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

Physical inactivity and insufficient dietary intake are associated with the frequency of sarcopenia in patients with compensated viral liver cirrhosis

AIM

The association between sarcopenia and nutritional status is thought to be an important problem in patients with cirrhosis. In this study, we investigated whether nutritional factors were related to sarcopenia in patients with liver cirrhosis.

METHODS

The subjects were 50 patients with cirrhosis aged 41 years or older. In this study, the subjects were interviewed about their dietary habits, and their daily physical activity was surveyed using a pedometer. The skeletal muscle mass index (SMI) was calculated using the appendicular skeletal muscle mass (ASM) measured by bioelectric impedance analysis. The handgrip strength was measured using a hand dynamometer. Sarcopenia was defined by SMI and handgrip strength. The patients with cirrhosis were categorized as normal group or sarcopenia group, and the two groups were compared. Univariate and multivariate logistic regression modeling were used to identify the relevance for sarcopenia in patients with cirrhosis.

RESULTS

Height (odds ratio (OR), 5.336; 95% confidence interval [CI], 1.063-26.784; P = 0.042), energy intake per ideal bodyweight (IBW) (OR, 5.882; 95% CI, 1.063-32.554; P = 0.042) and number of steps (OR, 4.767; 95% CI, 1.066-21.321; P = 0.041) were independent relevant factors for sarcopenia. Moreover, a significantly greater number of the patients in the sarcopenia group had low values for both parameters' energy intake per IBW and number of steps.

CONCLUSION

Our results suggest that walking 5000 or more steps per day and maintaining a total energy intake of 30 kcal/IBW may serve as a reference for lifestyle guidelines for compensated cirrhotic patients.

Value of the extracellular water ratio for assessment of cirrhotic patients with and without ascites

AIMS

Ascites, which often complicates liver cirrhosis, is reported to be a factor that worsens the outcome. The aims of this study were to quantify body water compartment changes in cirrhotic patients, with and without ascites, and to elucidate the value of body water analysis for predicting the development of ascites.

METHODS

A total of 109 cirrhotic patients, with and without ascites, and 65 controls were studied. Intra- and extracellular water (ECW) in the whole body and in the arm, leg and trunk were measured using the recently developed 8-electrodes multiple-frequency bioelectrical impedance analyzer. Furthermore, patients without ascites were followed to an episode of ascites or death.

RESULTS

Patients with liver cirrhosis had significantly higher ECW ratios than controls. ECW ratios were increased in cirrhotic patients with moderate and severe disease. The ECW ratio of the trunk showed highly significant changes in cirrhotic patients with ascites. The ECW ratio correlated with age, serum albumin, and prothrombin time. A relative expansion of ECW and low albumin were predictive of further episodes of ascites (log-rank 6.94, P < 0.01). In multivariate analysis, the ECW ratio was independently associated with the development of ascites.

CONCLUSION

Liver cirrhosis was characterized by a redistribution of body water. The ECW ratio is a reliable tool for quantification of redistribution of body water and can predict the development of ascites.

Ability of new octapolar bioimpedance spectroscopy analyzers to predict 4-component-model percentage body fat in Hispanic, black, and white adults

BACKGROUND

New, vertical, 8-electrode bioimpedance spectroscopy (BIS) analyzers provide detailed body-composition and nutritional information within 2 min. This is the first report on BIS's accuracy in predicting relative fatness [percentage body fat (%BF)] in a heterogeneous sample according to a multicomponent model criterion.

OBJECTIVE

We compared %BF measurements from 2 BIS devices with those from a multicomponent model in a sample of Hispanic, black, and white adults.

DESIGN

Equal numbers of apparently healthy men and women (n = 75 of each) from each racial-ethnic group, diverse in body mass index and age, volunteered. Reference %BF (%BF(4C)) was computed by using a 4-component (4C) model with total bone mineral content obtained from dual-energy X-ray absorptiometry, body density from underwater weighing with measured residual lung volume, and total body water from traditional BIS. Estimations from InBody 720 (%BF(720)) and InBody 320 (%BF(320)) BIS analyzers were validated against %BF(4C).

RESULTS

The %BF(720) (r = 0.85, SEE = 5.19%BF) and %BF(320) (r = 0.84, SEE = 5.17%BF) correlations were significant (P < 0.05) in the men; main effects were nonsignificant. Correlations for %BF(720) (r = 0.88, SEE = 4.85%BF) and %BF(320) (r = 0.89, SEE = 4.82%BF) also were significant in the women (P < 0.05); there was a main effect for method but not race-ethnicity. There were no sex-specific overestimations or underestimations at the extremes of the distributions.

CONCLUSIONS

BIS estimates of %BF(4C) were well correlated in men and women. There were no significant methodologic differences in the men. The %BF(4C) was significantly underestimated by %BF(720) and %BF(320) in the women.

The validity of bioelectrical impedance models in clinical populations

Bioelectrical impedance analysis (BIA) is the most commonly used body composition technique in published studies. Herein we review the theory and assumptions underlying the various BIA and bioelectrical impedance spectroscopy (BIS) models, because these assumptions may be invalidated in clinical populations. Single-frequency serial BIA and discrete multifrequency BIA may be of limited validity in populations other than healthy, young, euvolemic adults. Both models inaccurately predict total body water (TBW) and extracellular water (ECW) in populations with changes in trunk geometry or fluid compartmentalization, especially at the level of the individual. Single-frequency parallel BIA may predict body composition with greater accuracy than the serial model. Hand-to-hand and leg-to-leg BIA models do not accurately predict percent fat mass. BIS may predict ECW, but not TBW, more accurately than single-frequency BIA. Segmental BIS appears to be sensitive to fluid accumulation in the trunk. In general, bioelectrical impedance technology may be acceptable for determining body composition of groups and for monitoring changes in body composition within individuals over time. Use of the technology to make single measurements in individual patients, however, is not recommended. This has implications in clinical settings, in which measurement of individual patients is important.

Bioelectrical impedance analysis-part II: utilization in clinical practice

BIA is easy, non-invasive, relatively inexpensive and can be performed in almost any subject because it is portable. Part II of these ESPEN guidelines reports results for fat-free mass (FFM), body fat (BF), body cell mass (BCM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) from various studies in healthy and ill subjects. The data suggests that BIA works well in healthy subjects and in patients with stable water and electrolytes balance with a validated BIA equation that is appropriate with regard to age, sex and race. Clinical use of BIA in subjects at extremes of BMI ranges or with abnormal hydration cannot be recommended for routine assessment of patients until further validation has proven for BIA algorithm to be accurate in such conditions. Multi-frequency- and segmental-BIA may have advantages over single-frequency BIA in these conditions, but further validation is necessary. Longitudinal follow-up of body composition by BIA is possible in subjects with BMI 16-34 kg/m(2) without abnormal hydration, but must be interpreted with caution. Further validation of BIA is necessary to understand the mechanisms for the changes observed in acute illness, altered fat/lean mass ratios, extreme heights and body shape abnormalities.

High relative fat-free mass is important for maintaining serum albumin levels in patients with compensated liver cirrhosis

AIM: In patients with liver cirrhosis, hypoalbuminemia causes edema and ascites, and a reduction in the quality of life. Since musculature is catabolized to supply amino acids for albumin synthesis in malnutritional cirrhotic patients, muscular volume is hypothesized to play an important role in albumin production. Therefore, we investigated the correlation between serum albumin levels and the fat-free mass (FFM) in cirrhotic patients.

METHODS: Fifty-seven patients (26 males and 31 females) with compensated liver cirrhosis were evaluated. Patients with edema or ascites were excluded from the study. Healthy volunteers (n = 104; 48 males and 56 females) were also evaluated as controls. FFM was measured using 5-500 kHz multifrequency bioelectric impedance analysis. To minimize the difference in FFM distribution between males and females, we introduced a new marker, relative FFM (rFFM), which represents the ratio of FFM in a patient relative to that in a volunteer of the same height. Following FFM measurement, the serum albumin levels of patients were assayed monthly.

RESULTS: In patients with active cirrhosis (alanine aminotransaminase [ALT] >50 U/L), both albumin (the difference between maximum and minimum levels) and the standard deviation of albumin levels (SD-albumin) during the observation period showed a significant correlation with rFFM. Multiple linear regression analysis using variables such as rFFM, platelet number, and serum cholesterol levels, choline esterase, albumin, bilirubin, and ALT revealed that rFFM and ALT were significant and independent factors that influenced albumin or SD-albumin in cirrhotic patients.

CONCLUSION: Our results indicate that cirrhotic patients with high rFFM showed less of a decrease in albumin levels, and that the muscle volume is one of the most important factors for maintaining serum albumins level in active cirrhosis. Exercise and protein-rich nutrition at the early stage of liver cirrhosis may be advisable for maintaining or increasing muscular volume.

Estimation of body water compartments in cirrhosis by multiple-frequency bioelectrical-impedance analysis

Estimation of total body water by measuring bioelectrical impedance at a fixed frequency of 50 kHz is useful in assessing body composition in healthy populations. However, in cirrhosis, the distribution of total body water between the extracellular and intracellular compartments is of greater clinical importance. We report an evaluation of a new multiple-frequency bioelectrical-impedance analysis technique (MFBIA) that may quantify the distribution of total body water in cirrhosis. In 21 cirrhotic patients and 21 healthy control subjects, impedance to the flow of current was measured at frequencies ranging from 4 to 1012 kHz. These measurements were used to estimate body water compartments and then compared with total body water and extracellular water determined by isotope methodology. In cirrhotic patients, extracellular water and total body water (as determined by isotope methods) were well predicted by MFBIA (r = 0.73 and 0.89, respectively). However, the 95% confidence intervals of the limits of agreement between MFBIA and the isotope methods were +/-14% and +/-9% for cirrhotics (extracellular water and total body water, respectively) and +/-9% and +/-9% for cirrhotics without ascites. The 95% confidence intervals estimated from the control group were +/-10% and +/-5% for extracellular water and total body water, respectively. Thus, despite strong correlations between MFBIA and isotope measurements, the relatively large limits of agreement with accepted techniques suggest that the MFBIA technique requires further refinement before it can be routinely used to determine the nutritional assessment of individual cirrhotic patients.

Dynamic assessment of fat-free mass during catabolism and recovery

Catabolism of fat-free mass affects both the quality of life and survival of patients. Because of variations in fluid status during acute illness, changes in body weight are difficult to evaluate and interpret during treatment. Nutritional assessment should therefore evaluate fat-free and fat mass changes during metabolic stress and catabolism. We have chosen to discuss bioelectrical impedance analysis, including the various bioelectrical impedance analysis techniques (i.e. multi-frequency and bioimpedance spectroscopy), as an easy, non-invasive, portable bedside technique that is operator-independent for evaluating fat-free and fat mass compartments and their changes during treatment. Clinical examples of the determination of fat-free mass in healthy and ill individuals are also presented.

The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa

Total body water (TBW) was measured by deuterium oxide (D2O) dilution and predicted from bioelectrical impedance (Z) in nineteen anorexic and twenty-seven control women. The equation of Kushner et al. (1992) based on the impedance index (ZI = height2/Z) gave biases of 0.9 (SD 2.5) and 0.8 (SD 2.5) litres in controls and patients respectively (NS, ANOVA). The ZI-based equation of Deurenberg et al. (1993) gave biases of 1.5 (SD 2.4) litres (NS) and 3.0 (SD 2.1) litres (P < 0.001) in controls and patients respectively. Despite the fact that weight was the most powerful predictor of TBW on the study sample (n 46, r2 0.90, P < 0.0001, SE of the estimate 1.6 litres, CV 5.7%), the formulas of Segal et al. (1991) and Kushner et al. (1992) based on the association of weight and ZI gave an inaccurate prediction of TBW in both control and anorexic subjects, with a bias ranging from -3.2 (SD 2.4) to 2.9 (SD 2.1) litres (P < or = 0.001). Population-specific formulas based on ZI (n 46) gave a more accurate prediction of TBW by bioelectrical impedance analysis on the study subjects, with biases of -0.1 (SD 1.8) and 0.5 (SD 1.7) litres in controls and patients respectively (NS). However, the individual bias was sometimes high. It is concluded that bioelectrical impedance analysis can be used to predict TBW in anorexic women at a population level, but the predictions are less good than those based on body weight alone.

Assessment of body hydration in subjects with schistosomiasis

Total body water (TBW) was measured by deuterium oxide dilution (D2O) and predicted by bioelectric impedance analysis (BIA) (Deurenberg, Schouten, Andreoli and De Lorenzo 1993) in 21 subjects with Schistosoma mansoni infection and 17 healthy controls of similar age (32.8 +/- 13.7 years, n=38). Patients were selected to have no visible fluid retention and no cardiac or renal abnormalities. Body hydration (TBW per kg of body weight) was significantly higher in patients with schistosomiasis than in controls (62.9 +/- 3.6 vs 57.4 +/- 4.3%, p < 0.0005). A significant correlation was found between albumin levels and TBW% on the pooled sample (n=38; r=0.660, p < 0.0001). This relationship was not influenced by the presence of disease, as determined by ANCOVA. Values of TBW predicted by BIA were highly correlated and not significantly different (p=n.s., ANOVA) from those measured by D2O in both controls and patients (r=0.854, p < 0.001, SEE = 2.3 1, CV=5.9% and r=0.848, p < 0.001, SEE=4.0 1, CV=9.3%, respectively). The bias (TBW by BIA - TBW by D2O) was of 0.9 +/- 3.7 in controls and of -1.3 +/- 4.2 1 in patients. This bias was significantly correlated to TBW% in patients (r=0.575, p < 0.05) but not in controls (p=n.s.). It is concluded that subjects with schistosomiasis show an apparent subclinical increase in body hydration which could affect the prediction of TBW from BIA.