Phase angle assessment by bioelectrical impedance analysis and its predictive value for malnutrition risk in hospitalized geriatric patients

Phase angle is associated with frailty in community-dwelling older adults

OBJECTIVES

Frailty is a geriatric syndrome associated with adverse outcomes. Malnutrition and sarcopenia are conditions intertwined with frailty. Phase angle (PhA), used to evaluate nutritional status and sarcopenia, shows the cell membrane integrity and is closely related to clinical outcomes and mortality in many chronic conditions. The aim of this study was to evaluate the relationship between PhA and frailty in community-dwelling older adults.

METHODS

The study included 299 older adults admitted to a geriatric outpatient clinic. A comprehensive geriatric assessment was performed on all participants. Frailty was evaluated via the Clinical Frailty Scale, ≥4 levels were accepted as living with frailty. All participants underwent bioelectrical impedance analysis, and PhA was recorded for each participant.

RESULTS

The prevalence of frailty among the participants was 53%. The median PhA was lower in patients living with frailty than in those who were robust (5.10 [4.55-7.80] and 5.90 [3.90-6.90] degrees, respectively, and P = 0.014). Multivariable regression analysis showed that PhA was also associated with frailty in both sexes (odds ratio [OR], 0.920; P = 0.034 for men; OR, 0.81; P = 0.005 for women, respectively) independent of age, handgrip strength, nutritional status, body mass index, living alone, and burden of morbidities.

CONCLUSION

PhA calculated with bioelectrical impedance analysis was significantly associated with frailty. Further research with large samples is needed to determine whether PhA demonstrates potential utility as a biomarker for frailty.

Association between phase angle and the nutritional status in pediatric populations: a systematic review

Background and aims

Malnutrition is prevalent in pediatric populations with any disease, and it is also related to changes in body composition. In addition, recent studies have documented relationships between these changes and phase angle (PhA), an important parameter of functional nutritional assessment. PhA could be a new marker of nutritional status. Many studies have generated information about the association between PhA and malnutrition in various pathologies, although the vast majority of this information is from adult populations. In this systematic review, we answered the following question: What is the association between PhA and the nutritional status in pediatric populations?

Methods

We performed a systematic search of the Medline/PubMed and Latin American and Caribbean Health Sciences Literature databases (LILACS) databases for studies published up to October 2022. The inclusion criteria were pediatric subjects, which reported the relationship between PhA and the nutritional status with any objective nutritional indicator, and PhA was measured by electric impedance and reported at 50 kHz. We synthesized data from the studies that reported cutoff analysis of PhA with receiver operating characteristic (ROC) curves, mean PhA values presented by nutritional status strata, and correlations between PhA and nutritional status indicators. We assessed the risk of bias by using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies and the Quality Assessment for Diagnostic Accuracy Studies.

Results

Of the 126 studies we identified, 15 met the inclusion criteria. The included studies reported the association between PhA and objective indicators of nutritional status, including weight-for-age z-score (WAZ) <-1 standard deviation (SD) for malnutrition, height-for-age z-score (HAZ) for malnutrition-stunting, body mass index (BMI) for the starvation state, body mass index z-score (BMIz) and BMI for malnutrition, mid-upper arm circumference (MUAC) <11 cm for severe acute malnutrition (SAM), and fat-free mass index z-score (FFMIz) <-2 z-score for moderate malnutrition, among others. The report of these associations between PhA and nutritional status was based on cutoff points generated with ROC curve analysis or comparison of mean PhA values, which were reported stratified by the presence or absence of malnutrition, and correlations between PhA and anthropometric indicators for the evaluation of the nutritional status in the pediatric population. It was difficult to compare the studies due to the heterogeneity of the bioelectrical impedance analysis models used, how PhA was reported (standardized, percentiles, or degrees), and the anthropometric indicators used to diagnose malnutrition.

Conclusion

The early identification of malnutrition is relevant to establish the correct nutritional treatment; PhA appears to be a sensitive indicator of nutritional status and is easy to obtain. Although the results of this review are inadequate to establish PhA cutoff points associated with malnutrition in pediatric populations, in most of the studies, there was an association between PhA and objective indicators of nutritional status.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022362413, identifier: PROSPERO 2022 CRD42022362413.

Low phase angle in critically ill older patients is associated with late mortality: A prospective study

OBJECTIVES

The aim of this study was to ascertain the accuracy of phase angle (PhA) as a predictor of mortality during intensive care unit (ICU) stay (M_ICU) and at 28 (M₂₈) and 60 d (M₆₀) after ICU admission among patients aged >60 y.

METHODS

Patients aged >60 y who were under mechanical ventilation (MV) ≥48 h were included once they were hemodynamically stable. PhA was measured by single-frequency bioelectrical impedance analysis up to 48 h after admission. ICU prognostic scores, functional scale, and nutritional assessments were performed in the first 24 h. Patients were followed for 60 d after ICU admission.

RESULTS

We enrolled 102 patients into the present study. PhA was significantly higher (P < 0.001) in survivors at M_ICU, M₂₈, and M₆₀. Areas under the receiving operator characteristic curves for M_ICU, M_28, and M₆₀ were 0.77 (95% confidence interval [CI], 0.67-0.86), 0.71 (95% CI, 0.60-0.82), and 0.71 (95% CI, 0.60-0.81), respectively. The PhA cutoff to predict mortality was 3.29° for males at M_ICU, M₂₈, and M₆₀ and lower for females at M₂₈ (2.63°) and M₆₀ (3.01°). PhA better discriminated M₆₀ than conventional prognostic scores. Logistic regression showed that even after controlling for other factors, PhA was a protective factor against late mortality. Survival analysis at 60 d revealed that low PhA was associated with lower median survival (18 versus 58 d; log-rank P < 0.001).

CONCLUSIONS

Low PhA values are associated with higher late mortality and a short survival time at 60 d in critically ill older adults. Low PhA values can be considered a useful ICU prognostic score in similar populations.

Role of phase angle in older adults with focus on the geriatric syndromes sarcopenia and frailty

Age-related changes in body composition reflect an increased risk for disease as well as disability. Bioimpedance analysis is a safe and inexpensive bed side method to measure body composition, but the calculation of body compartments with BIA is hampered in older adults. Phase angle, a raw parameter derived from bioimpedance analysis, is free from calculation-inherent errors. It declines with age and disease and is highly predictive of a variety of clinical outcomes as well as mortality. This review summarizes the current evidence linking the phase angle to geriatric syndromes such as malnutrition, sarcopenia and frailty and also investigates whether the phase angle reacts to interventions. Since the majority of studies show an association between the phase angle and these geriatric syndromes, a low phase angle is not suitable to exclusively indicate a specific condition. It does not inform on the underlying cause and as such, a low phase angle mainly indicates increased risk. Phase angle decline over time is reflected by deterioration of e.g. frailty status. It reacts to physical training and detraining, but studies investigating whether these induced changes are also associated with improved outcome are missing.

The Relationship between Phase Angle, Nutrition Status, and Complications in Patients with Pancreatic Head Cancer

Phase angle (PhA), a bioimpedance parameter, is used to assess the nutrition status and body composition of patients. Patients with pancreatic head cancer often present with body composition changes that relate to adverse outcomes. PhA may be useful to evaluate prognosis in these patients, but data are deficient. We aim to explore the effects of PhA on nutrition evaluation and short-term outcome prediction in these patients. This prospective study included 49 participants with pancreatic head cancer who underwent pancreaticoduodenectomy (PD). All participants’ nutritional status and postoperative complications were assessed using nutrition assessment tools and the Clavien−Dindo classification method, respectively. Spearman correlation analyses were used to evaluate the association between PhA, nutrition status, and postoperative complications. ROC curves were generated to evaluate the ability of PhA to predict malnutrition and complications and to determine the cutoff value. The PhA values of the nutritional risk group and the malnourished group were significantly lower than those of the well-nourished group (p < 0.05). PhA positively correlated with patients’ nutrition status. Nineteen patients had postoperative complications, and the PhA value of the complication group was significantly lower than that of the non-complication group (4.94 vs. 5.47, p = 0.013). ROC curves showed that the cutoff point of PhA to predict malnutrition was 5.45 (AUC: 0.744), and the cutoff point of PhA to predict postoperative complications was 5.35 (AUC: 0.717). Our study indicates that PhA was associated with nutrition status and could be considered a nutrition assessment tool for pancreatic head cancer patients and predict the postoperative complications of these patients who have undergone PD.

Phase Angle and Handgrip Strength as a Predictor of Disease-Related Malnutrition in Admitted Patients: 12-Month Mortality

Background: Phase Angle (PhA) value measured by bioelectrical impedance analysis (BIA) could be considered a good marker of the patient’s cell mass and cellular damage. Various studies have shown that the value of PhA is associated with an increased nutritional risk in several pathologies. However, not many studies have focused on the use of PhA as a screening tool in admitted patients. The aim of this study is to evaluate the prognostic value of PhA to determine disease-related malnutrition (DRM) and the risk that this entails for mortality and length of stay (LOS). Methods: 570 patients admitted to the hospital for different causes were included in this retrospective observational study. Patients’ nutritional risk was assessed by screening tests such as the Malnutrition Universal Screening tool (MUST) and Subjective Global Assessment (SGA), in addition to non-invasive functional techniques, such as BIA and handgrip strength (HGS), 24−48 h after admission. After performing an SGA as the gold standard to assess malnutrition, PhA and SPhA values were used to determine DRM. Furthermore, both samples: malnutrition status (MS) and non-malnutrition status (NMS) were compared, with SphA-Malnutrition corresponding to a diagnosis of malnutrition. Statistical analysis of the sample was conducted with JAMOVI version 2.2.2. Results: Patients with MS had lower PhA and SPhA than patients with NMS (p < 0.001). The ROC curve analysis (AUC = 0.81) showed a cut-off point for MS for PhA = 5.4° (sensitivity 77.51% and specificity 74.07%) and AUC = 0.776 with a cut-off point for SPhA = −0.3 (sensitivity 81.74% and specificity 63.53%). Handgrip strength (HGS) was also observed to be a good predictor in hospitalized patients. Carrying out a comparative analysis between MS and NMS, length of stay (LOS) was 9.0 days in MS vs. 5.0 days in NMS patients (OR 1.07 (1.04−1.09, p < 0.001)). A low SPhA-malnutrition value (SPhA < −0.3) was significantly associated with a higher mortality hazards ratio (HR 7.87, 95% CI 2.56−24.24, p < 0.001). Conclusion: PhA, SPhA and HGS are shown to be good prognostic markers of DRM, LOS and mortality and could therefore be useful screening tools to complement the nutritional assessment of admitted patients.

Standardized Phase Angle for Predicting Nutritional Status of Hemodialysis Patients in the Early Period After Deceased Donor Kidney Transplantation

Background

This study was designed to verify whether early posttransplant standardized phase angle (SPhA) determines nutrition status of hemodialysis patients in regard to different nutritional markers and predicts handgrip strength (HGS) 6 months after kidney transplantation.

Methods

A total of 82 kidney transplant recipients on maintenance hemodialysis treatment entered the study. Nutritional status was evaluated before kidney transplantation, at the hospital discharge date, and 6 months after. We used bioelectrical impedance analysis (BIA), three different malnutrition screening tools, HGS, and anthropometric measurements. Demographic profiles and biochemical nutritional markers were collected. SPhA values, adjusted for age and BMI, were used in our study.

Results

In the early posttransplant period, kidney transplant recipients lost muscle mass, gained fat mass, and developed mostly negative SPhA, accompanied by significantly lower albumin levels. The subjects with lower than median (<-1.46) SPhA_dis [the SPhA (at discharge) adjusted for hospitalization time and the baseline SPhA] displayed lower values of albumin concentration (43.4 vs. 45.1 g/l, p = 0.010), hemoglobin (124 vs. 133 g/l, p = 0.016), GNRI (113 vs. 118, p = 0.041), and HGS (30 vs. 33 kg, p = 0.043). These patients had higher ferritin concentrations (420 vs. 258 mkmol/l, p = 0.026), longer inpatient stays (32 vs. 21 days, p < 0.001), and higher MIS scores (3 vs. 1, p = 0.001).

Conclusion

At the moment of hospital discharge, lower than the median SPhA is related to protein-energy wasting, represented as lower concentrations of nutrition biomarkers and an active inflammatory response. Higher SPhA before kidney transplantation predicts HGS 6 months after kidney transplantation, especially in women.

Nonthyroidal illness syndrome (NTIS) in severe COVID-19 patients: role of T3 on the Na/K pump gene expression and on hydroelectrolytic equilibrium

Background

Nonthyroidal Illness Syndrome (NTIS) can be detected in many critical illnesses. Recently, we demonstrated that this condition is frequently observed in COVID-19 patients too and it is correlated with the severity the disease. However, the exact mechanism through which thyroid hormones influence the course of COVID-19, as well as that of many other critical illnesses, is not clear yet and treatment with T4, T3 or a combination of both is still controversial. Aim of this study was to analyze body composition in COVID-19 patients in search of possible correlation with the thyroid function.

Methods and findings

We report here our experience performed in 74 critically ill COVID-19 patients hospitalized in the intensive care unit (ICU) of our University Hospital in Rome. In these patients, we evaluated the thyroid hormone function and body composition by Bioelectrical Impedance Analysis (BIA) during the acute phase of the disease at admission in the ICU. To examine the effects of thyroid function on BIA parameters we analyzed also 96 outpatients, affected by thyroid diseases in different functional conditions. We demonstrated that COVID-19 patients with low FT3 serum values exhibited increased values of the Total Body Water/Free Fat Mass (TBW/FFM) ratio. Patients with the lowest FT3 serum values had also the highest level of TBW/FFM ratio. This ratio is an indicator of the fraction of FFM as water and represents one of the best-known body-composition constants in mammals. We found an inverse correlation between FT3 serum values and this constant. Reduced FT3 serum values in COVID-19 patients were correlated with the increase in the total body water (TBW), the extracellular water (ECW) and the sodium/potassium exchangeable ratio (Na_e:K_e), and with the reduction of the intracellular water (ICW). No specific correlation was observed in thyroid patients at different functional conditions between any BIA parameters and FT3 serum values, except for the patient with myxedema, that showed a picture similar to that seen in COVID-19 patients with NTIS. Since the Na⁺/K⁺ pump is a well-known T3 target, we measured the mRNA expression levels of the two genes coding for the two major isoforms of this pump. We demonstrated that COVID-19 patients with NTIS had lower levels of mRNA of both genes in the peripheral blood mononuclear cells (PBMC)s obtained from our patients during the acute phase of the disease. In addition, we retrieved data from transcriptome analysis, performed on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM)s treated with T3 and we demonstrated that in these cells T3 is able to stimulate the expression of these two genes in a dose-dependent manner.

Conclusions

In conclusion, we demonstrated that measurement of BIA parameters is a useful method to analyze water and salt retention in COVID-19 patients hospitalized in ICU and, in particular, in those that develop NTIS. Our results indicate that NTIS has peculiar similarities with myxedema seen in severe hypothyroid patients, albeit it occurs more rapidly. The Na⁺/K⁺ pump is a possible target of T3 action, involved in the pathogenesis of the anasarcatic condition observed in our COVID-19 patients with NTIS. Finally, measurement of BIA parameters may represent good endpoints to evaluate the benefit of future clinical interventional trials, based on the administration of T3 in patients with NTIS.

Body Composition and Selected Nutritional Indicators in Healthy Adults-A Cross-Sectional Study

Background

Body mass composition is subject to constant change and is multifactorially determined. Its analysis in different age groups allows a better understanding of the determinants of the human organism in health and disease.

Aim

The study was aimed to conduct cross-sectional assessment of body composition and selected nutritional indicators in healthy adults.

Methods

The cross-sectional study carried out from March 2016 to April 2018 was preceded by a monthly pilot study. All 1333 adults (women 795, 59.6%) aged 20–59 included in the study were from the urban and rural area of the Podkarpackie Province (Poland). These adults were classified into four 10-year age bands. To obtain reliable assessment, selected screening (anthropometry) and in-depth (bioelectrical impedance including phase angle and bioelectrical impedance vector analysis) methods were used.

Results

In women, the proportion of individuals affected by overweight and obesity increases significantly with age, with a less pronounced trend in men, as reflected in the observed differences in individual body composition components. A slight (0.45–0.60) correlation was also observed between body mass index (BMI) and percentage of fat mass (FM %) among men with an increasing strength of the association with age, decreasing in the 50–59 years group. In the female group, the correlations described are at a much higher level (0.80 or higher). The described changes in body composition were reflected in body type from athletic to obese, measured by means of the bioelectrical impedance vector analysis (BIVA) method.

Conclusions

Age and gender significantly differentiate body composition of the adult human body. The body composition analysis should be considered as complement screening assessment method, especially as a support for the assessment of nutritional status expressed by BMI.

Body Composition Changes Following Dialysis Initiation and Cardiovascular and Mortality Outcomes in CRIC (Chronic Renal Insufficiency Cohort): A Bioimpedance Analysis Substudy

Rationale & Objective

Bioelectrical impedance analysis (BIA) provides a noninvasive assessment of body composition. BIA measures of nutritional (phase angle) and hydration (vector length) status are associated with survival among individuals with chronic kidney disease (CKD), including those receiving maintenance dialysis. However, little is known regarding changes in these parameters with CKD following the high-risk transition to maintenance dialysis.

Study Design

Observational study.

Settings & Participants

427 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, with BIA measurements performed within 1 year before and after initiation of maintenance dialysis.

Exposures

We calculated the changes in vector length and phase angle for patients with CKD transitioning to maintenance dialysis.

Outcomes

We examined the association of changes in vector length and phase angle during the transition to maintenance dialysis with risk for all-cause mortality or nonfatal myocardial infarction, stroke, or heart failure, adjusting for demographics, comorbid conditions, and nutritional parameters.

Results

Mean age was 58 ± 12 years and mean estimated glomerular filtration rate using the CKD Epidemiology Collaboration equation before dialysis initiation was 17.0 ± 8.7 mL/min/1.73 m². After covariate adjustment, mean changes in vector length and phase angle were 18 (95% CI, 7 to 30) Ω/m and -0.6  (95% CI, -1.3  to 0.1 ), respectively. Changes in both BIA parameters were not associated with risk for heart failure, stroke, myocardial infarction, or all-cause mortality: HR, 1.02 (95% CI, 0.91-1.14) per 1-SD increment in change for vector length and HR, 1.11 (95% CI, 0.88-1.41) per 1-SD increment in change for phase angle.

Limitations

Observational study, relatively small sample size.

Conclusions

In a multicenter cohort of patients with CKD who progressed to kidney failure, the transition to maintenance dialysis was associated with changes in body composition reflecting poorer cellular integrity and improved volume control. However, these longitudinal changes were not associated with adverse clinical events after dialysis initiation.

Validation of GLIM malnutrition criteria for diagnosis of malnutrition in ICU patients: An observational study

BACKGROUND & AIMS

Patients in the Intensive Care Unit (ICU) are at high risk of malnutrition. The only validated malnutrition assessment tool is the Subjective Global Assessment (SGA). The Global Leadership Initiative on Malnutrition (GLIM) is a new malnutrition assessment tool. The present study compares the nutrition-related parameters of the following tools: GLIM tool, SGA, Phase Angle (PA), Low Fat-Free Mass Index (FFMI), and Patient- and Nutrition-Derived Outcome Risk Assessment score (PANDORA), in an attempt to validate an objective tool.

METHODS

Eighty-four ICU patients were included. The tools mentioned above were assessed for their validity in diagnosing malnutrition. All patients were defined as suffering from acute disease and received medical nutrition therapy. To evaluate whether there is a correlation between the GLIM criteria, SGA, PA, and low FFMI, we compared the SGA, PA, and low FFMI to the GLIM criteria using Spearman correlation coefficients and a Chi-square test. Also, a Mann-Whitney U test was used to test the mean differences between the GLIM criteria and the PANDORA. The area under the curve (AUC) of the proposed parameters was evaluated for diagnosis of malnutrition to seek cutoff points that yield good sensitivity and specificity.

RESULTS

Mean age was 50 ± 20 years, BMI 25.3 ± 5.1 kg/m², APACHE II 20.5 ± 7.7, PANDORA score 32 ± 8.5. GLIM malnutrition criteria were significantly correlated with the gold standard SGA assessment and with low FFMI, with PA (Phase Angle), and with the PANDORA score. The area under the curve, by using the ROC curve analysis for GLIM criteria stratified by the SGA results, was 0.85 (P < 0.001). Sensitivity was 85%, and specificity 79%. However, when comparing the low FFMI, PA, and PANDORA to the GLIM criteria, the ROC curve analysis results were considered poor rank.

CONCLUSIONS

The SGA malnutrition assessment highly validated the GLIM criteria framework combined with the two-criteria diagnosis of malnutrition with a high level of precision. The GLIM malnutrition assessment seems to be acceptable in the ICU setting.

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.

Effects of using the MyFood decision support system on hospitalized patients' nutritional status and treatment: A randomized controlled trial

BACKGROUND & AIMS

Compliance to guidelines for disease-related malnutrition is documented as poor. The practice of using paper-based dietary recording forms with manual calculation of the patient's nutritional intake is considered cumbersome, time-consuming and unfeasible among the nurses and does often not lead to appropriate nutritional treatment. We developed the digital decision support system MyFood to deliver a solution to these challenges. MyFood is comprised of an app for patients and a website for nurses and includes functions for dietary recording, evaluation of intake compared to requirements, and a report to nurses including tailored recommendations for nutritional treatment and a nutritional care plan for documentation. The study aimed to investigate the effects of using the MyFood decision support system during hospital stay on adult patients' nutritional status, treatment and hospital length of stay. The main outcome measure was weight change.

METHODS

The study was a parallel-arm randomized controlled trial. Patients who were allocated to the intervention group used the MyFood app during their hospital stay and the nurses were encouraged to use the MyFood system. Patients who were allocated to the control group received routine care.

RESULTS

We randomly assigned 100 patients (51.9 ± 14 y) to the intervention group (n = 49) and the control group (n = 51) between August 2018 and February 2019. Losses to follow-up were n = 5 in the intervention group and n = 1 in the control group. No difference was found between the two groups with regard to weight change. Malnutrition risk at discharge was present in 77% of the patients in the intervention group and 94% in the control group (p = 0.019). Nutritional treatment was documented for 81% of the patients in the intervention group and 57% in the control group (p = 0.011). A nutritional care plan was created for 70% of the intervention patients compared to 16% of the control patients (p < 0.001).

CONCLUSIONS

The intervention had no effect on weight change during hospital stay. A higher proportion of the patients in the control group was malnourished or at risk of malnutrition at hospital discharge compared to the patients in the intervention group. The documentation of nutritional intake, treatment and nutritional care plans was higher for the patients using the MyFood system compared to the control group. This trial was registered at clinicaltrials.gov (NCT03412695).

Lower Phase Angle Measured by Bioelectrical Impedance Analysis Is a Marker for Increased Mortality in Incident Continuous Ambulatory Peritoneal Dialysis Patients

OBJECTIVE

Phase angle (PA) determined by bioelectrical impedance analysis has been suggested to be a predictor of death in a variety of disease conditions, but its associations with outcomes have not yet been assessed in a large continuous ambulatory peritoneal dialysis (CAPD) patient cohort. The aim of the present study was to examine the association of PA with risks for all-cause and cardiovascular death in patients treated with CAPD.

METHODS

Incident CAPD patients were enrolled from January 1, 2010 to December 31, 2015 and were followed until December 31, 2017. Multifrequency bioelectrical impedance analysis was conducted in the morning with patients in a fasting state. Multivariable linear regression analyses were performed to study the relationships between PA and other variables. Cox proportional hazard models were used to evaluate the association between PA and mortality.

RESULTS

A total of 760 incident CAPD patients were enrolled in this study. Patients have a median PA value of 4.59° ranging from 2.30° to 7.22°. Aging, presence of diabetes mellitus, and fluid overload were independently associated with lower PA, whereas male sex, higher body mass index, higher serum levels of albumin and creatinine, and better residual renal function were independently associated with higher PA in a multivariable linear regression model. A total of 125 (16.4%) patients died during a median follow-up of 42 months. In the Cox model with adjustment for confounders, PA was significantly associated with all-cause and cardiovascular mortality in incident CAPD patients (hazard ratio, 0.584; 95% confidence interval, 0.403 to 0.844, P = .004; hazard ratio, 0.597; 95% confidence interval, 0.359 to 0.993, P = .047, respectively).

CONCLUSIONS

PA reflected a combined dimension of the illness including deranged hydration status and nutritional status. Lower PA was associated with both all-cause and cardiovascular death in patients with CAPD.

Bioelectrical Impedance Analysis for Prediction of Early Complications after Gastrectomy in Elderly Patients with Gastric Cancer: the Phase Angle Measured Using Bioelectrical Impedance Analysis

Purpose

Phase angle obtained using bioelectrical impedance analysis (BIA) provides a relatively precise assessment of the nutritional status of elderly patients. This study aimed to evaluate the significance of phase angle as a risk factor for complications after gastrectomy in elderly patients.

Materials and Methods

We evaluated 210 elderly patients (aged ≥65 years) who had undergone gastrectomy for gastric cancer between August 2016 and August 2017. The phase angle cutoff value was calculated using receiver operating characteristic curve analysis according to sex. A retrospective analysis regarding the correlation between early postoperative complications and well-known risk factors, including the phase angle, was performed.

Results

Multivariate analysis revealed that the presence of two or more comorbidities (odds ratio [OR], 3.675) and hypoalbuminemia (OR, 4.059) were independent risk factors for overall complications, and female sex (OR, 2.993) was independent risk factor for severe complications. A low phase angle (OR, 2.901 and 4.348, respectively) and total gastrectomy (OR, 4.718 and 3.473, respectively) were independent risk factors for both overall and severe complications.

Conclusions

Our findings show that preoperative low phase angle predicts the risk of overall and severe complications. Our findings suggest that BIA should be performed to assess the risk of postoperative complications in elderly patients with gastric cancer.

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

OBJECTIVE(S)

To explore the validity of using bioelectrical impedance analysis (BIA)-derived 50 kHz phase angle (PhA) in predicting protein-energy wasting (PEW) in Chinese maintenance hemodialysis (MHD) patients.

DESIGN AND METHODS

The design was a cross-sectional study. A total of 173 of MHD patients and 173 healthy adults were enrolled in the study. The prevalence of PEW in patients was performed by the International Society of Renal Nutrition and Metabolism criteria. The PhA, body cell mass, fat mass, body fat percentage, fat-free mass, and extracellular water/total body water were measured by InBody S10 body composition analyzer. The biochemical indices and anthropometric measurements were assessed using the way published elsewhere. The PhA, other values of BIA and its relationship with age, visceral protein, anthropometric measurements of the MHD patients were compared with the healthy group. The independent variables for predicting PEW and its cutoff values were explored using logistic regression model and receiver operating characteristic curve analysis, respectively.

RESULTS

The MHD patients' PhA value was significantly lower than the healthy group (4.89°± 1.19 vs. 6.32°± 2.23, P < .01). A total of 34.1% MHD patients with PEW had significantly lower PhA values compared with well-nourished patients (P < .05). The PhA decreased more significantly with age in MHD (r = -0.35, P < .001), compared with controls (r = -0.26, P < .001). The PhA values were positively associated with nutritional indices related to serum albumin, prealbumin, fat-free mass, and mid-arm muscle circumference. PhA values were not associated significantly with fat mass and body fat percentage (P > .05). Multivariate logistic regression analysis showed that PhA and body mass index were independent predictors of PEW, but the PhA was the stronger predictor (odds ratio = 4.48, P < .05). Receiver operating characteristic curve analysis suggested that the optimal PhA cutoff value to predict PEW was 4.6°.

CONCLUSIONS

BIA-derived PhA appears to be a useful bioelectrical marker for predicting PEW in Chinese hemodialysis patients with a cutoff value of 4.6°.

Bioelectrical Impedance Analysis Measures and Clinical Outcomes in CKD

RATIONALE & OBJECTIVE

Bioelectrical impedance analysis (BIA) provides a noninvasive assessment of body composition. BIA measures of cell integrity (phase angle) and hydration (vector length) have been associated with mortality among patients receiving dialysis. Whether these measures are associated with clinical outcomes in patients with chronic kidney disease (CKD) is unknown.

STUDY DESIGN

Observational study.

SETTINGS & PARTICIPANTS

We studied 3,751 participants with CKD in the prospective multicenter Chronic Renal Insufficiency Cohort (CRIC) who had baseline single-frequency BIA performed.

PREDICTORS

Predictors included phase angle and vector length, which were calculated from measurements of resistance and reactance from BIA. We ranked phase angle and vector length into quartiles and compared the 2 narrower quartiles of phase angle and shorter quartiles of vector length with the 2 upper quartiles.

OUTCOMES

Mortality, heart failure, atherosclerotic cardiovascular disease, and progression of CKD (30% decline in estimated glomerular filtration rate or end-stage kidney disease).

ANALYTIC APPROACH

We tested associations of phase angle and vector length with risks for mortality and progression of CKD using Cox proportional hazard models and the association with heart failure and atherosclerotic cardiovascular disease using Fine and Gray models. All models were adjusted for demographics, comorbid conditions, and kidney function.

RESULTS

Mean phase angle and vector length were 6.6°±1.8° and 470 ± 96 Ω/m, respectively. Relative to phase angle ≥ 6.40o, narrower phase angle (<5.59o) was significantly associated with mortality (HR, 1.31; 95% CI, 1.09-1.58). Relative to vector length ≥ 459 Ω/m, shorter vector length (<401 Ω/m) was significantly associated with heart failure (HR, 1.28; 95% CI, 1.01-1.61). Neither measure was associated with atherosclerotic cardiovascular disease or a composite renal end point.

LIMITATIONS

Observational study.

CONCLUSIONS

Adjusted for key confounders, BIA-derived measures of cellular integrity and tissue hydration were significantly associated with death and incident heart failure, respectively.

Phase Angle as a Biomarker for Frailty and Postoperative Mortality: The BICS Study

Background Phase angle (PA) is a bioimpedance measurement that is determined lean body mass and hydration status. Patients with low PA values are more likely to be frail, sarcopenic, or malnourished. Previous work has shown that low PA predicts adverse outcomes after cardiac surgery, but the effect of PA on survival has not previously been assessed in this setting. Methods and Results The BICS (Bioimpedance in Cardiac Surgery) study recruited 277 patients undergoing major cardiac surgery at 2 university-affiliated hospitals in Montreal, QC, Canada. Bioimpedance measurements as well as frailty and nutritional assessments were performed preoperatively. The primary outcome was all-cause mortality. Secondary outcomes were 30-day mortality, postoperative morbidity, and hospital length of stay. There were 10 deaths at 1 month of follow-up and 16 deaths at 12 months of follow-up. PA was associated with age, sex, body mass index, comorbidities, and frailty, as measured by the Short Physical Performance Battery and Fried scales. After adjusting for Society of Thoracic Surgeons-predicted mortality, lower PA was associated with higher mortality at 1 month (adjusted odds ratio, 3.57 per 1° decrease in PA ; 95% confidence interval, 1.35-9.47) and at 12 months (adjusted odds ratio, 3.03 per 1° decrease in PA ; 95% confidence interval, 1.30-7.09), a higher risk of overall morbidity (adjusted hazard ratio, 2.51 per 1° decrease in PA ; 95% confidence interval, 1.32-4.75), and a longer hospital length of stay (adjusted β, 4.8 days per 1° decrease in PA ; 95% confidence interval, 1.3-8.2 days). Conclusions Low PA is associated with frailty and is predictive of mortality, morbidity, and length of stay after major cardiac surgery. Further work is needed to determine the responsiveness of PA to interventions aimed at reversing frailty.

Body composition predicts clinical outcome in patients with intestinal failure on long-term home parenteral nutrition

BACKGROUND & AIMS

Patients with chronic intestinal failure (CIF) are at risk of altered body composition and impaired muscle function, which may negatively affect clinical outcome. The aim of this study was to investigate the predictive value of body composition and muscle strength in relation to clinical outcome in CIF patients on long-term home parenteral nutrition (HPN).

METHODS

This was an observational cohort study comprising 77 clinically stable patients with CIF on HPN (>12 months). At inclusion, we recorded demographic data and information regarding anthropometry, body composition assessed by bioelectrical impedance and muscle strength by hand grip strength. Number of yearly hospital readmissions and length of hospital stay (LOS) as well as all-cause mortality characterized clinical outcome. Assessment parameters were categorized according to normative reference values.

RESULTS

The average number of readmissions was 2.0 ± 1.8 per year and the average LOS was 23.2 ± 23.6 days. In univariate analysis phase angle (PA, p = 0.009) and handgrip strength (HGS, p = 0.012) were associated with the number of readmissions. Multivariate analysis confirmed the independence and significance of the association for PA (coefficient -0.5 [95% CI; -0.9 to -0.2]; p = 0.007). In addition, PA was associated with LOS in univariate analysis (p = 0.019), while none of the remaining parameters were significantly associated with LOS. During the follow-up period (median 24.3 months), 16 (20.8%) patients died and the cumulative mortality rate was 14.3% after two years. Fat free mass index (FFMI) below normal (Hazard Ratio 3.9 [95% CI; 1.1-14.1]; p = 0.04) and PA below normal (Hazard Ratio 5.3 [95% CI; 1.6-17.5]; P = 0.007) were identified as independent risk factors for mortality.

CONCLUSIONS

Phase angle significantly predicted number of readmissions, length of hospital stay and mortality in patients with intestinal failure on long-term parenteral nutrition, while fat free mass index only predicted mortality.

Assessment of adult malnutrition and prognosis with bioelectrical impedance analysis: phase angle and impedance ratio

PURPOSE OF REVIEW

Malnutrition affects prognosis in many groups of patients. Although screening tools are available to identify adults at risk for poor nutritional status, a need exists to improve the assessment of malnutrition by identifying the loss of functional tissues that can lead to frailty, compromised physical function, and increased risk of morbidity and mortality, particularly among hospitalized and ill patients and older adults. Bioimpedance analysis (BIA) offers a practical approach to identify malnutrition and prognosis by assessing whole-body cell membrane quality and depicting fluid distribution for an individual.

RECENT FINDINGS

Two novel applications of BIA afford opportunities to safely, rapidly, and noninvasively assess nutritional status and prognosis. One method utilizes single-frequency phase-sensitive measurements to determine phase angle, evaluate nutritional status, and relate it to prognosis, mortality, and functional outcomes. Another approach uses the ratio of multifrequency impedance values to indicate altered fluid distribution and predict prognosis.

SUMMARY

Use of basic BIA measurements, independent of use of regression prediction models and assumptions of constant chemical composition of the fat-free body, enables new options for practical assessment and clinical evaluation of impaired nutritional status and prognosis among hospitalized patients and elders that potentially can contribute to improved patient care and clinical outcomes. However, these novel applications have some technical and physiological limitations that should be considered.