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

Bioimpedance measurements of fibrotic and acutely injured lung tissues

In injured and diseased tissues, changes in molecular and cellular compositions, as well as tissue architecture, lead to alterations in both physiological and physical characteristics. Notably, the electrical properties of tissues, which can be characterized as bioelectrical impedance (bioimpedance), are closely linked to the health and pathological conditions of the tissues. This highlights the significant role of quantitatively characterizing these electrical properties in improving the accuracy and speed of diagnosis and prognosis. In this study, we investigate how diseases, injuries, and physical conditions can affect the electrical properties of lung tissues, using both rat and human lung tissue samples. Results showed that rat lung and trachea tissues exhibit a frequency-dependent behavior to alternating current (AC) across the frequency range of 0.1-300 kHz. The bioimpedance of the lung tissue increased with the level of aeration of the lung, which was manipulated by altering alveolar pressure (PALV: 1-15 cmH2O; bioimpedance level: 1.2-2.8 kΩ; AC frequency: 2 kHz). This increase is mainly because air is electrically nonconductive. The bioimpedance of rat lungs injured via intratracheal aspiration of hydrochloric acid (HCl; volume: 1 mL; AC frequency: 2 kHz) decreased by at least 82 % compared to that of healthy control lungs due to accumulation of fluids inside the airspace of the injured lungs. Moreover, using decellularized lung tissues, we determined the contributions of cellular components and tissue extracellular matrix (ECM) on the electrical characteristics of the lung tissues. Specifically, we observed a considerable increase in bioimpedance in fibrotic human lung tissues due to excessive ECM deposition (healthy: 70.8 Ω ± 10.2 Ω, fibrotic: 132.1 Ω ± 15.8 Ω, frequency: 2 kHz). Overall, the findings of this study can enhance our understanding of the correlation between electrical properties and pathological lung conditions, thereby improving diagnostic and prognostic capabilities and aiding in the treatment of lung diseases and injuries. STATEMENT OF SIGNIFICANCE: The bioelectrical properties of tissue are closely linked to both its physiological and physical characteristics. This underscores the importance of quantitatively characterizing these properties to improve the accuracy and speed of diagnosis and prognosis. In this study, we investigate how the bioelectrical properties of lung tissues are affected by different physical states and pathological conditions using rat and human lung tissues. As the burden of lung diseases continues to increase, our findings can contribute to improved treatment outcomes by enabling accurate and rapid assessment of lung tissue conditions.

The use of phase angle in patients with digestive and liver diseases

Diseases of the liver and the digestive system can lead to malnutrition through an action of reduced food intake or nutrient use, inflammation and impaired metabolism, which result in substantial changes in body composition. Frequently, malnutrition manifests itself with weight loss and reduced muscle mass. However, weight loss and body mass index lack sensitivity to detect the loss of muscle mass and are not informative in distinguishing body water compartments and in characterizing their distribution. This issue is particularly relevant to these two disease models, which are frequently associated with fluid volume imbalances. Phase angle is a useful indicator for cell membrane integrity, water distribution between the intracellular and extracellular spaces and prediction of body cell mass as it is described by measured components of electrical impedance. Malnutrition, inflammation and oxidative stress impair electric tissue properties leading to lower values of PhA. In patients with inflammatory bowel and liver diseases, PhA was consistently found to be related to nutritional status and body composition, particularly the depletion of lean body mass and sarcopenia. It has been associated with prognosis, disease stage and severity and found to be helpful in monitoring fluid shifts and response to interventions.

Comparison of two malnutrition risk screening tools with nutritional biochemical parameters, BMI and length of stay in Chinese geriatric inpatients: a multicenter, cross-sectional study

OBJECTIVES

The aims of this study were to assess malnutrition risk in Chinese geriatric inpatients using Nutritional Risk Screening 2002 (NRS2002) and Mini-Nutritional Assessment (MNA), and to identify the most appropriate nutritional screening tool for these patients.

DESIGN

Cross-sectional study.

SETTING

Eight medical centres in Hubei Province, China.

PARTICIPANTS

A total of 425 inpatients aged ≥70 years were consecutively recruited between December 2014 and May 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

Nutritional risk was assessed using NRS2002, MNA, anthropometric measurements and biochemical parameters within 24 hours of admission. Comorbidities and length of hospitalisation were recorded. Nutritional parameters, body mass index (BMI) and length of hospital stay (LOS) were employed to compare MNA and NRS2002. Kappa analysis was used to evaluate the consistency of the two tools.

RESULTS

The average age was 81.2±5.9 years (range, 70-98). The prevalence of undernutrition classified by NRS2002 and MNA was 40.9% and 58.6%, respectively. Patients undergoing malnutrition had lower BMI, haemoglobin, albumin and prealbumin (p<0.05), and longer LOS (p<0.05). The NRS2002 showed moderate agreement (κ=0.521, p<0.001) with MNA. Both tools presented significant correlation with age, BMI and laboratory parameters (p<0.001). In addition, a significant association between both tools and LOS was found (p<0.05). In addition, the NRS2002 was not different from MNA in predicting nutritional risk in terms of the area under the receiver operating characteristic curve (p>0.05).

CONCLUSIONS

The results show a relatively high prevalence of malnutrition risk in our sample cohort. We found that NRS2002 and MNA were both suitable in screening malnutrition risk among Chinese geriatric inpatients.

Resistive Part of Impedance as a Possible Indicator of Hepatocellular Carcinoma

BACKGROUND AND AIMS

In this work, the multi-frequency impedance both in normal and liver cancer tissues was studied. This was to investigate the feasibility to detect liver cancer by a low cost, easy to use, and a relatively non-invasive electrical impedance measure technique, and thus potentially improving liver cancer diagnosis.

METHODS

Hepatocellular carcinoma (HCC) was induced in male Wistar rats by the administration of diethylnitrosamine (DEN) during 16 weeks. The electrical impedances at a frequency sweep of 10-100 KHz in the whole body and 10-60 KHz in the liver were taken at the end of the treatment.

RESULTS

The electrical impedance showed that the real component values of the impedance change in HCC. In addition, we found that the imaginary component was not associated with HCC.

CONCLUSION

Our results suggest that the electrical impedance may be used as a diagnostic HCC tool.

The nutritional status of adult female patients with disabilities in Kuwait

Objectives

Adults with disabilities are at a higher risk of malnutrition than are their non-disabled counterparts owing to feeding problems and associated medical conditions. We evaluated the prevalence of malnutrition in a group of institutionalized women and investigated any feeding difficulties and nutrition-related medical problems.

Methods

This study used two versions of the Mini Nutritional Assessment-Short Form (MNA-SF) to screen malnutrition: the MNA-SF1 which uses the body mass index, and the MNA-SF2 which uses the calf circumference. Data were collected from 53 women with intellectual and physical disabilities in a cross-sectional survey of residents of the Kuwait Rehabilitation Centre.

Results

Of all participants, 63.5% were found to be overweight or obese, while 11.5% were underweight. Using the MNA-SF1, 57.7% were found to be at risk of malnourishment while 11.5% were malnourished. More patients were identified to be at risk of malnutrition or to be actually malnourished using the MNA-SF2 (59.6% and 23.1%, respectively). Reported feeding problems included difficulties in maintaining a sitting position, manipulating food on a plate, conveying food to the mouth, and in swallowing. The presence of infections worsened the prognoses of malnourished women regardless of their weight status.

Conclusions

Our findings suggest that MNA-SF2 is a more sensitive tool for identifying malnourishment than MNA-SF1. Obesity can obscure the identification of malnourished patients if clinicians rely solely on the MNA-SF1, which uses the body mass index.

Development of a simple predictive model for decreased skeletal muscle mass in patients with compensated chronic liver disease

AIM

To develop and validate a simple predictive model using easily obtained clinical parameters to predict decreased skeletal muscle mass (DSMM) in chronic liver disease (CLD) patients (n = 652).

METHODS

Study subjects were divided into a training set (n = 326) and a validation set (n = 326). Decreased skeletal muscle mass was diagnosed based on skeletal muscle mass index measured by bioimpedance analysis. Variables significantly associated with DSMM were identified using univariate and multivariate analyses in the training set and used to construct a predictive formula. Receiver operating characteristic (ROC) curve analysis was carried out and the predictive model was validated in the validation set. Subgroup analyses were undertaken based on gender, age, or cirrhosis status of patients.

RESULTS

Body mass index (BMI), age, serum albumin, and branched-chain amino acid to tyrosine ratio (BTR) were determined to be significant predictive factors for DSMM. A composite formula "BALB score" was constructed [-7.740 + (0.539 × BMI) + (-0.112 × age) + (1.358 × albumin) + (-0.264 × BTR)]. The BALB score had the best predictive characteristics among all variables in both population sets (area under the ROC curve, 0.877-0.898). Patients with DSMM were stratified into three BALB score categories (>4, 0-4, and <0). Subgroup analyses also showed that BALB scoring was predictive of DSMM irrespective of gender, age, or cirrhosis status. The BALB score significantly correlated with psoas muscle index on computed tomography (rs  = 0.6083 for men; rs  = 0.6814 for women).

CONCLUSION

The BALB scoring system based on routinely used clinical parameters offers a convenient and non-invasive method for predicting DSMM in compensated CLD patients with high accuracy.

Phase angle is associated with advanced fibrosis in patients chronically infected with hepatitis C virus

AIMS

The objective of this study was to evaluate the association of phase angle (PhA) with advanced liver fibrosis in patients chronically infected with hepatitis C virus (HCV).

MAIN METHODS

One hundred sixty consecutive patients chronically infected with HCV were treated at the Hepatitis C outpatient care setting of our hospital from April 2010 to May 2011 and prospectively evaluated. Bioelectrical impedance analysis measurements were performed during the first hospital visit. Biochemical measurements and liver biopsy data were collected from the patients' medical records and included in the analysis only if they were performed within three months of the inclusion of the patient in the study.

KEY FINDINGS

One hundred sixty consecutive patients were evaluated and 25 patients were excluded. A total of 135 patients with 49.8±11.4years old were studied. Among these patients, 60% were male and the PhA was 6.5±0.8°. Regarding the stage of fibrosis, patients with advanced fibrosis were older and had more insulin resistance and more inflammation compared with patients that had mild fibrosis. Logistic regression analysis revealed that PhA was a predictor of advanced fibrosis even when adjusted for gender, age, HOMA-IR, HDL-cholesterol and AST (OR: 0.227; CI 95%: 0.090-0.569; p: 0.013). The best PhA cut-off points associated with advanced fibrosis for the combined data, for females and for males were 6.43°, 5.94° and 6.72°, respectively.

SIGNIFICANCE

PhA was predictor of advanced liver fibrosis in patients chronically infected with HCV. In the sample evaluated, for each one-degree decrease in PhA, the risk of advanced fibrosis increased more than four-fold.

Malnutrition in cirrhosis increases morbidity and mortality

BACKGROUND AND AIMS

Malnutrition is frequent in patients with cirrhosis and is associated with complications like ascites, hepatic encephalopathy, infections, and death. We determined the prevalence of malnutrition by various methods and its clinical importance in patients with cirrhosis.

METHODS

Consecutive patients of cirrhosis from August 2013 to February 2015 were assessed. Nutritional status was assessed by traditional model (mid-arm circumference, triceps skinfold thickness, serum albumin, creatinine height index, total lymphocyte count), handgrip, and body composition analysis measuring skeletal muscle mass and body fat mass. All patients were followed up for 12 months to assess the outcome.

RESULTS

247 patients (age 42.10 ± 10.14 years, 81% male) were included in the study. Etiology of cirrhosis was alcohol in 53% patients. Prevalence of malnutrition was 59.5% according to traditional model, 66.8% by body composition analysis and 71.4% by handgrip. Nutritional status was poor in alcoholic cirrhotics versus nonalcoholics as assessed by triceps skinfold thickness (9.33 ± 2.9 vs 11.64 ± 3.5 mm; P = 0.001), serum albumin (25.1 ± 4 vs 28.1 ± 4 g/L; P = 0.001), and body fat mass (7.6 ± 3.1 vs 8.7 ± 3.3 kg; P = 0.008). Prevalence of malnutrition was 12/27 (44.5%), 96/131 (73.3%) and 84/89 (94.4%) in Child's class A, B, and C respectively. Complications requiring hospitalization (71.3% vs 38.2%; 0.002) and mortality (41.1% vs 18.2%; P = 0.001) were more in malnourished patients compared to well nourished. Nutritional assessment parameters significantly correlated with the liver disease severity (P < 0.05).

CONCLUSIONS

Prevalence of malnutrition is high in patients with cirrhosis. It is associated with increased complications and mortality.

Liver Cirrhosis: Evaluation, Nutritional Status, and Prognosis

The liver is the major organ for the metabolism of three major nutrients: protein, fat, and carbohydrate. Chronic hepatitis C virus infection is the major cause of chronic liver disease. Liver cirrhosis (LC) results from different mechanisms of liver injury that lead to necroinflammation and fibrosis. LC has been seen to be not a single disease entity but one that can be graded into distinct clinical stages related to clinical outcome. Several noninvasive methods have been developed for assessing liver fibrosis and these methods have been used for predicting prognosis in patients with LC. On the other hand, subjects with LC often have protein-energy malnutrition (PEM) and poor physical activity. These conditions often result in sarcopenia, which is the loss of skeletal muscle volume and increased muscle weakness. Recent studies have demonstrated that PEM and sarcopenia are predictive factors for poorer survival in patients with LC. Based on these backgrounds, several methods for evaluating nutritional status in patients with chronic liver disease have been developed and they have been preferably used in the clinical field practice. In this review, we will summarize the current knowledge in the field of LC from the viewpoints of diagnostic method, nutritional status, and clinical outcomes.

Comparison of two nutrition assessment tools in surgical elderly inpatients in Northern China

BACKGROUND & OBJECTIVE

Nutrition assessment enables early identification of malnourished patients and those at risk of malnutrition. To determine the prevalence of malnutrition, to analyze the correlation between short-form Mini Nutritional Assessment (MNA-SF) and Nutritional Risk Screening 2002 (NRS2002) with classical nutritional markers among elderly hospitalized patients in surgery departments, with a view to improving nutrition advice for these patients.

METHODS

A total of 142 elderly patients admitted for surgery were enrolled in the study. Within 48 hours of admission, MNA-SF and NRS2002 scale, anthropometric measures and biochemical tests were carried out to assess the nutritional status of each patient.

RESULTS

The prevalence of malnutrition classified by MNA-SF, NRS2002, BMI, serum albumin, hemoglobin, total lymphocyte count, handgrip strength, calf circumference and mid-arm circumference were 45%, 38%, 17%, 22%, 24%, 71%, 36%, 12 % and 15 %, respectively. As the nutritional status classified by both MNA-SF and NRS2002 deteriorated, BMI, serum albumin, hemoglobin, handgrip strength, mid-arm circumference and calf circumference of patients with malnutrition were lower (P < 0.05). MNA-SF and NRS2002 had a unanimous correlation with classical nutritional markers (P < 0.05) except total lymphocyte count (P > 0.05). MNA-SF results showed a moderate agreement (P < 0.001) with NRS2002. Malnourished patients were older than well-nourished patients with NRS2002 (P < 0.05). Digestive disease patients tend to suffer from malnutrition, evaluated by MNA-SF (P < 0.05).

CONCLUSIONS

The results show a relatively high prevalence of malnutrition among elderly patients in our general surgery department, especially in patients with digestive disease. NRS2002 and MNA-SF on elderly patients showed great consistency but significant difference in elderly patients with digestive disease. Both MNA-SF and NRS2002 correlated with each other and with BMI, serum albumin, hemoglobin, handgrip strength, calf circumference and mid-arm circumference. MNA-SF may be a more suitable tool for the nutrition assessment of surgical elderly inpatients.

Evaluation of nutritional indicators and body composition in patients with advanced liver disease enrolled for liver transplantation

PURPOSE

Malnutrition is prevalent in patients with advanced liver disease (LD) related to multifactorial causes. Fluid retention can underestimate the nutritional status based on anthropometric measures. We evaluated nutritional indicators and body composition (BC) in patients with liver cirrhosis and correlated them with LD severity.

METHODS

Forty three patients with LD enrolled for liver transplantation were evaluated by Anthropometric measures, subjective evaluation (Global Assessment of Nutritional Status - SGA) and biochemical indicators. Single-frequency electrical bioimpedance (SFE-BIA) was used to evaluate body composition (BC). It measured resistance (R), reactance (Xc) and the phase angle (PA). LD severity was estimated by Child-Pugh and Meld criteria (Model for End-Stage Liver Disease).

RESULTS

Child-Pugh index between patients was 7.11 ± 1.70 and Meld was 12.23 ± 4.22. Arm Circumference, Arm Muscle Circumference and Arm Muscle Area, SGA, hemoglobin, hematocrit and albumin showed better correlation with disease severity. Xc and PA showed correlation both with Meld and Child-Pugh score when BC were evaluated. PA was depleted in 55.8% of the patients.

CONCLUSIONS

Diagnosis of malnutrition varied according to the method. Global assessment of nutritional status showed better correlation with disease severity than with objective methods. Single-frequency electrical bioimpedance for body composition analysis in cirrhotic patients must be cautiously used; however, primary vectors seems to be valid and promising in clinical practice.

Racial differences in the association between adiposity measures and the risk of hepatitis C-related liver disease

BACKGROUND

African Americans have lower reported likelihood of hepatitis C virus-related cirrhosis than whites. It is unknown whether relative differences in the distribution of adipose tissue, lean mass, and other anthropometric measurements may explain these observed interethnic differences in disease risk.

AIM

: To evaluate the association between anthropometric measurements and advanced liver disease in a cross-sectional study of African American and white male veterans.

METHODS

We used the validated FibroSURE-ActiTest to assess hepatic pathology, and direct segmental multichannel bioelectric impedance analysis for anthropometric measurements. Race-stratified logistic regression was employed to evaluate risk of high fibrosis progression rate (FPR) and advanced inflammation (A2 to A3).

RESULTS

Among 330 eligible males (59% African American), there were 43 white and 57 African American males with high FPR, and 70 African American and 59 white with advanced inflammation. Percentage body fat (%BF) was a stronger predictor of high FPR risk than was a high body mass index in African Americans [odds ratio (OR)(adj)=2.08; 95% confidence interval (CI),0.83-5.23 for highest %BF vs. lowest tertile and OR(adj)=1.50; 95% CI,0.60-3.75 for obese vs. normal body mass index, respectively], but not in whites. Highest lean leg mass was associated with a nonsignificant increased risk of both high FPR and advanced inflammation in African Americans (OR(highFPRadj)=1.73; 95% CI, 0.73-4.10; OR(AdvancedinflammationAdj)=1.65; 95% CI, 0.76-3.56) versus a decreased risk of both in whites (OR(highFPRadj)=0.62; 95% CI, 0.21-1.79; OR(AdvancedinflammationAdj)=0.58; 95% CI, 0.22-1.48).

CONCLUSIONS

Interethnic differences in nontraditional anthropometric measurements like %BF suggests their potential role in understanding interethnic differences in hepatitis C virus-related liver disease risk in males.

Bioelectrical impedance analysis in clinical practice: implications for hepatitis C therapy BIA and hepatitis C

Background

Body composition analysis using phase angle (PA), determined by bioelectrical impedance analysis (BIA), reflects tissue electrical properties and has prognostic value in liver cirrhosis. Objective of this prospective study was to investigate clinical use and prognostic value of BIA-derived phase angle and alterations in body composition for hepatitis C infection (HCV) following antiviral therapy.

Methods

37 consecutive patients with HCV infection were enrolled, BIA was performed, and PA was calculated from each pair of measurements. 22 HCV genotype 3 patients treated for 24 weeks and 15 genotype 1 patients treated for 48 weeks, were examined before and after antiviral treatment and compared to 10 untreated HCV patients at 0, 24, and 48 weeks. Basic laboratory data were correlated to body composition alterations.

Results

Significant reduction in body fat (BF: 24.2 ± 6.7 kg vs. 19.9 ± 6.6 kg, genotype1; 15.4 ± 10.9 kg vs. 13.2 ± 12.1 kg, genotype 3) and body cell mass (BCM: 27.3 ± 6.8 kg vs. 24.3 ± 7.2 kg, genotype1; 27.7 ± 8.8 kg vs. 24.6 ± 7.6 kg, genotype 3) was found following treatment. PA in genotype 3 patients was significantly lowered after antiviral treatment compared to initial measurements (5.9 ± 0.7° vs. 5.4 ± 0.8°). Total body water (TBW) was significantly decreased in treated patients with genotype 1 (41.4 ± 7.9 l vs. 40.8 ± 9.5 l). PA reduction was accompanied by flu-like syndromes, whereas TBW decline was more frequently associated with fatigue and cephalgia.

Discussion

BIA offers a sophisticated analysis of body composition including BF, BCM, and TBW for HCV patients following antiviral regimens. PA reduction was associated with increased adverse effects of the antiviral therapy allowing a more dynamic therapy application.