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Background and objective: Overhydration in hemodialysis patients is associated with cardiovascular mortality. Adequate removal of liquids and achievement of dry weight is one of the main goals of therapy. So far there are no clinical or laboratory parameters that are reliable, simple and affordable for its determination. The bioelectrical impedance vector analysis (BIVE) is a tool that allows identifying and monitoring hydration status, so the aim of this study was to use BIVE to adjust the intensity of ultrafiltration and achieve dry weight in hemodialysis patients. Methods: We studied 26 patients on hemodialysis, which were performed monthly measurements of bioelectrical impedance for four months. Corresponding vectors were plotted to know in an individual way the state of hydration, according to which the dry weight was adjusted when necessary. Results: Dry weight adjustment was performed in 13 patients, 7 of which required increase and 6 decrease of dry weight. The displacement of vectors on the ellipses corresponded to the type of intervention made. Dry weight was reached in 84.6% of patients at the end of the study with a significant decrease in mean arterial blood pressure and an increase in phase angle in the group of decrease of dry weight. Conclusions: Bioelectrical impedance vector analysis is an useful tool for adjusting the dry weight in patients undergoing hemodialysis. [ABSTRACT FROM AUTHOR]

Background: the differences in bioelectrical impedance vector analysis (BIVA) results from different analyzers that use different bioelectrical impedance analysis (BIA) measurement technologies are not known. This study aimed to identify the degree of agreement between the BIVA results of four different BIA measurement techniques and to evaluate the degree of agreement between their estimates of fat-free mass (FFM) and fat mass (FM) and those determined by the gold-standard method of dual-energy X-ray absorptiometry (DEXA) in a subgroup of patients without overhydration. Methods: a cross-sectional study was conducted with hemodialysis (HD) patients with end-stage renal disease (ESRD) aged 18 to 65 years. BIA was measured with four different techniques: spectroscopic (BIA-BIS), multifrequency (BIA-MF), single-frequency (BIA-SF), and segmental multifrequency (BIA-MS) techniques. The differences and concordance between the components of the BIA (resistance, reactance, and phase angle) of the four devices were analyzed. Patients with a normal hydration status were identified, and concordance between FM and FFM meas)urements with each impedance device and DEXA was observed only in these patients. Results: thirty patients were included. The concordance between the components of BIA ranged from good to excellent (phase angle: intraclass correlation coefficient (ICC) = 0.82, 95 % confidence interval (CI): 0.77-0.93; resistance: ICC = 0.98, 95 % CI: 0.92-0.99). The overall concordance for BIVA diagnosis between the analyzers was substantial for hydration (k = 0.71, 95 % CI: 0.71-0.72) and for body tissues (k = 0.68, 95 % CI: 0.67-0.68). Bland–Altman plots showed the lowest bias between BIA-BIS and DEXA for both FM and FFM. Conclusions: the agreement among the four devices was good for diagnosis by BIVA. The BIA-BIS analyzer and DEXA had the lowest bias for both FFM and FM, although with higher limits of agreement. The lowest limits of agreement were found with the BIA-MS analyzer. [ABSTRACT FROM AUTHOR]

Background: the evaluation of hydration status and body composition in patients with kidney disease is vital for proper management, since overhydration is associated with cardiovascular complications. Patients with chronic kidney disease (CKD) begin to show perceptible alterations in hydration during the intermediate stages of the disease; however, there is little information regarding the evaluation of blood volume status through bioelectrical impedance vector analysis (BIVA) in this population. Objective: to determine the association between hydration status measured with BIVA and biochemical and clinical parameters and mortality in patients with stage G3a, G3b and G4 CKD. Material and methods: a cross-sectional study was conducted with patients with stage G3a, G3b and G4 CKD who underwent bioelectrical impedance analysis (BIA). The following biochemical and clinical parameters were determined: serum and urinary albumin, hematocrit, serum electrolytes and creatinine, estimated glomerular filtration rate (eGFR, using the CKD-EPI formula), 24-hour urine output and blood pressure. The clinical and biochemical variables were associated with the components of the BIA. According to the resistance/height (R/H) and reactance/height (Xc/H) values, the BIVA results were individually plotted on reference ellipses to identify patients with abnormal hydration states. The patients were classified by group according to hydration status and CKD stage z-scores, and differences in clinical, biochemical and BIA parameters were identified. Mortality was determined by hydration status. Results: a total of 138 subjects, 69 men and 69 women, were studied. An association was found between the BIVA components (R/H, Xc/H and phase angle (PA) and serum albumin (albumin and R/H, r = -0.38, p = 0.001; Xc, r = 0.59, p = 0.000; PA, r = 0.58, p ≤ 0.0010). When the biochemical and clinical parameters were compared by hydration status, significant differences were found in eGFR (p = 0.01), serum calcium (p ≤ 0.001), serum albumin (p ≤ 0.001), hemoglobin (p = 0.04), hematocrit, (p = 0.04) and mean arterial pressure (p = 0.03). The patients were followed for a median of 65.5 months (IQR: 53.0 to 207.0), and 12 (8.6 %) patients with CKD died. The Kaplan-Meier curves showed that patients with overhydration had a significantly higher risk of death than patients with normal hydration. Conclusions: there is an association between the hydration status evaluated by BIVA and clinical and biochemical variables. Patients with overhydration are significantly more likely to die than patients with normal hydration. [ABSTRACT FROM AUTHOR]

Introduction: Background: the evaluation of hydration status and body composition in patients with kidney disease is vital for proper management, since overhydration is associated with cardiovascular complications. Patients with chronic kidney disease (CKD) begin to show perceptible alterations in hydration during the intermediate stages of the disease; however, there is little information regarding the evaluation of blood volume status through bioelectrical impedance vector analysis (BIVA) in this population. Objective: to determine the association between hydration status measured with BIVA and biochemical and clinical parameters and mortality in patients with stage G3a, G3b and G4 CKD. Material and methods: A cross-sectional study was conducted with patients with stage G3a, G3b and G4 CKD who underwent bioelectrical impedance analysis (BIA). The following biochemical and clinical parameters were determined: serum and urinary albumin, hematocrit, serum electrolytes and creatinine, estimated glomerular filtration rate (eGFR, using the CKD-EPI formula), 24-hour urine output and blood pressure. The clinical and biochemical variables were associated with the components of the BIA. According to the resistance/height (R/H) and reactance/height (Xc/H) values, the BIVA results were individually plotted on reference ellipses to identify patients with abnormal hydration states. The patients were classified by group according to hydration status and CKD stage z-scores, and differences in clinical, biochemical and BIA parameters were identified. Mortality was determined by hydration status. Results: a total of 138 subjects, 69 men and 69 women, were studied. An association was found between the BIVA components (R/H, Xc/H and phase angle (PA) and serum albumin (albumin and R/H, r = -0.38, p = 0.001; Xc, r = 0.59, p = 0.000; PA, r = 0.58, p ≤ 0.0010). When the biochemical and clinical parameters were compared by hydration status, significant differences were found in eGFR (p = 0.01), serum calcium (p ≤ 0.001), serum albumin (p ≤ 0.001), hemoglobin (p = 0.04), hematocrit, (p = 0.04) and mean arterial pressure (p = 0.03). The patients were followed for a median of 65.5 months (IQR: 53.0 to 207.0), and 12 (8.6 %) patients with CKD died. The Kaplan-Meier curves showed that patients with overhydration had a significantly higher risk of death than patients with normal hydration. Conclusions: there is an association between the hydration status evaluated by BIVA and clinical and biochemical variables. Patients with overhydration are significantly more likely to die than patients with normal hydration. [ABSTRACT FROM AUTHOR]

Introduction: Background: the differences in bioelectrical impedance vector analysis (BIVA) results from different analyzers that use different bioelectrical impedance analysis (BIA) measurement technologies are not known. This study aimed to identify the degree of agreement between the BIVA results of four different BIA measurement techniques and to evaluate the degree of agreement between their estimates of fat-free mass (FFM) and fat mass (FM) and those determined by the gold-standard method of dual-energy X-ray absorptiometry (DEXA) in a subgroup of patients without overhydration. Methods: a cross-sectional study was conducted with hemodialysis (HD) patients with end-stage renal disease (ESRD) aged 18 to 65 years. BIA was measured with four different techniques: spectroscopic (BIA-BIS), multifrequency (BIA-MF), single-frequency (BIA-SF), and segmental multifrequency (BIA-MS) techniques. The differences and concordance between the components of the BIA (resistance, reactance, and phase angle) of the four devices were analyzed. Patients with a normal hydration status were identified, and concordance between FM and FFM measurements with each impedance device and DEXA was observed only in these patients. Results: thirty patients were included. The concordance between the components of BIA ranged from good to excellent (phase angle: intraclass correlation coefficient (ICC) = 0.82, 95 % confidence interval (CI): 0.77-0.93; resistance: ICC = 0.98, 95 % CI: 0.92-0.99). The overall concordance for BIVA diagnosis between the analyzers was substantial for hydration (k = 0.71, 95 % CI: 0.71-0.72) and for body tissues (k = 0.68, 95 % CI: 0.67-0.68). Bland-Altman plots showed the lowest bias between BIA-BIS and DEXA for both FM and FFM. Conclusions: the agreement among the four devices was good for diagnosis by BIVA. The BIA-BIS analyzer and DEXA had the lowest bias for both FFM and FM, although with higher limits of agreement. The lowest limits of agreement were found with the BIA-MS analyzer. [ABSTRACT FROM AUTHOR]

Background and Objective: Protein energy wasting (PEW) is a common syndrome in patients with chronic kidney disease, related to changes in hydration status, decreased food intake and inflammation. There are several tools for the assessment and diagnosis of such alterations. Bioimpedance vector analysis (BIVA) assess the state of nutrition and hydration, but not the inflammatory component, while the malnutrition inflammation score (MIS) comprises the inflammatory and nutritional factors, but not the state of hydration. The aim of the study was to determine the concordance between MIS and BIVA to assess nutritional status in peritoneal dialysis patients.Methods: We studied 50 patients on peritoneal dialysis which underwent  bioelectrical impedance measurements with an empty peritoneal cavity, also MIS was applied and biochemical parameters were evaluated.Results: The prevalence of malnutrition with VIBE and MIS was 38% and 24% respectively. Statistically significant differences in body mass index (BMI) and phase angle between normally nourished and wasted patients by both methods were found. Body composition, biochemical parameters and impedance vectors were not statistically different between normally nourished and wasted patients. Concordance between methods was 0.314 (p = 0.019).Conclusions: Combined nutritional assessment with MIS and BIVA is necessary for the diagnosis of protein energy wasting syndrome in patients undergoing peritoneal dialysis. [ABSTRACT FROM AUTHOR]

Background and Objective: Overhydration in hemodialysis patients is associated with cardiovascular mortality. Adequate removal of liquids and achievement of dry weight is one of the main goals of therapy. So far there are no clinical or laboratory parameters that are reliable, simple and affordable for its determination. The bioelectrical impedance vector analysis (BIVE) is a tool that allows identifying and monitoring hydration status, so the aim of this study was to use BIVE to adjust the intensity of ultrafiltration and achieve dry weight in hemodialysis patients., Methods: We studied 26 patients on hemodialysis, which were performed monthly measurements of bioelectrical impedance for four months. Corresponding vectors were plotted to know in an individual way the state of hydration, according to which the dry weight was adjusted when necessary., Results: Dry weight adjustment was performed in 13 patients, 7 of which required increase and 6 decrease of dry weight. The displacement of vectors on the ellipses corresponded to the type of intervention made. Dry weight was reached in 84.6% of patients at the end of the study with a significant decrease in mean arterial blood pressure and an increase in phase angle in the group of decrease of dry weight., Conclusions: Bioelectrical impedance vector analysis is an useful tool for adjusting the dry weight in patients undergoing hemodialysis., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

Background and Objective: The bioelectrical impedance vector analysis is useful for the determination of body composition in patients with altered hydration status. The original tolerance ellipses were made in Italian healthy individuals. Due to differences in body composition between populations, the aim of the study was to establish specific tolerance ellipses for the Spanish population and compare them with those ellipses made in the original reference population., Methods: We studied 311 Spanish healthy subjects of both sexes, between 18 and 80 years old, with a BMI between 18 and 31 Kg/m², who underwent measurements of weight, height and bioelectrical impedance. The values of resistance and reactance standardized by height (R/H and Xc/H) derived from the impedance measurement, were used to determine the body composition and construct the specific tolerance ellipses for this population., Results: The characteristics of body composition were different between sex and age groups. We plotted values of R/H and Xc/H of the Spanish population on the Italian tolerance ellipses finding that vectors were placed in left quadrants, indicating different body composition. We therefore built specific tolerance ellipses for Spanish population based on values of R/H and Xc/H. Spanish tolerance ellipses were statistically different from the Italian., Conclusions: The vectors of the Spanish population were different from those of the Italian, hence the importance of having a self-reference pattern., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

Objective: To construct bivariate tolerance ellipses from impedance values normalized for height, which can be used in Mexican population for the assessment of body composition and compare them with others made in different populations., Methods: Body composition was assessed by bioelectrical impedance analysis (BIA) in 439 subjects (204 men and 235 women), 18 to 82 years old, with a BMI between 18-31, using an impedanciometer Quadscan 4000. Resistance, reactance and phase angle were used to calculate bioelectrical impedance vectors and construct bivariate tolerance ellipses., Results: Mean age in men was 47.1 +/- 16 years and 42.4 +/- 13 for women, mean weight (73.4 + 9 vs. 60.1 + 8 kg) and height (1.68 vs. 1.55 m) were significant greater in men than in women (p < 0.002). Women in comparison with men, had greater values of impedance (622.96 +/- 66.16 S2 vs. 523.59 +/- 56.56 D) and resistance (618.96 +/- 66.10 Q 61.97 vs. 521.73 +/- 61.97 2), as well as of resistance and reactance standardized by height (398.24 +/-46.30 S2/m vs. 308.66 +/- 38.44) (44.32 +/- 7.14 i/m vs. 39.75 +/-6.29) respectively, with a significant difference in all of them (p < 0.0001). Similarly, the reactance was greater in females, nevertheless this difference did not reach statistical significance (68.96 +/- 11.17 vs. 67.18 +/- 10.3; p = 0.0861). The phase angle was greater in men than in women, with a statistically significant difference (7.330 +/- 0.88 vs. 6.360 +/- 0.97; p < 0.0001). Bivariate tolerance ellipses (50%, 75% and 95%) derived from Mexican subjects showed a significant upward deviation (p < 0.05) from previously published references from Mexican American and Italian populations. New ellipses of tolerance were therefore constructed for the Mexican population., Conclusions: Bioimpedance vectors in Mexican subjects are significantly different from the existing ones, supporting the need of population specific bivariate tolerance ellipses for the evaluation of body composition.