Bioelectrical impedance phase angle as a prognostic indicator in advanced pancreatic cancer

Adductor pollicis muscle thickness: a promising anthropometric parameter for patients with chronic renal failure

INTRODUCTION

Protein-calorie malnutrition is a prevalent disorder in chronic renal failure (CRF) and a major risk factor for increased mortality in hemodialysis (HD) patients. Although many methods have been used to assess malnutrition in CRF, the role of adductor pollicis muscle thickness (APMt) is not established yet.

AIMS

This study aimed to analyze the APMt in HD patients and to investigate the correlation between APMt and conventional anthropometric, laboratory, and bioelectrical impedance markers, as well as its association with mortality/morbidity in a period of 12 months of follow-up.

SUBJECTS AND METHODS

The study included 143 HD patients from a single facility. After dialysis, the dry weight, height, mid-arm circumference, triceps skinfold thickness, and APMt were measured. Subsequently, the body mass index, percentage of standard body weight, the mid-arm muscle circumference, and the mid-arm muscle area were calculated. Blood counts were performed for hemoglobin, creatinine, and albumin. Patients were also submitted to a single-frequency tetrapolar bioimpedance test for measuring resistance, reactance, phase angle, and percentage of body cell mass. The correlation between APMt and anthropometric, laboratory, and bioelectrical impedance parameters was calculated using Pearson's linear correlation. Multiple linear regression analysis was used to select independent risk factors to death and hospitalizations in 6 and 12 months of follow-up, among parameters selected by univariate analysis.

RESULTS

Patients were aged 52.2 ± 16.6 years (20 to 83 years) on average, 58% were men, and mean dialysis vintage was 5.27 ± 5.12 years. APMt was 11.85 ± 1.63 mm (men, 12.34 ± 1.53; women, 11.19 ± 1.51; P < .0001). APMt was positively correlated with body mass index (r = 0.37; P < .0001), mid-arm circumference (r = 0.437; P < .0001), mid-arm muscle circumference (r = 0.494; P < .0001), mid-arm muscle area (r = 0.449; P < .0001), percentage of standard body weight (r = 0.355; P = .000), creatinine (r = 0.230; P = .006), albumin (r = 0.207; P = .013), percentage of body cell mass (r = 0.293; P = .000), and phase angle (r = 0.402; P < .0001), and negatively correlated with resistance (r = -0.403; P < .0001). The APMt ≤10.6 mm was associated with a 3.3 times greater risk of hospitalization within 6 months of follow-up (OR = 3.3, 95% CI: 1.13 to 9.66; P = .029) compared with patients with an APMt >10.6 mm. The APMt was not associated with risk of death at 6 and 12 months or hospitalization within 12 months of follow-up.

CONCLUSION

This is the first study testing APMt as an anthropometric marker in HD patients. The parameter is easy to measure and does not seem to be significantly affected by variations in hydration status. The parameter was significantly correlated with markers reflecting the condition of the muscle compartment, but not with parameters estimating the fat mass. The determination of an APMt cutoff point for malnutrition in patients with CRF and its correlation with morbidity and mortality will require further investigation in clinical studies.

Determinants of bioelectrical phase angle in disease

Phase angle (PhA), a parameter of bioelectrical impedance analysis, is a well-known predictor of morbidity and mortality in various diseases. The causes of decreased PhA are, however, not yet completely understood. We therefore investigated determinants of PhA in 777 hospitalised patients in a retrospective analysis. PhA was assessed by bioelectrical impedance analysis at 50 KHz. Subjective global assessment (SGA) was used to evaluate nutritional status. Age, sex, BMI as well as nutritional status (SGA), benign or malignant disease and C-reactive protein (CRP) were investigated as potential determinants of PhA and standardised PhA (SPhA) = (observed PhA - mean PhA of reference values)/standard deviation of reference values in a general linear model regression analysis. Next to age (estimated effect size, 46·6%; P<0·0001), malnutrition (39·1%; P<0·0001) emerged as a major PhA determinant in our study population. Moreover, sex (6·4%; P<0·0001), CRP (4·4%; P<0·0001) and BMI (3·5%; P < 0·0001) exhibited a significant influence on PhA, whereas malignant disease showed no significant effect in this model. The only significant determinants of SPhA were malnutrition (85·4%; P<0·0001) and inflammation (9·6 %; P<0·0001). In conclusion, next to the established predictors, malnutrition and inflammation have a strong impact on PhA in sick individuals, which partly explains its prognostic power. When investigating the SPhA, only malnutrition and inflammation were found to be significant predictors, as a result of which the SPhA is considered a more suitable indicator of nutritional and health status.

Soft, fortified ice-cream for head and neck cancer patients: a useful first step in nutritional and swallowing difficulties associated with multi-modal management

Patients with head and neck cancer have complex swallowing and nutritional concerns. Most patients are malnourished, and treatment modalities within the aerodigestive tract have profound effects on future swallowing and nutrition. The objective of this study is to investigate whether the introduction of fortified soft ice-cream to post-operative head and neck cancer patients would increase compliance with oral-feeding regimes. Using a questionnaire study, an ice-cream machine that produces fortified soft ice-cream was introduced onto our ward, and 30 patients were asked to fill out questionnaires based on their experience in addition to their oral-feeding regime. Results indicate that overall patient satisfaction and compliance with oral-feeding regimes increased: 77% felt that the taste was excellent and also felt that it was easy to eat; 60% felt that it eased the symptoms associated with their symptoms, in particular its cold temperature. We conclude from the results that the inability of patients undergoing multi-modal treatment for upper aerodigestive tract cancer to enjoy normal foods and its effects on their quality of life is underestimated. Providing a food to that is palatable, familiar and acceptable as it is safe and nutritionally sound can increase compliance with oral-feeding regimes. The ice-cream was safe to use in the early post-operative period, especially soothing in patients undergoing upper aerodigestive radiotherapy and high in protein and calorific content. Our practice may have wider benefits, including patients with oral and oropharyngeal infections, the elderly and patients with neurological dysphagia resulting from stroke.

Standardized phase angle indicates nutritional status in hospitalized preoperative patients

There is currently no criterion standard to assess nutritional status, and different methods have been used in hospitalized patients. The aim of this study was to investigate the agreement and the association between bioelectrical impedance analysis derived by standardized phase angle (SPA) and other methods used for the nutritional assessment of body composition, metabolic status, and functional status in surgical patients. The hypothesis was that the SPA is effective for evaluating nutritional status in surgical patients; therefore, it could be used when the application of other assessment methods is not possible. The sample consisted of 125 patients (20-94 years of age) before elective gastrointestinal or hernia repair. The participants were from the Surgical Clinic 1 at the University Hospital of the Federal University of Santa Catarina, Florianópolis, SC, Brazil. Nutritional status was evaluated during the preoperative period based on the triceps skinfold thickness, mid-arm circumference, body mass index, percent weight loss, nutritional risk screening 2002 (NRS 2002), subjective global assessment (SGA), and SPA. The agreement between the SPA and the other methods was assessed with the k coefficient. The agreement between the SPA and the methods of nutritional assessment that were investigated for diagnosing malnutrition was moderate for NRS 2002 and SGA, weak for percent weight loss, and poor for triceps skinfold thickness, mid-arm circumference, and body mass index. There was a significant association between SPA and both NRS 2002 and SGA (P < .001). Our results suggest that SPA is able to indicate the risk of nutritional deficiency in the patients assessed. However, good agreement between SPA and the methods investigated was not observed.

Transmembrane potential of GlyCl-expressing instructor cells induces a neoplastic-like conversion of melanocytes via a serotonergic pathway

Understanding the mechanisms that coordinate stem cell behavior within the host is a high priority for developmental biology, regenerative medicine and oncology. Endogenous ion currents and voltage gradients function alongside biochemical cues during pattern formation and tumor suppression, but it is not known whether bioelectrical signals are involved in the control of stem cell progeny in vivo. We studied Xenopus laevis neural crest, an embryonic stem cell population that gives rise to many cell types, including melanocytes, and contributes to the morphogenesis of the face, heart and other complex structures. To investigate how depolarization of transmembrane potential of cells in the neural crest's environment influences its function in vivo, we manipulated the activity of the native glycine receptor chloride channel (GlyCl). Molecular-genetic depolarization of a sparse, widely distributed set of GlyCl-expressing cells non-cell-autonomously induces a neoplastic-like phenotype in melanocytes: they overproliferate, acquire an arborized cell shape and migrate inappropriately, colonizing numerous tissues in a metalloprotease-dependent fashion. A similar effect was observed in human melanocytes in culture. Depolarization of GlyCl-expressing cells induces these drastic changes in melanocyte behavior via a serotonin-transporter-dependent increase of extracellular serotonin (5-HT). These data reveal GlyCl as a molecular marker of a sparse and heretofore unknown cell population with the ability to specifically instruct neural crest derivatives, suggest transmembrane potential as a tractable signaling modality by which somatic cells can control stem cell behavior at considerable distance, identify a new biophysical aspect of the environment that confers a neoplastic-like phenotype upon stem cell progeny, reveal a pre-neural role for serotonin and its transporter, and suggest a novel strategy for manipulating stem cell behavior.

Bioimpedance analysis parameters and epicardial adipose tissue assessed by cardiac magnetic resonance imaging in patients with heart failure

There is increasing evidence that body composition should be considered as a systemic marker of disease severity in congestive heart failure (CHF). Prior studies established bioelectrical impedance analysis (BIA) as an objective indicator of body composition. Epicardial adipose tissue (EAT) quantified by cardiac magnetic resonance (CMR) is the visceral fat around the heart secreting various bioactive molecules. Our purpose was to investigate the association between BIA parameters and EAT assessed by CMR in patients with CHF. BIA and CMR analysis were performed in 41 patients with CHF and in 16 healthy controls. Patients with CHF showed a decreased indexed EAT (22 ± 5 vs. 34 ± 4 g/m(2), P < 0.001) and phase angle (PA) (5.5° vs. 6.4°, P < 0.02) compared to healthy controls. Linear regression analysis showed a significant correlation of CMR indexed EAT with left ventricular ejection fraction (LV-EF) (r = 0.56, P < 0.001), PA (r = 0.31, P = 0.01), total body muscle mass (TBMM) (r = 0.41, P = 0.001), fat-free mass (FFM) (r = 0.30, P = 0.02), and intracellular water (ICW) (0.47, P = 0.0003). Multivariable analysis demonstrated that LV-EF was the only independent determinant of indexed EAT (P < 0.0001). Receiver operating characteristic curve analysis indicated good predictive performance of PA and EAT (area under the curve (AUC) = 0.86 and 0.82, respectively) with respect to cardiac death. After a follow-up period of 5 years, 8/41 (19.5%) patients suffered from cardiac death. Only indexed EAT <22 g/m(2) revealed a statistically significant higher risk of cardiac death (P = 0.02). EAT assessed by CMR correlated with the BIA-derived PA in patients with CHF. EAT and BIA-derived PA might serve as additional prognostic indicators for survival in these patients. However, further clinical studies are needed to elucidate the prognostic relevance of these new findings.

Cutoff percentiles of bioelectrical phase angle predict functionality, quality of life, and mortality in patients with cancer

BACKGROUND

The bioelectrical phase angle has shown predictive potential in various diseases, but general cutoffs are lacking in the clinical setting.

OBJECTIVES

This study evaluated the prognostic value of the fifth percentile of sex-, age-, and body mass index-stratified phase angle reference values in patients with cancer with respect to nutritional and functional status, quality of life, and 6-mo mortality. In a second step, we also studied the effect of the standardized phase angle (with a z score to determine individual deviations from the population average) on these variables.

DESIGN

A total of 399 patients with cancer were studied. Phase angle was obtained with bioelectrical impedance analysis; muscle function was assessed by handgrip strength and peak expiratory flow. Quality of life was determined by the European Organization for Research and Treatment of Cancer questionnaire. Nutritional status was assessed by using Subjective Global Assessment. Survival of patients was documented after 6 mo.

RESULTS

Patients with a phase angle of less than the fifth reference percentile had significantly lower nutritional and functional status, impaired quality of life (P lt 0.0001), and increased mortality (P lt 0.001). The standardized phase angle emerged as a significant predictor for malnutrition and impaired functional status in generalized linear model regression analyses. It was also a stronger indicator of 6-mo survival than were malnutrition and disease severity in the Cox regression model (P lt 0.0001) and according to the receiver operating characteristic curve.

CONCLUSIONS

The standardized phase angle is an independent predictor for impaired nutritional and functional status and survival. The fifth phase angle reference percentile is a simple and prognostically relevant cutoff for detection of patients with cancer at risk for these factors.

Changes in nutritional status and dietary intake during and after head and neck cancer treatment

BACKGROUND

The purpose of this study was to test whether nutritional status of patients with head and neck cancer changes during and after treatment.

METHODS

Nutritional status (including body weight, lean mass, and fat mass) and dietary intake were assessed in 29 patients with head and neck cancer. Patients were assessed 1 week before, and 1 and 4 months after treatment (radiotherapy, either alone or combined with chemotherapy or surgery).

RESULTS

During treatment, body weight (-3.6 ± 5.3 kg; p = .019) and lean mass (-2.43 ± 2.81 kg; p = .001) significantly declined. Patients with sufficient intake (≥35 kcal and ≥1.5 grams protein/kg body weight) lost less body weight and lean mass than patients with insufficient intake (mean difference, -4.0 ± 1.9 kg; p = 0.048 and -2.1 ± 1.0 kg; p = .054, respectively). After treatment, only patients with sufficient intake gained body weight (2.3 ± 2.3 kg) and lean mass (1.2 ± 1.3 kg).

CONCLUSION

Patients with head and neck cancer fail to maintain or improve nutritional status during treatment, despite sufficient intake.

Preoperative body composition is influenced by the stage of operable pancreatic adenocarcinoma but does not predict survival after Whipple's procedure

OBJECTIVES

Cachexia is common in pancreatic cancer and may have an influence on longterm survival but few studies have investigated this in patients with operable tumours. Therefore, this study was carried out to document body composition status in patients with pancreatic adenocarcinoma (PCa) presenting for a Whipple's procedure (WP) and to relate the findings to histopathology and longterm survival.

METHODS

Body composition was measured 1 day before a WP for ductal PCa in 36 patients (15 men, 21 women) aged 41-81 years. Results for total body nitrogen (TBN), nitrogen index (NI), total body water (TBW), fat mass (FM) and total body potassium (TBK) were compared with results in 73 age- and sex-matched controls. Patients' survival and details from histopathology synoptic reports were documented.

RESULTS

Patients undergoing WPs had low TBK values (P < 0.001) and females had lower body fat (P = 0.007) compared with controls. Five of 36 presented with significant protein deficiency, but this was not associated with a prolonged length of stay or reduced survival. The 12 patients who had involved surgical margins had larger tumours and reduced weight (P = 0.015), FM (P = 0.001), TBN (P = 0.045), TBK (P = 0.014) and survival (P = 0.036). However, multivariate Cox's regression analysis only included FM along with vascular invasion and margin status as independent predictors of survival.

CONCLUSIONS

PCa patients undergoing a WP have reduced body fat and TBK compared with community controls while those with stage III tumours had greater deficits of fat, TBK and protein stores. However, preoperative body composition was a poor predictor of postoperative survival after pathological data were considered.

Parenteral nutrition support for patients with pancreatic cancer. Results of a phase II study

Background

Cachexia is a common problem in patients (pts) suffering from upper gastrointestinal cancer. In addition, most of these patients suffer from malabsorption and stenosis of the gastrointestinal tract due to their illness. Various methods of supplementary nutrition (enteral, parenteral) are practised. In patients with advanced pancreatic cancer (APC), phase angle, determined by bio-electrical impedance analysis (BIA), seems to be a survival predictor. The positive influence of BIA determinate predictors by additional nutrition is currently under discussion.

Methods

To examine the impact of additional parenteral nutrition (APN) we assessed outpatients suffering from APC and progressive cachexia. The assessment based on the BIA method. Assessment parameters were phase angle, ECM/BCM index (ratio of extracellular mass to body cell mass), and BMI (body mass index). Patients suffering from progressive weight loss in spite of additional enteral nutritional support were eligible for the study.

Results

Median treatment duration in 32 pts was 18 [8-35] weeks. Response evaluation showed a benefit in 27 pts (84%) in at least one parameter. 14 pts (43.7%) improved or stabilised in all three parameters. The median ECM/BCM index was 1.7 [1.11-3.14] at start of APN and improved down to 1.5 [1.12-3.36] during therapy. The median BMI increased from 19.7 [14.4-25.9] to 20.5 [15.4-25.0]. The median phase angle improved by 10% from 3.6 [2.3-5.1] to 3.9 [2.2-5.1].

Conclusions

We demonstrated the positive impact of APN on the assessed parameters, first of all the phase angle, and we observed at least a temporary benefit or stabilisation of the nutritional status in the majority of the investigated patients. Based on these findings we are currently investigating the impact of APN on survival in a larger patient cohort.

Trial registration

ClinicalTrials.gov Identifier: NCT00919659

Standardized phase angle from bioelectrical impedance analysis as prognostic factor for survival in patients with cancer

PURPOSE

Phase angle (PA), determined by bioelectrical impedance analysis (BIA), has been considered as a prognostic factor in several clinical conditions. The purpose of this study is to investigate PA, after adjusting for sex and age (standardized phase angle; SPA) as a prognostic factor for survival in cancer patients.

METHODS

A prospective study was conducted in 195 patients before the first chemotherapy course. BIA was performed in all patients and SPA was calculated. The Kaplan-Meier method was used to calculate survival. The Cox regression method was used to evaluate the independent prognostic effect of PA after adjustment for other variables.

RESULTS

Patients with SPA < -1.65 had a smaller survival rate than those with SPA ≥ -1.65 (p < 0.001). Using Cox regression, the mortality rate was higher in patients with SPA < -1.65 (RR 3.12 CI: 2.03-4.79; p < 0.001). After multivariate analysis, patients with PA < -1.65 still presented a higher mortality rate (RR 2.35 CI: 1.41-3.90; p = 0.001).

CONCLUSIONS

The present study demonstrates that PA, used as SPA, is an independent prognostic indicator in this group of cancer patients receiving chemotherapy treatment even after adjustment for other prognostic variables.

Modelling prognostic factors in advanced pancreatic cancer

Pancreatic cancer is the fifth most common cause of cancer death. Identification of defined patient groups based on a prognostic index may improve the prediction of survival and selection of therapy. Many prognostic factors have been identified often based on retrospective, underpowered studies with unclear analyses. Data from 653 patients were analysed. Continuous variables are often simplified assuming a linear relationship with log hazard or introducing a step function (dichotomising). Misspecification may lead to inappropriate conclusions but has not been previously investigated in pancreatic cancer studies. Models based on standard assumptions were compared with a novel approach using nonlinear fractional polynomial (FP) transformations. The model based on FP-transformed covariates was most appropriate and confirmed five previously reported prognostic factors: albumin, CA19-9, alkaline phosphatase, LDH and metastases, and identified three additional factors not previously reported: WBC, AST and BUN. The effects of CA19-9, alkaline phosphatase, AST and BUN may go unrecognised due to simplistic assumptions made in statistical modelling. We advocate a multivariable approach that uses information contained within continuous variables appropriately. The functional form of the relationship between continuous covariates and survival should always be assessed. Our model should aid individual patient risk stratification and the design and analysis of future trials in pancreatic cancer.

Bioelectrical impedance phase angle in clinical practice: implications for prognosis in stage IIIB and IV non-small cell lung cancer

Background

A frequent manifestation of advanced lung cancer is malnutrition, timely identification and treatment of which can lead to improved patient outcomes. Bioelectrical impedance analysis (BIA) is an easy-to-use and non-invasive technique to evaluate changes in body composition and nutritional status. We investigated the prognostic role of BIA-derived phase angle in advanced non-small cell lung cancer (NSCLC).

Methods

A case series of 165 stages IIIB and IV NSCLC patients treated at our center. The Kaplan Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle, independent of stage at diagnosis and prior treatment history.

Results

93 were males and 72 females. 61 had stage IIIB disease at diagnosis while 104 had stage IV. The median phase angle was 5.3 degrees (range = 2.9 – 8). Patients with phase angle <= 5.3 had a median survival of 7.6 months (95% CI: 4.7 to 9.5; n = 81), while those with > 5.3 had 12.4 months (95% CI: 10.5 to 18.7; n = 84); (p = 0.02). After adjusting for age, stage at diagnosis and prior treatment history we found that every one degree increase in phase angle was associated with a relative risk of 0.79 (95% CI: 0.64 to 0.97, P = 0.02).

Conclusion

We found BIA-derived phase angle to be an independent prognostic indicator in patients with stage IIIB and IV NSCLC. Nutritional interventions targeted at improving phase angle could potentially lead to an improved survival in patients with advanced NSCLC.

Bioimpedance vector analysis as a measure of muscle function

INTRODUCTION

The impedance vector produced by an alternating current in the bioimpedance analysis can be seen as a standardised test of cellular mass and function since reactance is believed to reflect the mass and integrity of cell membranes. This study investigated the association between resistance and reactance normalised for height (R/H and Xc/H), and muscle function as assessed by hand grip strength.

METHODS

363 patients (172 male, 191 female) from Berlin and Copenhagen were included in the analysis. Whole body impedance was determined by BIA 2000M (Berlin) or EFG2.0 (Copenhagen). Hand grip strength was measured with Digimax electronic hand dynamometer (Berlin) or Jamar dynamometer (Copenhagen). The general linear model was used to assess the association between R/H, Xc/H and hand grip strength.

RESULTS

We observed a significant association between the impedance parameters R/H and Xc/H and hand grip strength after adjusting for confounding variables (hand grip strength= -36.9 - 0.063 x R/H + 0.573 x Xc/H + 40.7 x Height + 0.115 x Weight - 0.09 x Age + 3.41 (gender=male) + 1.87 (Centre Berlin); Weight: P=0.04, all other coefficients: P<0.0005. r(2)=0.708).

CONCLUSIONS

The impedance parameters R/H and Xc/H are related to hand grip strength and might therefore be used as a cooperation-independent method to reproducibly assess muscle function.

Bioelectrical phase angle values in a clinical sample of ambulatory rehabilitation patients

Background

Phase angle (PhA) is derived from the resistance and reactance measurements obtained from bioelectric impedance analysis (BIA) and is considered indicative of cellular health and membrane integrity. This study measured PhA values of rehabilitation patients and compared them to reference values, measures of functional ability and serum C-reactive protein (CRP) levels to explore their utility as a clinical tool to monitor disease progression and treatment efficacy.

Methods

This cross-sectional observational study was conducted on 215 ambulatory rehabilitation patients aged 20 – 94 years. All participants had been hospitalised for a stroke, orthopaedic or other condition resulting in a functional limitation. PhA was derived from BIA analysis and functional ability characterised using the Functional Independence Measure (FIM), timed up and go (TUG) and maximal quadriceps strength (MQS). Serum levels of CRP were also collected.

Results

Stroke patients had the highest PhA (5.3°) followed by elective orthopaedic surgery (5.0°) with the other group (4.3°) significantly lower than both previous categories (p < 0.001). Ambulatory rehabilitation patients' PhA values were dependent on age and sex (p < 0.001), lower than published age matched healthy reference values (p ≤ 0.05) and similar to other hospitalised or sick groups, but also higher than values reported in critically ill patients. Patients with CRP values less than 10 mg.L^-1 had significantly (p = 0.005) higher mean PhA values. Furthermore, the highest functional status quartiles had significantly higher PhAs (p ≤ 0.04) for the FIM, MQS and TUG measures.

Conclusion

The results suggest that the phase angles of rehabilitation patients are between those of healthy individuals and seriously ill patients, thereby supporting claims that PhA is indicative of general health status. Phase angles are a potentially useful indicator of functional status in patients commencing an ambulatory rehabilitation program with a normal hydration status.

A rational approach to nutritional assessment

BACKGROUND & AIMS

Consensus regarding definitions of malnutrition and methods to assess nutritional state is lacking. We propose a definition and its operationalization.

METHODS

A definition was formulated on the basis of the pathophysiology of malnutrition, while reviewing the metabolic and physiological characteristics of different populations, considered to be malnourished. The definition was operationalized to yield measures to perform nutritional assessment.

RESULTS

Malnutrition was defined as "a subacute or chronic state of nutrition in which a combination of varying degrees of over- or undernutrition and inflammatory activity has led to a change in body composition and diminished function". Its operationalization led to four elements that may serve as the basis of nutritional assessment: (1) measurement of nutrient balance, (2) measurement of body composition, (3) measurement of inflammatory activity, and (4) measurement of muscle, immune and cognitive function. Most elements measured should be validated with gold standards; normal values should be obtained in different populations. Values obtained in people considered to be at nutritional risk should be related to outcome.

CONCLUSION

A definition is proposed that reflects the pathophysiology of malnutrition and that, when operationalized, will lead to measures reflecting this pathophysiology. Such an approach may yield comparable and reproducible rates and degrees of malnutrition in populations as well as in individuals.

Bioelectrical impedance phase angle as a prognostic indicator in breast cancer

Background

Bioelectrical impedance analysis (BIA) is an easy-to-use, non-invasive, and reproducible technique to evaluate changes in body composition and nutritional status. Phase angle, determined by bioelectrical impedance analysis (BIA), detects changes in tissue electrical properties and has been hypothesized to be a marker of malnutrition. Since malnutrition can be found in patients with breast cancer, we investigated the prognostic role of phase angle in breast cancer.

Methods

We evaluated a case series of 259 histologically confirmed breast cancer patients treated at Cancer Treatment Centers of America. Kaplan Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle independent of stage at diagnosis and prior treatment history. Survival was calculated as the time interval between the date of first patient visit to the hospital and the date of death from any cause or date of last contact/last known to be alive.

Results

Of 259 patients, 81 were newly diagnosed at our hospital while 178 had received prior treatment elsewhere. 56 had stage I disease at diagnosis, 110 had stage II, 46 had stage III and 34 had stage IV. The median age at diagnosis was 49 years (range 25 – 74 years). The median phase angle score was 5.6 (range = 1.5 – 8.9). Patients with phase angle <= 5.6 had a median survival of 23.1 months (95% CI: 14.2 to 31.9; n = 129), while those > 5.6 had 49.9 months (95% CI: 35.6 to 77.8; n = 130); the difference being statistically significant (p = 0.031). Multivariate Cox modeling, after adjusting for stage at diagnosis and prior treatment history found that every one unit increase in phase angle score was associated with a relative risk of 0.82 (95% CI: 0.68 to 0.99, P = 0.041). Stage at diagnosis (p = 0.006) and prior treatment history (p = 0.001) were also predictive of survival independent of each other and phase angle.

Conclusion

This study demonstrates that BIA-derived phase angle is an independent prognostic indicator in patients with breast cancer. Nutritional interventions targeted at improving phase angle could potentially lead to an improved survival in patients with breast cancer.

Bioelectrical impedance analysis for the evaluation of hepatic fibrosis in patients with chronic hepatitis C infection

Bioelectrical impedance analysis (BIA) is a non-invasive technique that measures electrical resistance (R) and reactance (Xc), which are then used to calculate phase angle (PA). The aim of this pilot study was to assess whether BIA can differentiate between minimal and advanced hepatic fibrosis in patients with chronic hepatitis C (HCV) infection. Twenty patients with HCV participated in this study, and were divided into minimal (Metavir 1) and advanced (Metavir 3 or 4) fibrosis groups. We obtained BIA measurements (R and Xc) in several axes and calculated PA from each pair of measurements. We found no statistically significant differences between the two groups with respect to PA, R, or Xc for the whole body, the trunk or the right upper quadrant measurements in any axis. Mean whole body PA was 7.0 and 7.1 (P = 0.9) in the minimal and advanced fibrosis groups, respectively. Bioelectrical impedance analysis did not demonstrate the ability to distinguish between minimal and advanced degrees of hepatic fibrosis in patients with chronic HCV infection.

The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

Background

Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer.

Methods

We evaluated a case series of 73 stages III and IV colorectal cancer patients. Patients were classified as either well-nourished or malnourished using the SGA. BIA was conducted on all patients and phase angle was calculated. The correlation between phase angle and SGA was studied using Spearman correlation coefficient. Receiver Operating Characteristic curves were estimated using the non-parametric method to determine the optimal cut-off levels of phase angle.

Results

Well-nourished patients had a statistically significantly higher (p = 0.005) median phase angle score (6.12) as compared to those who were malnourished (5.18). The Spearman rank correlation coefficient between phase angle and SGA was found to be 0.33 (p = 0.004), suggesting better nutritional status with higher phase angle scores.

A phase angle cut-off of 5.2 was 51.7% sensitive and 79.5% specific whereas a cut-off of 6.0 was 82.8% sensitive and 54.5% specific in detecting malnutrition. Interestingly, a phase angle cut-off of 5.9 demonstrated high diagnostic accuracy in males who had failed primary treatment for advanced colorectal cancer.

Conclusion

Our study suggests that bioimpedance phase angle is a potential nutritional indicator in advanced colorectal cancer. Further research is needed to elucidate the optimal cut-off levels of phase angle that can be incorporated into the oncology clinic for better nutritional evaluation and management.

Effects of creatine supplementation on nutritional status, muscle function and quality of life in patients with colorectal cancer--a double blind randomised controlled trial

BACKGROUND & AIM

Nutritional status frequently deteriorates during chemotherapy in cancer. This is associated with a poor outcome. Since creatine supplementation has shown promising results in various diseases, we investigated the effects of creatine on nutritional status in patients with colorectal cancer undergoing chemotherapy.

METHODS

Thirty patients with colorectal cancer undergoing chemotherapy were randomised to receive either creatine (n=16) or placebo (n=15) for 8 weeks. Body composition was determined with bioelectrical impedance analysis; muscle function by hand grip, hip flexion and knee extension strength and quality of life (QoL) was assessed by the QLQ30 questionnaire.

RESULTS

Neither muscle function, body cell mass (BCM) nor QoL improved, but phase angle, a marker of BCM and cell integrity, increased significantly in the intervention patients (5.3+/-0.3 degrees to 5.4+/-0.2 degrees , P=0.030). Evaluating patients with different chemotherapy regimens, however, only intervention patients undergoing less aggressive chemotherapy were shown to benefit, increasing phase angle (5.11+/-0.22 degrees to 5.51+/-0.30 degrees , P=0.043) as well as BCM (27.22+/-2.85 to 29.60+/-3.54kg, P=0.043).

CONCLUSION

Creatine failed to improve muscle mass or function and QoL in colorectal cancer patients but improved bioimpedance parameters that are predictive of poor outcome. Creatine might therefore be useful in patients with milder chemotherapy in order to maintain or increase BCM whereas patients undergoing aggressive chemotherapy however are not likely to benefit.

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

Evaluation of body composition provides clinically useful information in several diseases including chronic kidney disease. Bioimpedance analysis (BIA) is a simple, cheap, and noninvasive tool for monitoring body composition. We performed BIA in 451 healthy adults and 162 end-stage renal disease (ESRD) patients. Resistance (R) and reactance (Xc) values were obtained at 50-kHz frequency using a tetrapolar impedance meter. Body compartments were derived using population-specific regression equations. Phase angles (arctan Xc/R) were calculated and impedance vector distribution was determined using the RXc graph method. Compared to healthy population, ESRD patients had similar post-dialysis resistance with lower reactance and phase angle, indicating decreased soft tissue mass and inadequate ultrafiltration. BIA equations estimated decreased fat mass index and intracellular water, whereas the total body and extracellular water percentages were increased. Sex-specific reference RXc plots with 95, 75, and 50% tolerance ellipses were drawn for the healthy population. A significant difference was noted in the vector positions and 95% confidence ellipses of the two sexes and body mass indices of </=25 and >25. In conclusion, we present the reference BIA parameters for Indian population. ESRD patients show significant body compartment alterations. The RXc score graph can differentiate ESRD patient from normal controls and can be used to monitor nutrition and hydration status.

Malnutrition was associated with poor quality of life in colorectal cancer: a retrospective analysis

BACKGROUND AND OBJECTIVE

Malnutrition is a significant cause of morbidity and mortality in advanced colorectal cancer, and little is known about its relationship with quality of life (QoL). We investigated the relationship between nutritional status and QoL in colorectal cancer.

METHODS

We examined a case series of 58 stage III-IV colorectal cancer patients treated at Cancer Treatment Centers of America. Nutritional status was evaluated using laboratory measures of serum albumin, prealbumin, and transferrin, subjective global assessment (SGA) and bioelectrical impedance analysis. QoL was evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (QLQ-C30).

RESULTS

The prevalence of malnutrition, as determined by SGA, was 41% (24 of 58). Well-nourished patients had statistically significantly better QoL scores on the global, physical, and role functions compared to malnourished patients. Interestingly, the median role function score in well-nourished patients was 41.6 points higher than the corresponding score in malnourished patients, indicating a "much better" functioning from a patient's perspective. Similarly, QoL scores on multiple symptom scales were statistically significantly better among well-nourished patients.

CONCLUSION

This study suggests that malnutrition is associated with poor QoL, as measured by the QLQ-C30 in colorectal cancer.

Modelo experimental de icterícia obstrutiva: avaliação por meio da bioimpedância

OBJETIVO: A bioimpedância é um método utilizado, como medida de massa corporal, volume líquido e volume de gordura corporal. Os autores analisam a utilização e desempenho da impedância em modelo de pesquisa experimental de icterícia obstrutiva. MÉTODO: Utilizaram-se oito ratos da linhagem Wistar, que foram divididos em dois grupos de quatro animais: grupo 1(experimento) e grupo 2 (controle). No grupo 1 foi realizado ligadura do colédoco e no grupo 2 laparotomia. Realizou-se a mensuração da resistência e da reatância capacitiva com aparelho de análise de bioimpedância no pré e pós-operatórios. RESULTADOS: O estudo revelou valores médios de resistência para o grupo controle maiores do que para o experimento, mostrando uma diferença significante. Também os valores de reatância capacitiva apresentaram médias maiores no grupo controle com p<0,0001. CONCLUSÕES: A análise dos resultados permite concluir que no rato: há diferenças nos valores de impedância entre os animais do grupo controle e experimental; os valores médios de resistência e reatância capacitiva são menores no grupo experimento e que a aplicabilidade da impedância no presente modelo pode ser sugerida.

Die Bioelektrische Impedanzanalyse in der Diagnostik der Malnutrition

Malnutrition is one of the most common comorbidities in the elderly. Despite several screening and assessment tools, the diagnosis can be difficult in some cases. In the geriatric population, classical anthropometry does not help very much. For that reason there is a need for further diagnostic criteria. Bioelectrical impedance analysis (BIA) is a fast, low-cost and non-invasive method, which has shown its value in several fields of medicine. Whether this method could be a useful part in the diagnosis of malnutrition in geriatric patients, is the question of this study. In comparison with the Mini-Nutritional Assessment (MNA), serum-albumin and other diagnostic markers of malnutrition, especially the phase angle (50 kHz) of bioelectric impedance analysis showed a consistent correlation with most of the parameters. The calculation of body-fat mass and fat-free mass from bioelectrical impedance analysis is not yet sufficiently validated for geriatric patients. In this study there was no good correlation of the BIA-calculated body-fat mass and fat-free mass with the observed nutritional parameters.

Bioelectrical impedance analysis in clinical practice: a new perspective on its use beyond body composition equations

PURPOSE OF REVIEW

The bioelectrical impedance analysis is not a direct method for estimating body composition. Its accuracy depends on regression equations, and recent papers have suggested that this approach should not be used in several clinical situations. Another option is to obtain information about the electrical properties of tissues by using raw bioelectrical impedance measurements, resistance and reactance. They can be expressed as a ratio (phase angle) or as a plot (bioelectrical impedance vector analysis). This review describes their use in clinical practice.

RECENT FINDINGS

The phase angle changes with sex and age. It is described as a prognostic tool in many clinical situations. There are some controversies about considering it as a nutritional marker. Studies in burn victims and sickle-cell disease corroborate its ability to evaluate cell membrane function. Bioelectrical impedance vector analysis allows a semi-quantitative estimation of body composition from information from tissue hydration and soft-tissue mass in a plot. It can be used in healthy individuals or patients, for a population or individual evaluation of fluid imbalance or an assessment of soft-tissue mass. It has also been used as a prognostic tool in dialysis and cancer patients.

SUMMARY

The phase angle can be considered a global marker of health, and future studies are needed to prove its utility in intervention studies. Bioelectrical impedance vector analysis has increased its utility in clinical practice, even when the equations may be inaccurate for body composition analysis.