, even after adjustment (odds ratio = 0.39; 95% CI, 0.18-0.85; P = 0.019). ROC analysis revealed that the best cutoff value of PhA for sarcopenia was 4.95° in patients receiving MHD.

CONCLUSION

PhA may be a useful and simple predictor for predicting patients undergoing hemodialysis who are at risk of sarcopenia. To further facilitate the application of PhA in the diagnosis of sarcopenia, more research need to be conducted.

Skeletal Muscle Complications in Chronic Kidney Disease

PURPOSE OF REVIEW

To provide an overview of the recent literature investigating the pathophysiology of skeletal muscle changes, interventions for skeletal muscle, and effects of exercise in chronic kidney disease (CKD).

RECENT FINDINGS

There are multiple CKD-related changes that negatively impact muscle size and function. However, the variability in the assessment of muscle size, in particular, hinders the ability to truly understand the impact it may have in CKD. Exercise interventions to improve muscle size and function demonstrate inconsistent responses that warrant further investigation to optimize exercise prescription. Despite progress in the field, there are many gaps in the knowledge of the pathophysiology of sarcopenia of CKD. Identifying these gaps will help in the design of interventions that can be tested to target muscle loss and its consequences such as impaired mobility, falls, and poor quality of life in patients with CKD.

Endothelial Damage and Muscle Wasting in Cardiac Surgery Patients

This is a post-hoc analysis to assess the effect of anesthesia, surgical trauma, and extracorporeal circuit on endothelial integrity, microvascular permeability, and extracellular fluid balance, as well as on skeletal muscle catabolism, in patients undergoing elective cardiac surgery. We included 127 well-nourished patients undergoing “on-pump” elective cardiac surgery. One day prior to surgery (D0) and again on postoperative day 7 (POD7), body mass index, body composition assessment, hand-grip strength (HGS), and mid-upper arm muscle circumference (MAMC) were measured. Patients were assigned to early recovery (ER) and late recovery (LR) groups, depending on the duration of ICU stay (cut-off 48 hours). The magnitude of change (Δ) in all parameters studied was assessed in ER versus LR groups, regarding (i) epithelial tissue dysfunction (Δ-Extra-Cellular Water percentage (Δ-ECW%), Δ-Phase Angle (Δ-PhA)), (ii) skeletal muscle mass catabolism (Δ-Skeletal muscle mass reduction%, Δ-Hand Grip Strength (Δ-HGS) and Δ-Mid Upper-Arm Muscle Circumference (Δ-MAMC)). Baseline measurements were similar in both groups. A significant difference was observed in all Δ-parameters studied (Δ-ECW%, Δ-PhA and muscle catabolism, Δ-HGS, Δ-MAMC), the worse results being correlated to the LR group. The results raise the issue that patients with early recovery may silently have pathological conditions, continuing even on the day of discharge - further research should be planned.

Nutritional Predictors of Mortality after 10 Years of Follow-Up in Patients with Chronic Kidney Disease at a Multidisciplinary Unit of Advanced Chronic Kidney Disease

Nutritional monitoring in advanced chronic kidney disease (ACKD) units provides personalized care and improves clinical outcomes. This study aimed to identify mortality risk factors in chronic kidney disease (CKD) patients on nutritional follow-up in the multidisciplinary ACKD unit. A retrospective cross-sectional observational study was conducted in 307 CKD patients’ stage 3b, 4−5 followed-up for 10 years. Clinical and nutritional monitoring was performed by malnutrition-inflammation score (MIS), biochemical parameters (s-albumin, s-prealbumin, and serum C-reactive protein (s-CRP), body composition measured by bioelectrical impedance analysis (BIA), anthropometry, and handgrip strength measurements. The sample was classified into non-survivors, survivors, and censored groups. Of the 307 CKD patients, the prevalence of protein-energy wasting (PEW) was 27.0% using MIS > 5 points, s-CRP > 1 mg/dL was 19.20%, and 27.18% died. Survivors had higher significant body cell mass (BCM%) and phase angle (PA). Survival analyses significantly showed that age > 72 years, MIS > 5 points, s-prealbumin ≤ 30 mg/dL, PA ≤ 4°, and gender-adjusted handgrip strength (HGS) were associated with an increased risk of mortality. By univariate and multivariate Cox regression, time on follow-up (HR:0.97), s-prealbumin (HR:0.94), and right handgrip strength (HR:0.96) were independent predictors of mortality risk at 10 years of follow-up in the ACKD unit. Nutritional monitoring in patients with stage 3b, 4−5 CKD helps to identify and treat nutritional risk early and improve adverse mortality prognosis.

Impact of phase angle and sarcopenia estimated by bioimpedance analysis on clinical prognosis in patients undergoing hemodialysis: A retrospective study

Bioimpedance analysis (BIA) has been widely used in the evaluation of body composition in patients undergoing maintenance hemodialysis. We conducted this study to evaluate impact of phase angle (PA) and sarcopenia measured by BIA on clinical prognosis in these patients.This longitudinal retrospective study enrolled patients who underwent hemodialysis between January 2016 and March 2019. The patients were stratified into higher (> 4°) and lower (≤ 4.0°) PA groups. Sarcopenia was defined when the appendicular skeletal muscle mass was < 20 kg in men and < 15 kg in women.Of the 191 patients, 63.4% were men. The mean age was 64.2 ± 12.4 years. The lower PA group was older, had a higher proportion of women, a lower body mass index, lower albumin, cholesterol, uric acid, and phosphorus levels, and a higher incidence of history of coronary artery disease than the higher PA group. Linear regression analysis revealed that PA was significantly associated with body mass index (B = 0.18, P = .005), serum albumin (B = 0.23, P = .001), and creatinine levels (B = 0.32, P < .001). During a median follow-up of 16.7 months, 14.1% (n = 27) of patients experienced major adverse cardiovascular events and 11.0% (n = 21) died. Kaplan-Meier survival analysis showed that the higher PA group had significantly better survival, regardless of sarcopenia. Multivariate Cox analyses revealed that lower PA (0.51 [0.31-0.85], P = .010), higher IDWG (1.06 [1.01-1.12], P = .028) and C-reactive protein level (1.01 [1.01-1.02], P < .001), and a history of coronary artery disease (3.02 [1.04-8.77], P = .042) were significantly related to all-cause mortality after adjusting for other covariates.PA measured by BIA was an independent factor in the prediction of mortality in maintenance hemodialysis patients, regardless of sarcopenia. Intervention studies are needed to confirm if the improvement in PA is associated with better clinical outcome.

Impedance-derived phase angle is associated with muscle mass, strength, quality of life, and clinical outcomes in maintenance hemodialysis patients

INTRODUCTION

We aimed to evaluate the association between the phase angle and muscle mass, muscle strength, physical performance tests, quality-of-life scales, mood scales, or patient and hospitalization-free survival rates in hemodialysis (HD) patients.

METHODS

We included 83 HD patients. The patients were divided into tertiles based on phase angle value. The phase angle was measured using a bioimpedance analysis machine. Thigh muscle area per height squared (TMA/Ht2), handgrip strength (HGS), nutritional indicators, physical performance, quality-of-life, depression or anxiety status, and the presence of hospitalization or death regardless of cause were evaluated.

RESULTS

In our study, no significant differences were observed in the serum albumin level and body mass index according to tertiles of phase angle. The phase angle tertiles were associated with TMA/Ht2 and HGS. The phase angle was also associated with physical performance measurements and depression or anxiety status. Subgroup analyses according to sex, age, and diabetes mellitus showed similar trends to those of the total cohort. Furthermore, the hospitalization-free survival rate and patient survival rate were favorable in patients with high values for the phase angle.

CONCLUSION

The present study demonstrated that the phase angle is associated with muscle mass, strength, physical performance, quality-of-life scale, and hospitalization-free survival in maintenance HD patients.

Fatigue Is Not Associated with Phase Angle in Hemodialysis Patients

PURPOSE

The aim of this study was to investigate the association between fatigue and phase angle (PA) in patients with chronic kidney disease (CKD) on hemodialysis (HD).

METHODS

A cross-sectional study with older patients than 18 years diagnosed with CKD undergoing HD. From 160 (58.36±15.05 years) patients, (n=96; 60%) are men. Body mass and height were assessed using a portable scale and stadiometer, followed by body mass index (BMI) calculus. The bioimpedance electrical analysis was performed using the Bodystat QuadScan 4000. The sample size was dichotomized in two groups, using the median of our sample, either normal when PA ≥5.4º, or low when the PA <5.4º. The Chalder fatigue questionnaire was used the assess the fatigue. The multiple regression was applied to assess the association between fatigue questionnaire and PA.

RESULTS

Were considered normal PA≥5.4º (n=78, 48.8%) and low PA<5.4º (n=82, 51.2%). The patients of the PA<5.4º group are older compared to the PA≥5.4º group (63.1±15.1 vs. 53.3±13.4 years, p<0.001). There was no association between PA and fatigue score in the crude model (OR: 1.02, 95%CI: 0.96-1.08, p=0.47) and after confounding variables (OR: 1.03, CI: 0.95-1.12, p=0.43).

CONCLUSIONS

In HD patients, we found that patients with lower PA values are older. In addition, we did not find association between fatigue and PA.

Malnutrition and Sarcopenia Combined Increases the Risk for Mortality in Older Adults on Hemodialysis

Aim: Sarcopenia and malnutrition are highly prevalent in older adults undergoing hemodialysis (HD) and are associated with negative outcomes. This study aimed to evaluate the role of sarcopenia and malnutrition combined on the nutritional markers, quality of life, and survival in a cohort of older adults on chronic HD. Methods: This was an observational, longitudinal, and multicenter study including 170 patients on HD aged >60 years. Nutritional status was assessed by 7-point-subjective global assessment (7p-SGA), body composition (anthropometry and bioelectrical impedance), and appendicular skeletal muscle mass (Baumgartner's prediction equation). Quality of life was assessed by KDQoL-SF. The cutoffs for low muscle mass and low muscle strength established by the 2019 European Working group on sarcopenia for Older People (EWGSOP) were used for the diagnosis of sarcopenia. Individuals with a 7p-SGA score ≤5 were considered malnourished, individuals with low strength or low muscle mass were pre-sarcopenic, and those with low muscle mass and low muscle strength combined as sarcopenic. The sample was divided into four groups: sarcopenia and malnutrition; sarcopenia and no-malnutrition; no-sarcopenia with malnutrition; and no-sarcopenia and no-malnutrition. Follow-up for survival lasted 23.5 (12.2; 34.4) months. Results: Pre-sarcopenia, sarcopenia, and malnutrition were present in 35.3, 14.1, and 58.8% of the patients, respectively. The frequency of malnutrition in the group of patients with sarcopenia was not significantly higher than in the patients without sarcopenia (66.7 vs. 51.2%; p = 0.12). When comparing groups according to the occurrence of sarcopenia and malnutrition, the sarcopenia and malnutrition group were older and presented significantly lower BMI, calf circumference, body fat, phase angle, body cell mass, and mid-arm muscle circumference. In the survival analysis, the group with sarcopenia and malnutrition showed a higher hazard ratio 2.99 (95% CI: 1.23: 7.25) for mortality when compared to a group with no-sarcopenia and no-malnutrition. Conclusion: Older adults on HD with sarcopenia and malnutrition combined showed worse nutritional parameters, quality of life, and higher mortality risk. In addition, malnutrition can be present even in patients without sarcopenia. These findings highlight the importance of complete nutritional assessment in patients on dialysis.

Bioelectrical Impedance Analysis Derived-Phase Angle as a Pragmatic Tool to Detect Protein Energy Wasting among Multi-Ethnic Hemodialysis Patients

Protein-energy wasting (PEW) is a devastating metabolic derangement that leads to increased morbidity and mortality in hemodialysis (HD) patients. This study aimed to determine the diagnostic test accuracy of bioelectrical impedance analysis derived-phase angle (PhA) in detecting PEW among HD patients. This was a multi-centre, cross-sectional study conducted amongst 152 multi-ethnic HD patients in Klang Valley, Malaysia. PEW was assessed using the International Society of Renal Nutrition and Metabolism criteria as the reference method. PhA was measured using a multi-frequency bioelectrical impedance spectroscopy at 50 kHz. Multiple and logistic regressions were used to determine factors associated with PhA and PEW diagnosis, respectively. A receiver operating characteristics curve analysis was used to establish the gender-specific PhA cut-offs to detect PEW. PEW existed in 21.1% of the HD patients. PhA was found as an independent predictor of PEW (adjOR = 0.308, p = 0.001), with acceptable to excellent discriminative performance (adjAUC_male = 0.809; adjAUC_female = 0.719). Male patients had higher PhA cut-off compared to female patients (4.26° vs. 3.30°). We concluded that PhA is a valid and pragmatic biomarker to detect PEW in multi-ethnic Malaysian HD patients and a gender-specific cut-off is necessary, attributed to the gender differences in body composition.

Bioelectric impedance analysis for body composition measurement and other potential clinical applications in critical illness

PURPOSE OF REVIEW

Insight into body composition is of great value in the ICU. Bioelectric impedance analysis (BIA) is the most applicable bedside technique. However, bioimpedance has not been validated in the critically ill, and the interpretation of the measurements poses challenges. This review discusses the potential clinical applications of BIA and explores caveats and solutions to its use in the intensive care setting.

RECENT FINDINGS

A correlation is repeatedly found between raw impedance parameters, fluid ratios, overhydration, and adverse outcome of critical illness. However, cut-off and reference values remain elusive. Experience with BIA-guided fluid management in the ICU is limited. BIA-derived muscle mass appears a promising biomarker for sarcopenia, correlating well with CT-analysis. Body cell mass and fat-free mass provide potential use in estimation of metabolic rate, protein requirements and pharmacokinetics. Several methods of reducing bias in BIA parameters in critical illness require validation.

SUMMARY

There are currently too many uncertainties and discrepancies regarding interpretation of bioimpedance in critical illness, to justify therapeutic consequences. However, there are several promising areas of research, concerning some of the most urgent clinical problems in intensive care, emphasizing the need to evaluate further the use and interpretation of bioimpedance in the intensive care setting.

Predicational ability of phase angle on protein energy wasting in kidney disease patients with renal replacement therapy: A cross-sectional study

OBJECTIVE

To investigate the ability of phase angle (PA) and body composition for predicting protein energy wasting (PEW) in renal replacement therapy (RRT) patients.

METHODS

Renal replacement therapy (RRT) patients were enrolled in this study. Body composition was measured by direct segmental multi-frequency biolectrical impedance analysis method (DSM-BIA); phase angle (PA), fat-free mass (FFM), fat mass (FM), mid-arm circumference (MAC), WC (waist circumference), and ECW/TBW (extracellular water/total body water) were obtained. Biochemicals (serum albumin, triglyceride, and cholesterol) were tested. PEW patients were classified according to ISRNM (The International Society of Renal Nutrition and Metabolism) criteria. Cutoff value of PA and related variables was calculated by ROC analysis. The ability of body composition variables as indicators to predict PEW was evaluated.

RESULTS

Sixty-four patients were enrolled in this study. Thirty-three patients (52.6%) were males, and forty (62.5%) patients were diagnosed with PEW. The ROC curve showed that the optimal cutoff values of PA, FFMI (fat-free mass index), MAC, WC, and BMI for PEW risk were 4.45°, 16.71, 29.7 cm, 86.4 cm, and 21.1 kg/m2, respectively. These indicators showed significant association with PEW; meanwhile, the PA and MAC can be used as the predictors for PEW with OR 6.333 (95% CI, 1.956-20.505) and 3.267 (95% CI, 1.136-9.394), respectively. Both groups have a lower BUN/Cr ratio (<20).

CONCLUSION

In the RRT patients, over than 60% patients were diagnosed with PEW. PA, MAC, and other body composition can be used as the independent indicators for predicting PEW in renal replacement therapy kidney disease patients.

The relevance of whole or segmental body bioelectrical impedance phase angle and physical performance in adolescent athletes

Objective. The physical condition of athletes can be assessed easily and quantitatively using objective indicators. Bioelectrical impedance measures the phase angle (PA), representing hydration and cell function, and is a potential clinical indicator of physical condition. This study aimed to investigate the association between PA and physical performance in adolescent athletes.Approach. Overall, 170 adolescent athletes underwent a sports medical check-up, including body composition measurements and physical performance tests. Whole-body and segmental PAs (arm and leg) were determined based on body composition values. Isometric grip power and knee isokinetic muscle strength were measured as parameters of muscle strength. Counter movement jump height and squat jump height were measured as jump parameters. Associations between PA and each muscle strength or jump parameters were analysed using Pearson product-moment correlation coefficient or Spearman's rank correlation coefficient.Main results. Whole-body and upper limb PAs were highly correlated with grip power (r= 0.70-0.80). Whole-body and lower limb PAs were correlated with knee isokinetic muscle strength (r= 0.43-0.59). Whole and all segmental PAs were correlated with counter movement jump height (r= 0.46-0.57) and squat jump height (r= 0.42-0.52).Significance. PA can be used to monitor physical condition and sports performance in adolescent athletes. Segmental PAs can help assess the condition of the corresponding body part.

Phase angle values, a good indicator of nutritional status, are associated with median value of hemoglobin rather than hemoglobin variability in hemodialysis patients

Background

Our aim was to elucidate whether Hb variability affects nutritional status in HD patients.

Methods

This study included chronic HD patients (n = 76) with available monthly Hb levels up to 24 months prior to the body composition monitoring (BCM) measurement. The parameters obtained in the BCM included body mass index (BMI), lean tissue index (LTI), fat tissue index (FTI), body cell mass index (BCMI), overhydration/extracellular water ratio (OH), and phase angle (PhA). The coefficient of variation (Hb-CV), standard deviation (Hb-SD), and range of Hb (Hb-RAN) were used as indexes of Hb variability. In addition, minimum (Hb-Min), maximum (Hb-Max), average (Hb-Avg), and median (Hb-Med) Hb levels (g/dL) were analyzed.

Results

There were no significant differences in clinical, biochemical, and nutritional indexes based on the Hb-CV level. Compared to patients with an Hb-Med ≤ 10.77, those with an Hb-Med >10.77 had higher albumin levels, total iron-binding capacity (TIBC), and PhA and lower average weekly prescribed darbepoetin. Age, female sex, OH, and darbepoetin dosage were negatively correlated with PhA. Serum albumin, phosphorus, TIBC, Hb-Med, and Hb-Avg were positively correlated with PhA. In multiple linear regression analysis, PhA was positively associated with Hb-Med and serum albumin level, whereas PhA was negatively associated with age and female sex. The area under the curve (AUC) of Hb-Med was 0.665 (p = 0.040) in predicting PhA >5.00°

Conclusions

PhA was not affected by indexes of Hb variability, whereas PhA was associated with Hb-Med in chronic HD patients.

Relationship of phase angle and peak torque of knee extensors with the performance in six-minute step test in haemodialysis patients

BACKGROUND

Chronic kidney disease is a systemic disease affecting not only renal function, but also endocrine, cardiovascular, and skeletal muscle systems, with broad impact on functionality. Therefore, the assessment of body composition, peripheral muscle function, and exercise tolerance is also of great importance in this population. In addition, the development of reliable strategies that use feasible tools in clinical practice is of great importance in the functional diagnosis, clinical management and prescription of physical activity.

OBJECTIVE

To assess the relationship between phase angle and peak torque of knee extensors with the performance in six-minute step test of patients with chronic kidney disease undergoing haemodialysis.

METHODS

Observational and cross-sectional study at Haemodialysis Centre of Sírio-Libanês Hospital. The evaluations took place 3 days before the haemodialysis sessions. On the first day, patients underwent anthropometric evaluation and biochemical tests (lactate, urea, creatinine, albumin, ferritin and growth factor similar to insulin type 1 [IGF1]). On the second day, performed electrical bioimpedance and exercise tolerance assessed using the six-minute step test. On the last day, the evaluation of knee extensor muscles strength using isokinetic dynamometry was performed.

RESULTS

Eighteen subjects were included, with a mean age of 62.3 ± 17.6 years. A positive linear correlation was observed between the phase angle, derived from the electrical bioimpedance, and the performance in six-minute step test in these patients. It was also possible to observe a linear correlation between phase angle and IGF1, handgrip strength, peak torque of knee extensors and quality of life questionnaire. The peak torque of knee extensors also presented a linear correlation with IGF1, the performance in six-minute step test and mal-nutrition and inflammation score.

CONCLUSION

Phase angle and peak torque of knee extensors were correlated with the performance in six-minute step test. Therefore, the phase angle seems to be an important marker of reduced peripheral muscle function and exercise tolerance in haemodialysis patients.

Bioelectrical impedance analysis-derived phase angle as a determinant of protein-energy wasting and frailty in maintenance hemodialysis patients: retrospective cohort study

Background

Phase angle (PA), measured by bioelectrical impedance analysis (BIA) has been studied as indicator of nutritional status or muscle function in hemodialysis (HD) patients. It remains unclear if the phase angle is associated protein-energy wasting (PEW) or frailty, which are common complication in hemodialysis patients. The aim of this study is to determine whether BIA-derived PA is a marker of PEW or frailty in HD patients.

Methods

This retrospective observational study included 116 adult HD patients (35% female, 64 ± 12 years of age) in a single dialysis center. Patients were classified according to the PA quartiles into four groups; 1) first quartile: PA < 3.7°, 2) second quartile: PA 3.7–4.1°, 3) third quartile: PA 4.2–4.9°and 4) forth quartile: PA ≥ 5.0°. International Society of Renal Nutrition and Metabolism (ISRNM) criteria and Japanese version of Cardiovascular Health Study (J-CHS) criteria were used to identify PEW and frailty.

Results

The lower PA group was associated with a greater risk of PEW (35% vs. 24% vs. 21% vs. 3%; p = 0.032), frailty (59% vs. 40% vs. 21% vs. 3%; p < 0.001). In multivariate logistic regression analysis, the first quartile group was at a significantly greater risk of both PEW and frailty compared with the fourth quartile group after adjusting for other confounding factors.

Conclusions

Lower PA was associated with a greater risk of PEW and frailty in HD patients.

Association of bioimpedance-derived 50-kHz phase angle as marker of body composition with electrical parameters regarding the Cole-Cole model

Our aim is to clarify the association of the bioelectrical impedance-derived 50-kHz phase angle (φ₅₀ ) with electrical parameters regarding the Cole-Cole model and clinical parameters. A total of 440 sets of bioelectrical impedance data from pre- and post-hemodialysis from 157 patients were used. Resistance at infinite frequency (R_inf ), resistance at 0 frequency (R₀ ), capacitance of the cell membrane (Cm), and a parameter for the distribution of the time constant (α) were examined as electrical parameters. Normally hydrated lean tissue mass as a percentage of the dry weight (P_NHLT ), excess fluid mass as a percentage of the dry weight (P_ExF ), body mass index (BMI), age, and sex (N_sex , 0 for male, 1 for female) were examined as clinical parameters. φ₅₀ increased with the decrease in R_inf /R₀ and α and also with the increase in Cm (multiple regression coefficients [β]: pre/post, -0.886/-0.936, -0.175/-0.212, and 0.167/0.141), which determined the ratio of intra- to extracellular fluid volume (ICV/ECV), tissue homogeneity, and total cell mass. φ₅₀ increased with an increase in P_NHLT and BMI and decrease in P_ExF , N_sex , and age (β: pre/post, 0.654/0.581, 0.466/0.412, -0.483/-0.473, -0.216/-0.154, and -0.145/-0.127). The concordance correlation coefficient between φ₅₀ for pre- and post-hemodialysis (ρ = 0.772) may be improved (ρ = 0.950) by adding a multiplication of 0.2 and P_ExF to φ₅₀ for correction. φ₅₀ may be used to estimate body composition through the association with ICV/ECV, tissue homogeneity, and total cell mass. The correction for excess fluid is essential in order to use φ₅₀ as a marker of body composition related to nutrition.

Outcomes Assessment of Sustainable and Innovatively Simple Lifestyle Modification at the Workplace - Drinking Electrolyzed-Reduced Water (OASIS-ERW): A Randomized, Double-Blind, Placebo-Controlled Trial

Oxidative stress has been associated with many diseases as well as aging. Electrolyzed-reduced water (ERW) has been suggested to reduce oxidative stress and improve antioxidant potential. This study investigated the effects of drinking ERW on biomarkers of oxidative stress and health-related indices in healthy adults. We conducted a randomized, double-blind, placebo-controlled clinical trial on 65 participants, who were allocated into two groups. Of these, 61 received intervention (32 with ERW and 29 MW [mineral water]). All participants were instructed to drink 1.5 L/day of ERW or MW for eight weeks. Biomarkers of oxidative stress and health-related indices were assessed at baseline as well as after 4 weeks and 8 weeks of intervention. Of the primary outcome variables assessed, diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential showed a significant interaction between the groups and time, with d-ROMs levels significantly decreased at 8 weeks in ERW compared to those in MW. Among the secondary outcome variables, total, visceral, and subcutaneous fat mass significantly changed over time, with a significant association observed between the groups and time. Thus, daily ERW consumption may be a potential consideration for a sustainable and innovatively simple lifestyle modification at the workplace to reduce oxidative stress, increase antioxidant potential, and decrease fat mass.

Association of Nutritional Assessment by Phase Angle With Mortality in Kidney Transplant Patients in an 8-Year Follow-Up

BACKGROUND

Phase angle is a bioimpedance analysis parameter that indirectly shows body cell mass. Its association with mortality has been shown in patients receiving dialysis treatment. However, assessment with mortality in kidney transplant recipients has not been studied previously.

METHODS

We examined 158 kidney transplant recipients who underwent bioimpedance analysis 8 years ago in a cross-sectional study. We contacted them again and investigated the presence of cardiovascular events, cancer, angina pectoris, and claudication. Data regarding mortality, graft failure, and creatinine values were collected from recipients' files.

FINDINGS

During the follow-up period, 15 recipients died, 26 lost graft function, 36 experienced cardiovascular events, and 4 developed cancer. Phase angle was significantly associated with mortality during the 8-year follow-up period of kidney transplant recipients (P < .001). The cutoff value for phase angle as a predictor of mortality was ≤5.85. Moreover, a phase angle value lower than 5.85 indicated 5.33 times higher risk of mortality.

DISCUSSION

Phase angle was a predictor of mortality in kidney transplant recipients. Since phase angle is an inexpensive, easy-to-perform, and noninvasive method, it might be considered as an additional tool to assess survival in kidney transplant recipients.