Bioelectrical Impedance Vectors Analysis of Sarcopenic Older Adults Submitted to a Resistance Training Program.

The objective of the present study is to analyze the changes in bioimpedance vector analysis (BIVA) and phase angle (PhA) in sarcopenic older people submitted to a 12-week resistance training (RT) program according to classic and specific analyses. To this end, 20 sarcopenic older adults of both sexes, invited through media, underwent bioimpedance analysis before and after the RT carried out three times a week, for 12 weeks. The mean impedance vectors of the groups established for the confidence ellipses (95% of the confidence ellipse) are compared using Hotelling's T2 test. The distance D from Mahalanobis is also calculated. Classic and Specific BIVA are presented. The resistance values for the classical analyses (R/H) decreased across all groups (whole group, women and men, p < 0.05), with approximate decreases ranging from 9.4% to 10%, while the classic reactance (Xc/H) decreased (p < 0.05) only for the whole group (5.9%) and men (7.7%). For the specific BIVA, trends are verified for the whole sample, with a decrease in resistance (R.sp) and an increase in reactance (Xc.sp). In conclusion, the RT program in sarcopenic individuals promoted a reduction in resistance values in classical analyses, indicating a possible increase in hydration status and, consequently, musculoskeletal mass.

Total and segmental phase angle in a cohort of hospitalised patients with COVID-19: mortality prediction and changes throughout hospitalisation.

Body composition and phase angle (PhA) have been used to predict mortality in multiple diseases. However, little has been studied regarding segmental measurements, which could potentially help assess subtle changes in specific tissue segments. This study aimed to identify the total PhA cut-off point associated with mortality risk and changes in body composition within a week of hospitalisation in non-critical hospitalised patients with COVID-19. A cohort study was conducted where patients underwent to a complete nutritional assessment upon admission and after seven days, and followed up until hospital discharge or death. A receiver operating characteristic curve was constructed to determine the PhA cut-off point, and the Kaplan­Meier estimator was used to determine survival analysis. Segmental and complete body compositions on admission and after 7 d were compared. We included 110 patients (60 men) with a mean age of 50·5 ± 15·0 years and a median BMI of 28·5 (IQR, 25·6­33·5) kg/m2. The median length of hospital stay was 6 (IQR, 4­9) d, and the mortality rate was 13·6 %. The PhA cut-off point obtained was 4°, with significant differences in the survival rate (P < 0·001) and mortality (HR = 5·81, 95 % CI: 1·80, 18·67, P = 0·003). Segmental and whole-body compositions were negatively affected within one week of hospitalisation, with changes in the approach by the graphical method in both sexes. Nutritional status deteriorates within a week of hospitalisation. PhA < 4° is strongly associated with increased mortality in non-critical hospitalised patients with COVID-19.

Cachexia measured by bioelectrical impedance vector analysis and risk of infection in women with rheumatoid arthritis.

Rheumatoid arthritis (RA) patients have a higher frequency of infections than the healthy population. The reason has yet to be explained but involves several factors, of which body composition and rheumatoid cachexia are often overlooked. This study aimed to evaluate whether patients with cachexia, measured by bioelectrical impedance vector analysis, are at an increased risk of developing infections compared with patients without cachexia. A secondary analysis of 186 women with RA enrolled in a randomized trial (ClinicalTrials.gov ID: NCT02900898, September 14, 2016) was completed. Medical records and phone calls were used to record infectious events diagnosed and treated during follow-up. Hazard ratios were calculated using Cox proportional hazard regression analysis, and a predictive model of infection was created. After 36 months of follow-up, 62 patients (26.7% non-cachectic and 44.3% cachectic, p < 0.01) developed at least one infectious event. The most common site of was the urinary tract, followed by the lungs and respiratory tract. The presence of cachexia (HR 1.90, 95% CI 1.15-3.13) and the use of glucocorticoids (HR 1.77, 95% CI 1.01-3.09) were associated with infection in univariate and multivariate models. Body mass index (BMI), smoking, and methotrexate use were not associated with a higher frequency of infections. The presence of cachexia and the use of glucocorticoids were identified as predictors of infections in a cohort of female RA patients. More extensive measurements of body composition should be performed beyond BMI in RA patients to better understand its impact and to prevent additional comorbidities and complications. Key Points • The presence of cachexia measured by bioelectrical impedance vector analysis was associated with infectious events in women with rheumatoid arthritis, whereas body mass index did not show an association. • Glucocorticoids were the only drug associated with a higher frequency of infection. None of the disease-modifying antirheumatic drugs, including methotrexate, showed an association.

Prognostic value of phase angle and bioelectrical impedance vector in critically ill patients: A systematic review and meta-analysis of observational studies.

BACKGROUND AND AIMS: Assessment of the raw parameters derived from bioelectrical impedance analysis (BIA) has gained emphasis in critically ill patients. The phase angle (PhA) reflects the integrity of the cell membrane, and bioelectrical impedance vector analysis (BIVA) is indicative of patients' hydration status. The aim of this study was to investigate whether these parameters are associated with clinical outcomes in the intensive care unit (ICU) setting. METHODS: We conducted a systematic review with meta-analysis. We searched PubMed, Embase, Scopus and Web of Science for all published observational studies without language restrictions up to April 2022. Two reviewers independently performed study selection and data extraction. We judged the risk of bias by the Newcastle-Ottawa Scale and the certainty of evidence by the GRADE approach. Mortality was the primary outcome. Secondary outcomes included ICU length of stay, hospital length of stay, duration of mechanical ventilation, nutritional risk, and malnutrition. A meta-analysis with a random-effect model was performed to combine data on R version 3.6.2. RESULTS: Twenty-seven studies were included in the systematic review (4872 participants). Pooled analysis revealed that patients with low PhA had a higher risk of death (14 studies; RR = 1.82, 95% CI 1.46 to 2.26; I2 = 42%) and spent more days in ICU (6 studies; MD = 1.79, 95% CI 0.33 to 3.24, I2 = 69%) in comparison to patients with normal PhA. The pooled analysis also showed higher PhA values in survivors compared to non-survivor patients (12 studies; MD = 0.75°, 95% CI 0.60° to 0.91°, I2 = 31%). Overhydration defined by BIVA was not a predictor of mortality (4 studies; RR = 1.01, 95% CI 0.70 to 1.46; I2 = 0%). More than 40% of primary studies were classified with a high risk of bias, and the quality of evidence ranged from low to very low. CONCLUSIONS: This meta-analysis revealed, with limited evidence, that low PhA was associated with higher mortality and ICU length of stay, while overhydration identified by BIVA was not a predictor of death in critically ill patients.

Changes in Intra-to-Extra-Cellular Water Ratio and Bioelectrical Parameters from Day-Before to Day-Of Competition in Bodybuilders: A Pilot Study.

The present study analyzed the effects from day-before to day-of bodybuilding competition on intracellular water (ICW), extracellular water (ECW), total body water (TBW), and bioimpedance analysis (BIA) parameters (resistance, R; reactance, Xc; and derived scores) in bodybuilding athletes. We assessed anthropometry and BIA (foot-to-hand; tetrapolar; 50 kHz) in 11 male bodybuilders (29 ± 4 year-old; 81 ± 8 kg; 172 ± 7 cm; 27 ± 2 kg/m2) both on the pre-competition day and on the contest day. Results revealed significant increases in ICW (31.6 ± 2.9 to 33.1 ± 2.8 L), with concomitant decreases in ECW (19.8 ± 1.8 to 17.2 ± 1.4 L) and TBW (51.4 ± 4.6 to 50.3 ± 4.2 L) from the day-before competition to contest day, which resulted in relatively large increases in the ICW/ECW ratio (1.60 ± 0.03 to 1.92 ± 0.01 L). Moreover, significant increases in R (391 ± 34 to 413 ± 33 ohm), Xc (64 ± 7 to 70 ± 6 ohm), and phase angle (9.3 ± 0.6 to 9.6 ± 0.7 degree) were observed between time periods. The phase angle scores reported on show-day of 9.6 and 11.2 appear to be the highest group mean and individual values observed in the literature to date. In conclusion, the strategies carried out on the final day of peak-week bodybuilding preparation lead to changes in BIA parameters and body water, with fluids shifting from the extra- to the intracellular compartment.

The use of bioelectrical impedance vector analysis for a nutritional evaluation of older adults in the community.

INTRODUCTION: The body composition of an older adult person is characterized by an increase in body fat, as well as by a reduction in both muscle mass and total body water. The bioelectrical impedance vector analysis (BIVA) overcomes the limits imposed by bioelectrical impedance, since it only requires the resistance (R) and reactance (Xc) values, standardized by the individual's height, which makes the method more individualized and accurate. The aim of this study was to evaluate the body composition using the BIVA of the community-living older adults, with regard to sex and body mass index (BMI) classification, and compare the results with the reference population. METHODS: Cross-sectional study with the community-living older adults of both sexes. Bioimpedance was carried out and the R and Xc data analyzed, based on height, and plotted on RXc graphs. RESULTS: One hundred and forty-four older adults (n = 33 men; n = 111 women; mean age of 80.2 ± 9.2 years) participated in the study. Low weight (<23 kg/m2) was the most prevalent in BMI classification. The older adult women presented a higher average BMI, body fat percentage and R/Height values, while the older adult men presented a higher average for fat-free mass and the phase angle (p < 0.05). The older adult, regardless of their BMI, located in the right quadrant, indicated cachexia; those with low weight were dehydrated, and those with overweight (BMI ≥ 28 kg/m2) presented hyperhydration. CONCLUSION: The majority of the older adults with normal weight or overweight has impedance vectors indicating loss of muscle mass and water imbalance (dehydration or hyperhydration).

Bioelectrical impedance vector analysis evaluates cellularity and hydration in cirrhotic patients.

BACKGROUND: Malnutrition in cirrhotic patients is correlated with mortality and a better response to liver transplantation. However, recovery of the nutritional status in these patients is a challenge due to the difficulty in establishing a reliable nutritional diagnosis. The bioelectrical impedance vector analysis (BIVA) method appears as a feasible tool in clinical practice to define the physiological state of cirrhotic patients by assessing hydration and body cellularity. AIM: To evaluate body composition in cirrhotic patients using BIVA. METHODS: This retrospective cross-sectional study was carried out by following cirrhotic outpatients at a hospital in Porto Alegre, Brazil. A tetrapolar bioelectrical impedance analysis device was used to evaluate cellularity and hydration and to perform the BIVA. The BIVA graphic was elaborated by software and for statistical analysis a significance level of 5% (P ≤ 0.05) was considered. RESULTS: One hundred and ninety patients, 61.1% males, with a mean age of 56.6 ± 11.0 years, were evaluated. Of these, 56.3% had Child-Turcotte-Pugh (CTP) A score, and the prevalent etiology was hepatitis C virus (47.4%). The patients were classified according to cellularity and hydration by the quadrants and ellipses of the BIVA method, quadrant 1 (47.9%); quadrant 2 (18.9%); quadrant 3 (14.2%); and quadrant 4 (18.9%). Those classified in quadrant 1 and 2 had a higher phase angle compared to those in quadrants 3 and 4 (P < 0.001). Quadrant 2 patients had a lower average age than the other groups. The association with CTP score showed that patients in quadrant 2 had a higher proportion of CTP A, and those in quadrant 4 had a higher proportion of CTP C (P < 0.052). CONCLUSION: The BIVA method allows identification of the cellularity and hydration status of cirrhotic patients, and its association with clinical factors determines the disease severity, age and prognostic index.

Bioelectrical impedance vector analysis and phase angle in boys with Duchenne muscular dystrophy.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a disease characterized by progressive loss of functional muscle mass followed by changes in body composition. OBJECTIVE: This study aimed to describe and evaluate bioimpedance parameters in boys with DMD. DESIGN: This cross-sectional, descriptive study investigated children and adolescents diagnosed with DMD. Age, weight, height, resistance, and reactance data were collected. Phase angle and bioelectrical impedance vector analysis were calculated based on resistance and reactance values. RESULTS: We analyzed 43 boys aged between 2.7 and 19.8 years. Low-phase angle values were observed during the investigation of bioimpedance parameters. Bioelectrical impedance vector analysis showed that approximately 87% of the subjects presented vectors outside the tolerance ellipses, and only one patient presented vectors located within the 50% tolerance ellipse, indicating normally hydrated and a good body cell mass. Compared with the reference population, boys with DMD had lower levels of body cell mass. CONCLUSION: Based on the evidence, compared with the reference population, patients with DMD had lower levels of body cell mass. This evidence points to bioimpedance parameters as useful tools for the nutritional evaluation and clinical management of patients with DMD.

Ethnic differences in fat and muscle mass and their implication for interpretation of bioelectrical impedance vector analysis.

According to the World Health Organization Expert Consultation, current body mass index (BMI) cut-offs should be retained as an international classification. However, there are ethnic differences in BMI-associated health risks that may be caused by differences in body fat or skeletal muscle mass and these may affect the interpretation of phase angle and bioelectrical impedance vector analysis (BIVA). Therefore, the aim of this study was to compare body composition measured by bioelectrical impedance analysis among 1048 German, 1026 Mexican, and 995 Japanese adults encompassing a wide range of ages and BMIs (18-78 years; BMI, 13.9-44.3 kg/m2). Regression analyses between body composition parameters and BMI were used to predict ethnic-specific reference values at the standard BMI cut-offs of 18.5, 25, and 30 kg/m2. German men and women had a higher fat-free mass per fat mass compared with Mexicans. Normal-weight Japanese were similar to Mexicans but approached the German phenotype with increasing BMI. The skeletal muscle index (SMI, kg/m2) was highest in Germans, whereas in BIVA, the Mexican group had the longest vector, and the Japanese group had the lowest phase angle and the highest extracellular/total body water ratio. Ethnic differences in regional partitioning of fat and muscle mass at the trunk and the extremities contribute to differences in BIVA and phase angle. In conclusion, not only the relationship between BMI and adiposity is ethnic specific; in addition, fat distribution, SMI, and muscle mass distribution vary at the same BMI. These results emphasize the need for ethnic-specific normal values in the diagnosis of obesity and sarcopenia.

Body composition evaluated by body mass index and bioelectrical impedance vector analysis in women with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a complex inflammatory disease that modifies body composition. Although body mass index (BMI) is one of the clinical nutrition tools widely used to assess indirectly nutritional status, it is not able to identify these body alterations. Bioelectrical Vector Analysis (BIVA) is an alternative method to assess hydration and body cell mass of patients with wasting conditions. OBJECTIVE: To investigate the differences in nutrition status according to BMI groups (normal, overweight and obesity) and BIVA classification (cachectic and non-cachectic) in women with RA. METHODS: Women with confirmed diagnosis of RA were included from January 2015 to June 2016. Whole-body bioelectrical impedance was measured using a tetrapolar and mono-frequency equipment. Patients were classified according to BMI as: low body weight (n = 6, 2.7%), normal (n = 59, 26.3%), overweight (n = 88, 39.3%) and obese (n = 71, 31.7%), and each group was divided into BIVA groups (cachectic 51.8% and non-cachectic 48.2%). RESULTS: A total of 224 RA patients were included, with mean age 52.7 years and median disease duration of 12 years. Significant differences were found in weight, arm circumference, waist, hip, resistance/height, reactance/height and erythrocyte sedimentation rate among all BMI groups. However, serum albumin levels were significantly different between cachectic and non-cachectic patients independently of BMI. In all BMI categories, cachectic groups had lower reactance and phase angle than non-cachectic subjects. CONCLUSION: RA patients with normal or even high BMI have a significantly lower muscle component. Evaluation of body composition with BIVA in RA patients could be an option for cachexia detection.

Bioelectrical Impedance Vector Analysis in Healthy Term Infants in the First Three Months of Life in Brazil.

OBJECTIVE: Bioelectrical impedance vectorial analysis (BIVA) can be considered a favorable method for evaluation and monitoring of nutritional and hydration status without assumptions regarding body composition or requirement of prediction formulas. The present study aimed to determine bivariate tolerance intervals of the whole-body impedance vector for healthy term infants aged 1 to 3 months. METHODS: This is a descriptive cross-sectional study. Anthropometric and bioelectrical impedance data (800 mA-50 kHz) were obtained. Bivariate vector analysis was conducted with the resistance-reactance (RXc) graph method. BIVA software was used to construct the graphs. RESULTS: A total of 150 appropriate for gestational age infants (48.7% boys) who were exclusively breastfed and were 56.4 (SD = 23.1) days of age were studied. RXc tolerance ellipses (50, 75, and 95%) were constructed for boys and girls, but a general reference graph was defined for all infants considering the overlapping of ellipses between the genders. All graphs differed from those in national and foreign studies. CONCLUSION: New reference tolerance ellipses (95, 75, and 50%) for 1- to 3-month-old infants were constructed, pointing out the need for specific reference values of total body impedance vectors in different regions of Brazil. The RXc tolerance ellipses can be used for clinical practice and provide an easy method to evaluate and monitor body composition and hydration status.

Prevalence of rheumatoid cachexia assessed by bioelectrical impedance vector analysis and its relation with physical function.

Rheumatoid arthritis (RA) patients frequently have changes in their body composition, with a decrease in muscle mass and an increase in fat mass, a syndrome that is termed rheumatoid cachexia (RC). The prevalence of this nutritional alteration is not well known; there is as yet no consensus, seeing as it depends on the methods, techniques, and cutoff points that are used for its diagnosis. The main aim of this study was to identify RC through assessment by bioelectrical impedance vector analysis (BIVA) and its association with metabolic causes, physical function, and the main disease status, among others. The prevalence of RC was identified in those subjects who fell outside the right lower quadrant of the reference curve of RXc graph of BIVA. Clinical, anthropometric, biochemical and physical activity, emotional status, and diet markers were also evaluated. Ninety-four patients were included (92.55% women). The prevalence of RC assessed by BIVA was 21.28%. BIVA-cachexia patients had a lesser value of handgrip strength vs. patients without BIVA-cachexia 10.2 kg (7.2-13.4) vs. 14.7 kg (9.6-19), p = 0.0062. Disability and folic acid with methotrexate consumption are related to BIVA-cachexia ((OR 4.69, 95% CI 1.33, 16.54, p = 0.016) and (OR 0.19, 95%CI 0.058, 0.651, p = 0.008), respectively). BIVA could represent a valuable tool to assess presence of RC. It is important that RA patients have physical therapy to improve their nutritional status.

Usefulness of combining admission brain natriuretic peptide (BNP) plus hospital discharge bioelectrical impedance vector analysis (BIVA) in predicting 90 days cardiovascular mortality in patients with acute heart failure.

Heart failure is a disease characterized by high prevalence and mortality, and frequent rehospitalizations. The aim of this study is to investigate the prognostic power of combining brain natriuretic peptide (BNP) and congestion status detected by bioelectrical impedance vector analysis (BIVA) in acute heart failure patients. This is an observational, prospective, and a multicentre study. BNP assessment was measured upon hospital arrival, while BIVA analysis was obtained at the time of discharge. Cardiovascular deaths were evaluated at 90 days by a follow up phone call. 292 patients were enrolled. Compared to survivors, BNP was higher in the non-survivors group (mean value 838 vs 515 pg/ml, p < 0.001). At discharge, BIVA shows a statistically significant difference in hydration status between survivors and non-survivors [respectively, hydration index (HI) 85 vs 74, p < 0.001; reactance (Xc) 26.7 vs 37, p < 0.001; resistance (R) 445 vs 503, p < 0.01)]. Discharge BIVA shows a prognostic value in predicting cardiovascular death [HI: area under the curve (AUC) 0.715, 95% confidence interval (95% CI) 0.65-0.76; p < 0.004; Xc: AUC 0.712, 95% CI 0.655-0.76, p < 0.007; R: AUC 0.65, 95% CI 0.29-0.706, p < 0.0247]. The combination of BIVA with BNP gives a greater prognostic power for cardiovascular mortality [combined receiving operating characteristic (ROC): AUC 0.74; 95% CI 0.68-0.79; p < 0.001]. In acute heart failure patients, higher BNP levels upon hospital admission, and congestion detected by BIVA at discharge have a significant predictive value for 90 days cardiovascular mortality. The combined use of admission BNP and BIVA discharge seems to be a useful tool for increasing prognostic power in these patients.

Bioelectrical impedance vector analysis as a useful predictor of nutritional status in patients with short bowel syndrome.

BACKGROUND & AIMS: Short bowel syndrome (SBS) represents a serious intestinal absorption disorder. Therefore, patients with SBS may have severe malnutrition and excessive mineral and fluid losses. Once the assessment of nutritional status is important in their follow-up, body composition measurements and especially total body water (TBW) must be repeatedly evaluated for the assessment of changes in hydration and nutritional care. The aim of this study was to investigate if bioelectrical impedance vector analysis (BIVA) is a useful predictor of nutritional and hydration status in SBS patients. METHODS: In this observational study, 22 participants (12 women), 11 with SBS and 11 gender, age and BMI-matched controls, were evaluated using the bioelectrical impedance measurements (BIA) and BIVA to assess nutritional and hydration status. RESULTS: Participants age was 53 ± 8 y (mean ± SD). Body water, fat mass and lean mass as assessed by BIA did not differ between the two groups. However, BIVA showed important differences between the groups regarding hydration and amount of soft tissue (p < 0.0001 for women and p = 0.0015 for men). The results also evidenced that women's vectors were related to cachexia, while men's vectors were divided into lean and cachexia quadrants. The use of BIVA analysis also evidenced hydration disturbance and losses of soft tissue. CONCLUSIONS: BIVA may represent a better predictor of nutritional status for analysis and interpretation of body composition in patients with short bowel syndrome. This trial was registered at ClinicalTrials.gov as NCT02113228.

Nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children.

BACKGROUND: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cell-mediated immune dysfunction, and cognitive impairment. OBJECTIVE: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children. DESIGN: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n=31) and an experimental group (10 mg Zn/day, n=31) for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. RESULTS: Our study showed (1) an increased body mass index for age and an increased phase angle in the experimental group; (2) a positive correlation between nutritional assessment parameters in both groups; (3) increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4) increased consumption of all nutrients, including zinc, in the experimental group; and (5) an increased serum zinc concentration in both groups (p<0.0001). CONCLUSIONS: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Bioelectrical impedance vector analysis for evaluating zinc supplementation in prepubertal and healthy children.

BACKGROUND: The prevalence of abnormal nutritional status has increased in children and adolescents. Nutritional assessment is important for monitoring the health and nutritional status. Bioelectrical impedance vector analysis (BIVA) combines changes in tissue hydration and structure and body composition that can be assessed. OBJECTIVES: The objective of this study was to use BIVA to evaluate nutritional status in 60 prepubertal children, aged between 8 and 9 years, supplemented with zinc, to detect possible changes in body composition. DESIGN: We performed a randomized, controlled, triple-blind study. The children were divided into the control group (CG; sorbitol 10%, n=29) or the experimental group (EG; 10 mg Zn/day, n=31), and the duration of the experiment was 3 months. Anthropometric assessments were performed for all of the children. RESULTS: The body mass index-for-age increased after oral zinc supplementation in the EG (p=0.005). BIVA indicated that the CG demonstrated a tendency for dehydration and decreased soft tissue and the EG demonstrated a tendency for increased soft tissue, primarily the fat-free mass. After analyses of BIVA ellipses, we observed that this method could detect improvements in body composition in healthy children supplemented with zinc. CONCLUSIONS: These results suggest that BIVA could be an auxiliary method for studying a small population undergoing zinc intervention.