The validity of bioelectrical impedance analysis in estimating total body water in patients with cirrhosis

Low vitamin D levels accelerates muscle mass loss in patients with chronic liver disease

Sarcopenia frequently and progressively occurs in patients with chronic liver disease. This study aimed to clarify the relationship between vitamin D levels and muscle mass loss. A total of 166 patients with chronic liver disease were enrolled in this study. Skeletal muscle mass index (SMI) was measured by bioelectrical impedance analysis at baseline and after 1 year. The rate of change in SMI from baseline after 1 year was calculated: ΔSMI (%) = [(1-year SMI - baseline SMI) / baseline SMI] × 100. Muscle mass loss was defined as ΔSMI ≤ -2%. The median 25-hydroxyvitamin D was 15.2 (11.2-19.3) ng/mL. The median SMI were 6.8 (5.9-7.8) kg/m2 at baseline and 6.7 (5.9-7.6) kg/m2 after 1 year. The median ΔSMI was -1.23% (-2.21% to 1.61%). Multivariate analysis identified low 25-hydroxyvitamin D as an independent factor associated with muscle mass loss. The optimal cut-off value of 25-hydroxyvitamin D to predict muscle mass loss was 12.7 ng/mL. Muscle mass loss was found in 56.4% v.s. 18.0% of patients with 25-hydroxyvitamin D < 12.7 vs. ≥ 12.7 ng/mL, respectively (p = 9.01 × 10-7); with the highest incidence in patients with non-alcoholic fatty liver disease (NAFLD). Specifically, patients with NAFLD and 25-hydroxyvitamin D < 12.7 ng/mL had a significantly higher incidence of muscle mass loss than those with ≥ 12.7 ng/mL (p = 1.23 × 10-3). Low vitamin D levels are associated with muscle mass loss after 1 year in patients with chronic liver disease, especially NAFLD.

Applied nutritional investigation The clinical application value of the extracellular-water-to-total-body-water ratio obtained by bioelectrical impedance analysis in people with advanced cancer

OBJECTIVES

Body-composition analysis using bioelectrical impedance analysis is gradually becoming more widely used in clinical practice. The ratio of extracellular water (ECW) to total body water (TBW) is thought to be related to the prognosis of a variety of diseases. However, its performance in people with advanced cancer deserves further discussion.

METHODS

A retrospective analysis was performed on 784 people with advanced cancer. Anthropometric indicators, serologic indicators, nutritional status, health-related quality of life, and body composition were analyzed. Participants were grouped into two groups according to ECW/TBW ratio. We used t tests and χ² tests to analyze differences between the groups. Univariate and multivariate Cox regressions were conducted to analyze the factors influencing overall survival. Logistic regression was used to analyze the related factors of malnutrition, and linear regression for factors of health-related quality of life.

RESULTS

Age, body mass index, Patient-Generated Subjective Global Assessment score, Karnofsky Performance Status questionnaire score, skeletal muscle mass index, and fat-free mass index were statistically different between the non-overhydrated and overhydrated groups. Univariate and multivariate Cox regression models showed that an ECW/TBW ≥ 0.40 is a risk factor for poor prognosis in people with advanced cancer (hazard ratio = 1.511; 95% confidence interval, 1.103-2.070; P = 0.010). Subgroup analyses were next conducted according to tumor type, with ECW/TBW ≥ 0.40 emerging as a risk factor for poor prognosis for people with advanced breast cancer and advanced gastric cancer. Logistic regression showed that ECW/TBW ≥ 0.40 is a risk factor for malnutrition in people with advanced cancer (odds ratio = 1.988; 95% confidence interval, 1.049-3.767; P = 0.035). The univariate and multivariate linear regression models showed that the ECW/TBW ratio is an influencing factor for health-related quality of life in the domains of physical functioning, role functioning, and constipation.

CONCLUSION

We found that in people with cancer, an ECW/TBW ≥ 0.40 was a risk factor for malnutrition and lower health-related quality of life, and in people with advanced cancer, it was a risk factor for poor prognosis.

Phase Angle From Bioelectrical Impedance for the Assessment of Sarcopenia in Cirrhosis With or Without Ascites

BACKGROUND AND AIMS

Skeletal muscle index (SMI) from computed tomography (CT) reliably assesses sarcopenia, however, it is expensive and involves serial radiation exposure. Phase angle (PhA) from bioimpedance analysis (BIA) is a noninvasive, low cost, bedside nutritional tool used to monitor changes to nutritional interventions. We aimed to compare the performance of PhA with SMI to assess sarcopenia in cirrhosis.

METHODS

Ambispective cohort study. Consecutive patients with cirrhosis and available images from abdominal CT scan were included. Monofrequency BIA was performed within 2 weeks CT. Spearman's correlation, ROC curve, and survival analysis with Kaplan-Meier, Cox and competing-risk regression were performed.

RESULTS

136 patients were included with a mean age of 54.5 years (60% female). Most had decompensated disease (66%) with ascites in 47%, and a mean MELD of 14 ± 6. We found positive correlations between SMI and PhA (r = 0.58 , P < .001), irrespective of the presence of ascites. The AUROC of PhA-sarcopenia in all patients was 0.702; (0.748 in males,0.677 in females). The best cutoffs of PhA for diagnosing sarcopenia were ≤5.6° in males and ≤5.4° in females. SMI and PhA were significantly associated with survival in Kaplan-Meier curves. In multivariable analyses, SMI was outperformed by age and MELD, whereas PhA remained independently associated with mortality. Considering transplantation as a competing risk, regression analysis showed both SMI and PhA to be independent predictors of mortality (sHR:0.95 [0.90-0.99] and sHR:0.61 [0.42-0.88]).

CONCLUSION

PhA moderately correlates with SMI for the identification of sarcopenia in patients with cirrhosis. However, its prognostic accuracy is comparable to that of SMI, and it is not influenced by ascites.

Effects of volume status on body composition in incident peritoneal dialysis patients

BACKGROUND

Inadequate fluid removal or high water intake leads to overhydration, which results in malnutrition. The aim of the present study was to evaluate the effects of volume status on body composition in incident peritoneal dialysis (PD) patients.

METHODS

All incident PD patients who survived ≥1 year after PD initiation were considered eligible. A total of 366 incident PD patients were finally included and divided into three tertiles according to the time-averaged-edema index (TA-EI). The body composition parameters measured using bioimpedance analysis included the EI, fat mass index (FMI, kg/m²), and appendicular muscle mass index (AMMI, kg/m²). dFMI and dAMMI were defined as delta values for each variable. The cutoff value for sarcopenia (SP) was defined as previously reported. Patients with AMMI below the cutoff values were defined as having SP.

RESULTS

The number of participants in the low, middle, and high tertiles was 126, 100, and 140, respectively. A high volume status was associated with high solute clearance, albumin loss, and glucose absorption through the peritoneal membrane, which led to high dialysate glucose. In addition, volume status was inversely associated with increases in AMMI, but was not associated with changes in FMI. SP as a categorical variable was positively associated with a high volume status. On subgroup analyses, TA-EI had the greatest negative correlation coefficients for dAMMI.

CONCLUSION

Overhydration in PD patients was associated with decrease in muscle mass indices and the development of SP.

Nutritional assessment in cirrhotic patients with hepatic encephalopathy

Hepatic encephalopathy (HE) is one of the worst complications of liver disease and can be greatly influenced by nutritional status. Ammonia metabolism, inflammation and muscle wasting are relevant processes in HE pathophysiology. Malnutrition worsens the prognosis in HE, requiring early assessment of nutritional status of these patients. Body composition changes induced by liver disease and limitations superimposed by HE hamper the proper accomplishment of exams in this population, but evidence is growing that assessment of muscle mass and muscle function is mandatory due to the role of skeletal muscles in ammonia metabolism. In this review, we present the pathophysiological aspects involved in HE to support further discussion about advantages and drawbacks of some methods for evaluating the nutritional status of cirrhotic patients with HE, focusing on body composition.

Body composition by whole-body bioelectrical impedance and prediction of clinically relevant outcomes: overvalued or underused?

BACKGROUND/OBJECTIVES

Body composition calculated using whole-body bioelectrical impedance analysis (BIA), almost invariably with height (H) and often with weight (W), can help patient management and predict clinical outcomes. This study aimed to examine the merits of this approach compared with simple anthropometry (W+H).

SUBJECTS/METHODS

Use was made of original data and validation studies based on reference body composition methods: water dilution, densitometry, dual-energy X-ray absorptiometry, and more robust methods. Prediction of clinical outcomes, including mortality and length of hospital stay, was examined in six studies of chronic obstructive pulmonary disease and a study with multiple patient groups. Vector analysis, phase angle, multi-frequency BIA and segmental impedance were not considered.

RESULTS

In a broad range of study populations, from neonates to older people, in health and disease, body composition calculated using BIA with simple anthropometry frequently offered no advantage over W+H alone, but in some situations it was superior and in others inferior. In predicting clinically relevant outcomes, the fat-free mass index (FFMI), established using BIA, had comparable and sometimes greater power than body mass index (BMI), but none of the reviewed papers used FFMI calculated from W+H or BMI to predict clinical outcomes.

CONCLUSIONS

A variable and generally weak evidence base was found to suggest that BIA with anthropometry is better at predicting body composition than simple anthropometry alone. No evidence was found from the reviewed studies that FFMI calculated from BIA and anthropometry was better at predicting clinical outcomes than FFMI calculated by simple anthropometry alone.

Elevated lipogenesis and diminished cholesterol synthesis in patients with hepatitis C viral infection compared to healthy humans

Hepatitis C virus (HCV) exerts a profound influence on host lipid metabolism. It has been suggested that the synthesis of both fatty acids (FA) and cholesterol is dysregulated in HCV but this has not been directly quantified in humans. The purpose of this study was to measure lipogenesis and cholesterol synthesis using stable isotopes in patients with HCV (n = 5) and healthy control (n = 9) subjects recruited from the University of Alberta hospital. Blood samples were taken at fasting (0 and 24 hours) and after meals over the day to mimic typical food consumption and postprandial metabolism. Isolation of free cholesterol (FC), cholesteryl ester (CE), and triglyceride (TG) from plasma and very low-density lipoproteins (VLDL) was used to measure FA and cholesterol synthesis using deuterium uptake and isotope ratio mass spectrometry. FA composition was analyzed by gas chromatography. VLDL-TG levels of polyunsaturated fatty acids (PUFA), including linoleic and linolenic acid, were lower in HCV compared to control (P < 0.05 for both). Fasting hepatic lipogenesis was significantly higher in HCV (2.80 ± 0.55%) compared to control (1.19 ± 0.27%; P = 0.03). Conversely, fasting whole-body synthesis of FC (HCV 1.64 ± 0.28% versus control 8.78 ± 1.59%) and CE (HCV 0.26 ± 0.08% versus control 1.92 ± 0.25%), as well as hepatic FC synthesis (HCV 1.68 ± 0.26% versus control 8.12 ± 0.77%) was lower in HCV (P < 0.001 for all).

CONCLUSION

These data provide evidence that lipogenesis is elevated while cholesterol synthesis is impaired in HCV, supporting previous findings from cellular and animal models. Low PUFA levels combined with elevated lipogenesis suggests a role for dietary PUFA supplementation in HCV patients.

HLA and autoimmune digestive disease: a clinically oriented review for gastroenterologists

OBJECTIVES

The human leukocyte antigen (HLA) system includes genes involved in graft-vs-host rejection and in immune response. The discovery that HLAs are associated with several diseases led to appealing developments both in basic biomedical research and in clinical medicine, and offered the opportunity to improve the understanding of pathogenesis and classification of diseases, as well as to provide diagnostic and prognostic indicators. The aim of this article is to review the association between HLA alleles and autoimmune digestive disease and its current relationship with modern HLA nomenclature and clinical practice.

METHODS

Articles dealing with the association between HLAs and autoimmune digestive disease (including celiac disease, inflammatory bowel disease, autoimmune hepatitis, sclerosing cholangitis and primary biliary cirrhosis) were searched for using Pubmed and SCOPUS databases from earliest records to January 2008.

RESULTS

The review has provided two sections. In the first, we explain the basic principles of HLA structure, function, and nomenclature, as an introduction to the second section, which describes current associations between HLA alleles and digestive diseases. The clinical implications of each HLA association are critically discussed. Actually, a clinical role for HLA typing is suggested for only a few conditions, e.g., celiac disease.

CONCLUSIONS

The knowledge of current HLA nomenclature and of its association with some digestive diseases such as celiac disease can be useful in clinical practice for diagnostic and prognostic purposes. This can avoid improper HLA typing as well as stressing the need for further studies on other possible clinical applications.

Malnutrition and hypermetabolism are not risk factors for the presence of hepatic encephalopathy: a cross-sectional study

BACKGROUND AND AIM

Hepatic encephalopathy is a frequent complication of cirrhosis. The present retrospective investigation was conducted to characterize metabolic alterations in cirrhotic patients with and without hepatic encephalopathy. We tested the hypothesis that reduced nutritional status or the degree of tissue catabolism are associated with the presence of hepatic encephalopathy.

METHODS

We investigated 223 patients with histologically confirmed nonalcoholic cirrhosis without hepatic encephalopathy and with hepatic encephalopathy (grades 1-3). To assess liver function, nutritional status, and energy metabolism, a variety of biochemical and clinical tests were performed including anthropometric measurements, bioelectrical impedance analysis, and indirect calorimetry.

RESULTS

Nutritional status and tissue catabolism were not significantly different between patients with and without hepatic encephalopathy.

CONCLUSIONS

Our data do not support the hypothesis that malnutrition or tissue catabolism are independent risk factors for the presence of hepatic encephalopathy in patients with nonalcoholic cirrhosis.

Two-component models are of limited value for the assessment of body composition in patients with cirrhosis

BACKGROUND

Most techniques for measuring body composition are based on 2-component models (2-CMs) and depend on assumptions relating to the constancy of the density (D(FFM)) and hydration fraction (HF(FFM)) of fat-free mass (FFM).

OBJECTIVES

The objectives were to determine whether these assumptions are systematically violated in patients with cirrhosis and to assess the validity of the estimates of body composition obtained in these patients by using 2-CM techniques.

DESIGN

Body composition was assessed by using a 4-component model (4-CM), which was based on data obtained from densitometry, deuterium dilution, and dual-energy X-ray absorptiometry, in 20 patients with cirrhosis who had no evidence of fluid retention and in 20 pair-matched healthy control subjects. The results were compared with those obtained by using "reference" and "bedside" 2-CM techniques.

RESULTS

The mean (+/-SD) D(FFM) was significantly lower in the patients with cirrhosis (1.091 +/- 0.008 compared with 1.100 +/- 0.006 kg/L; P < 0.001); no significant difference in HF(FFM) was observed between the patients and control subjects (74.5 +/- 2.6 compared with 73.5 +/- 2.1), although there was greater variability in the patients. Significant differences were observed in the body-composition variables obtained by using the "reference" 2-CM techniques compared with the 4-CM-the 95% limits of agreement in the patients with cirrhosis exceeded 5% body fat and 3 kg FFM; the corresponding values for the "bedside" 2-CM techniques were 11% body fat and 7.5 kg FFM.

CONCLUSIONS

Assumptions relating to the constancy of the D(FFM) and HF(FFM) are violated in patients with cirrhosis. Thus, standard 2-CM techniques provide inaccurate body composition estimates in this patient population.

Nutritional markers in liver allograft recipients

BACKGROUND

Malnutrition is common in patients with end-stage liver disease considered for transplantation, but it is unclear whether this affects the outcome after transplantation. AIM.: To determine whether the severity of malnutrition in liver transplant candidates affects outcome after transplantation.

METHODS

We did a prospective study of 61 patients with chronic liver disease accepted for transplantation.

FINDINGS

The Child-Pugh and Model for End-Stage Liver Disease (MELD) score correlated significantly but weakly with the mid-arm circumference (MAC) (rho=-0.34 and -0.31, P=0.015 and 0.025, respectively) but not with hand-grip strength, triceps skin-fold thickness (TSFT), or mid-arm muscle circumference. The Child-Pugh score but not the MELD was significantly associated with intensive therapy unit stay but not eventual outcome; there was a weak but statistically significant correlation between death and MAC (rho=+0.29, P=0.04) and TSFT (rho=+0.25, P=0.02).

CONCLUSIONS

These findings suggest that nutritional parameters and markers of disease severity do not correlate well with outcomes after transplantation.

Malnutrition is a risk factor in cirrhotic patients undergoing surgery

Cirrhotic patients may become candidates for elective and emergency surgery. This may be due to conditions requiring operations such as cholecystectomy, herniotomy, or gastrointestinal malignancies, more common in cirrhotics when compared with the general population, or to complications of the liver disease such as resectable hepatocellular carcinomas or surgical portosystemic shunts to treat portal hypertension. It has been estimated that 10% of cirrhotics undergo at least one operative procedure during the final 2 y of their lives. Many studies have documented a high risk of morbidity and mortality associated with surgical procedures in these patients, and several factors influencing the postoperative outcome have been identified. Malnutrition, which is frequently encountered in cirrhotic patients, has been shown to have an important impact on the surgical risk. A poor nutrition status also has been associated with a higher risk of complications and mortality in patients undergoing liver transplantation. Few data are available concerning the perioperative nutrition support in surgical cirrhotic patients. The results of these studies are sometimes encouraging in reporting that the nutrition therapy may improve the clinical outcome in cirrhotic patients undergoing general surgery and/or liver transplantation. The limited number of patients and their heterogeneity, however, do not allow definitive conclusions, and more research on this issue is needed.

Rapid measurement of deuterium content of breath following oral ingestion to determine body water

The ability to measure total body water accurately, non-invasively and rapidly with results that are immediately available would represent an important advance in body composition research. Flowing afterglow mass spectrometry (FA-MS) has been developed to enable immediate measurement of deuterium content in breath water from single exhalations, which when combined with oral D2O loading enables measurement of total body water. We report here its first use in normal subjects, demonstrating the dispersal kinetics of deuterium in the body by monitoring deuterium in breath water following ingestion. Ten studies were performed in six normal subjects. After obtaining baseline samples, each subject ingested 0.3 g x kg(-1) of 99.9% pure D2O. Subsequently, breath samples were obtained every 3-5 minutes until equilibration had occurred. Three distinct phases in breath deuterium content were observed: an initial immediate peak due to HDO remaining in the oral cavity, a secondary peak reflecting gastrointestinal absorption and finally equilibration with the body water. The incremental increase in breath deuterium abundance between baseline and equilibration was used to calculate the total body water. Mathematical fitting of this final equilibration phase demonstrated that the measured deuterium abundance was within 0.2% of the ideal (asymptotic) value within 2 hours in all cases. We conclude that FA-MS is a powerful new method that, when combined with oral D2O loading, enables measurement of the dispersal kinetics of HDO and the calculation of total body water within 2 hours.

Nutrition and liver diseases

Malnutrition and micronutrient deficiencies are common in patients with liver diseases. The pathogenesis of protein-energy malnutrition in cirrhosis involves many factors, including poor oral intake, malabsorption, and metabolic abnormalities similar to stress. Encephalopathy may complicate cirrhosis but is usually not caused by diet. Protein restriction is only necessary in rare patients with refractory encephalopathy. The use of branched-chain amino-acid solutions is not supported by the literature. Chronic liver diseases without cirrhosis are not usually associated with protein-energy malnutrition, but vitamin and mineral deficiencies are common, especially with significant cholestasis. Fatty liver may result from excessive triglyceride uptake and production by the liver or by a secretory defect. Therapy for fatty liver depends on its cause. Chronic total parenteral nutrition may induce fatty liver and inflammation especially in patients with short-bowel syndrome. Deficiency of choline in parenteral nutrition has been proposed as the mechanism for liver disease. Acute liver diseases such as fulminant hepatic failure or alcoholic hepatitis are considered hypercatabolic diseases and thus require prompt nutritional intervention with a high-calorie enteral or parenteral formula. In fulminant hepatic failure, low-protein, fluid-restricted formulas are recommended.

Recent developments in autoimmune liver diseases

Several diseases are regarded as autoimmune liver diseases. Apart from the cholestatic liver diseases, primary biliary cirrhosis, primary sclerosing cholangitis, these include autoimmune hepatitis, hepatitis as part of the autoimmune polyendocrine syndrome type 1 (APS-1) and particular overlap syndromes such as autoimmune cholangitis (also called antimitochondrial antibody negative primary biliary cirrhosis [PBC]), overlap syndrome chronic active hepatitis (CAH)/PBC and the overlap syndrome primary sclerosing hepatitis (PSC)/CAH. In addition, auto-antibodies may be observed during the course of chronic viral hepatitis, in particular chronic hepatitis C and D. Finally, a small number of drug-induced liver diseases is immune mediated. The following article will review our recent progress in the field of autoimmune hepatitis including APS-1 and autoimmunity in viral hepatitis and immune-mediated drug-induced liver disease.

Multi-frequency bioelectric impedance measurements for predicting body water compartments in patients with non-ascitic liver cirrhosis

We assessed total body water (TBW) and extracellular water (ECW) in thirty-four non-ascitic cirrhotics and twenty healthy controls by 2H2O and Br dilution. In the same subjects, bioelectric impedance (BI) was recorded at multiple frequencies. Body hydration was similar for controls (mean 55.6 (SD 6.7)), less-severe cirrhotics (Child-Pugh classification A; CPA; n 21, mean 56.2 (SD 6.2)) and moderately-severe cirrhotics (Child-Pugh classification B; CPB; n 13, mean 57.2 (SD 5.4)). However, intracellular water standardized per litre TBW was significantly higher in CPB subjects (mean 27.0 (SD 7.5); P < 0.01) compared with CPA (mean 21.3 (SD 10.6)) and control subjects (mean 18.0 (SD 9.8)). Published formulas for predicting TBW and ECW from BI at multiple frequencies were applied to the cirrhotics. These formulas gave accurate predictions of TBW and ECW, although standard errors of estimates were higher for CPB subjects (TBW < or = 2.5 and ECW < or = 2.1 l) than those for CPA (TBW < or = 2.0 and ECW < or = 1.8 l) and control (TBW 1.4 and ECW 0.9 l) subjects.