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Phase angle (PhA) is a recently proposed marker of nutritional status in many clinical conditions. Its use in patients with obesity presents different critical concerns due to the higher variability of the two measured parameters (resistance, R, and reactance, Xc) that contribute to the determination of PhA. Controversial is the relation between PhA and BMI that might vary with graded levels of obesity due to the variation in fat and free fat mass. Obesity is frequently associated with metabolic, hepatic, cardiovascular and kidney diseases that introduce variations in PhA values, in relation to multimorbidity and severity degree of these diseases. It is reported that the improvement of clinical condition is associated with a positive change in PhA. Also, the treatment of obesity with weight loss might confirm this effect, but with different responses in relation to the type and duration of the intervention applied. In fact, the effect appears not only related to the percentage of weight loss but also the possible loss of free fat mass and the nutritional, metabolic and structural modifications that might follow each therapeutic approach to decrease body weight. We can conclude that the PhA could be used as marker of health status in patients with obesity supporting an appropriate weight loss intervention to monitor efficacy and fat free mass preservation. [ABSTRACT FROM AUTHOR]

Resistance training has been proposed as a valid practice to counteract the aging effect on body mass and its components, which can be easily evaluated though the bioelectrical impedance analysis. This study aimed to achieve a systematic review with meta-analysis on the impact of resistance training on bioelectrical proprieties in older adults. A literature review was done in four electronic databases up to 1 January 2022. The inclusion criteria were: (i) participants aged ≥ 60 years; (ii) resistance training lasted ≥ 8 weeks; (iii) measurement of raw bioelectrical parameters in randomized controlled study designs. The outcomes of the trial had to be bioelectrical phase angle (PhA), resistance (R), and reactance (Xc). The methodological quality was assessed using the Rosendal scale. Overall, seven studies with a total of 344 participants were eligible for the analysis. The quality assessment yielded a score of 71.3%. Bioelectrical PhA (0.52 degree [95%CI 0.32, 0.71], p < 0.001) and Xc (3.58 ohms [95%CI 1.97, 5.19], p < 0.001) increased, whereas R decreased (-28.50 ohms [95%CI -41.39, -15.60], p < 0.001) after the resistance training programs. In this meta-analysis, resistance training promoted increases of PhA, which result from an increase in Xc concomitant with a reduction in R. According to the bioimpedance vector analysis, resistance-trained people experienced a beneficial leftward vector displacement, whilst inactivity induced a rightward vector displacement within the R-Xc graph. In future, more sophisticated and rigorous studies that address specific criteria, methods and targeted designs are required to identify which equipment and protocols allow for an optimization of the resistance training effects. Registration code in PROSPERO: CRD42020168057. [ABSTRACT FROM AUTHOR]

Background and purpose The prevalence of sarcopenia varies depending on environments and populations of older people. What is more, in separate studies different diagnostic criteria are used. The aim of this study was to investigate the prevalence of sarcopenia in an examined sample of older patients and to verify whether bioelectrical impedance analysis (BIVA) may be used as an auxiliary method in diagnosing of sarcopenia among hospitalized older patients. Materials and methods The European Working Group of Sarcopenia in Older People (EWGSOP) algorithm using two different muscle mass criteria was applied and among misclassified subjects we used BIVA parameters to verify the prevalence of sarcopenia. Results The prevalence of sarcopenia ranged between 60.7% and 79.8% according to the two suggested different muscle mass cutpoints. Seventeen subjects mismatched according to used muscle mass cutpoints were further analyzed individually on the basis of their mean BIVA parameters. The location of the confidence ellipse of misclassified women overlapped with the women group diagnosed as “nonsarcopenic”, while sarcopenic group was statistically different. Conclusions BIVA is a valuable tool that may be used as an auxiliary method to verify the prevalence of sarcopenia among older women. Mismatched women were characterized with BIVA parameters similar to that of nonsarcopenic women and clearly different from BIVA parameters of their sarcopenic peers. Due to the small number of nonsarcopenic men in our sample further studies are required to verify if this method may also be an additional assessment tool for men. [ABSTRACT FROM AUTHOR]

Risk prediction in patients admitted with acute decompensated heart failure (ADHF) remains a challenge. Biomarkers may improve risk prediction, which in turn may help to better inform patients regarding short-term and long-term prognosis, therapy and care. Most data on biomarkers have been derived from patient cohorts with chronic heart failure. In ADHF, currently, risk tools largely rely on common clinical and biochemical parameters. However, ADHF is not a single disease. It presents in various manners and different etiologies may underlie ADHF, which are reflected by different biomarkers. In the last decade, many studies have reported the prognostic value of these biomarkers. These studies have attempted to describe a value for statistical modeling, e.g., reclassification indices, in an effort to report incremental value over a clinical model or the 'gold standard'. However, the overall incremental predictive value of biomarkers has been modest compared to already existing clinical models. Natriuretic peptides, e.g., (NTpro-)BNP, are the benchmark, but head-to-head comparisons show that there are novel biomarkers with comparable prognostic value. Multimarker strategies may provide superior risk stratification. Future studies should elucidate cost-effectiveness of single or combined biomarker testing. The purpose of this review was to provide an update on current biomarkers and to identify new promising biomarkers than can be used in prognostication of acute heart failure. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to ascertain the efficacy of bioelectrical impedance vector analysis (BIVA) in assessing body composition in the elderly by comparing findings with the results of dual-energy X-ray absorptiometry (DXA), and to test an analytical variant of the method (specific BIVA). Design: Cross-sectional study. Participants: The sample comprised 207 free-living elderly individuals (75 men and 132 women) aged 65 to 93 years. Measurements: Anthropometric and bioelectrical measurements were taken according to standard criteria. BIVA was applied using the 'classic' procedure and correcting bioelectrical values for body geometry to obtain an estimate of the whole-body impedivity. DXA was used as a reference body composition assessment method. BIVA (classic and specific values) and DXA findings were compared using Student's t and Hotelling's T2 tests, and Pearson's correlation coefficient. Results: In both sexes, BIVA distinguished between individuals with different amounts of fat and fat-free mass (lean mass including bone mineral content), according to DXA, but not between those with different proportions of fat mass (FM%). Specific bioelectrical values detected changes in body composition. Conclusion: BIVA should be used with caution for evaluating body composition in the elderly. Specific bioelectrical values proved effective, showing promise as a methodological variant of BIVA, suitable for identifying age-related changes in body fatness. [ABSTRACT FROM AUTHOR]

Objectives: This paper evaluates the nutritional status in patients with mild-moderate and severe Alzheimer's disease (AD) by bioelectrical impedance vector analysis (BIVA). Design: Cross-sectional study. Setting: Alzheimer Center, SS. Trinità Hospital, Cagliari, and 'Monsignor Angioni' Nursing Home, Quartu Sant'Elena (Cagliari, Italy). Participants: 83 free-living patients with mild-moderate Alzheimer's disease (29 men, 54 women), 9 institutionalized women in the severe stage; 468 age-matched controls (202 men, 266 women). Measurements: Mini Nutritional Assessment (MNA), anthropometric (height, weight, BMI), bioelectrical (R, Xc) and biochemical variables (serum albumin) were assessed. Results: Bioelectrical characteristics were significantly different in the patients with mild-moderate AD with respect to controls, indicating low body cell mass (men, T= 12.8; women, T=34.9; p<0.01). Women with severe AD showed low body cell mass and dehydration with respect to patients with mild-moderate AD (T=17.1; p<0.01). The phase angle, R/H and Z/H were significantly correlated (p<0.05) with MNA (phase: r = 0.31; R/H: r =−0.37; Z/H: r =−0.37) and albumin (phase: r=0.47; R/H: r=−0.36; Z/H: r=−0.36). Conclusion: Alzheimer's disease is characterized by a tendency to malnutrition, present even in the mild-moderate stages, and a tendency to dehydration that appears in the severe stage. The BIVA technique is a promising tool for the screening and monitoring of nutrition and hydration status in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

The objective was to present our clinical experience with bioelectrical impedance vector analysis (BIVA). Forty-six patients with chronic kidney disease (CKD) without oedema, 21 oedematous nephrotic children and 15 in remission from nephrotic syndrome were studied. The age range was 2–14 years. Data were obtained with the vector bioelectric impedance analysis method (Piccoli’s RXc graph with 95% confidence ellipses) and compared with normal paediatric values. The mean vector position differs significantly among the groups of evaluated patients (Hotelling T2 test, p < 0.05). Mean vector position along the 45° direction (major axis of ellipses) indicates a progressive increase in body fluid volume from patients with CKD stage IV to stages II–III to patients in remission from nephrotic syndrome to oedematous subjects. We observed a progressive vector lengthening in children with severe renal disease (separate 95% confidence ellipse). This pattern indicates relative dehydration. BIVA represents a useful clinical tool that is able to detect changes in hydration. [ABSTRACT FROM AUTHOR]