Body water distribution in severe obesity and its assessment from eight-polar bioelectrical impedance analysis

Debulking Lymphatic Liposuction: Are the Therapeutic Effects Limited to the Treated Limb?

BACKGROUND AND OBJECTIVES

Lymphedema treatment has traditionally focused on region-specific interventions. However, recent evidence suggests otherwise. This study aims to evaluate whether the benefits of liposuction for lymphedema are confined to the treated limb or extend to other areas of the body.

METHODS

Patients who underwent liposuction for extremity lymphedema between January and June 2023 at Cleveland Clinic were included in the study. Patients with less than 1-year follow-up or incomplete post-operative tracking studies were excluded. Pre- and post-operative evaluations included patient report, 3D volumetric measurements, and indocyanine green lymphography (ICGL). Liposuction was performed under general anesthesia with circumferential removal of pathological bulk.

RESULTS

Thirty-eight limbs in 36 patients (33 females, 3 males, mean age 58 years) underwent surgery. All reported marked improvements, with some noting the improvements as "life-changing." Improvements in lymphatic functions were observed in all operative limbs (38) and non-operative contralateral limbs (38), with an average volume reduction of 30.0% and 19.5%, respectively. ICGL further confirmed improved lymphatic drainage in all limbs (76).

CONCLUSIONS

Liposuction, traditionally considered a region-specific treatment for lymphedema, exerts therapeutic effects beyond the surgical site, suggesting broader systemic benefits.

Effects of Sodium-Glucose Cotransporter-2 Inhibitors on Body Composition and Fluid Status in Cardiovascular Rehabilitation Patients with Coronary Artery Disease and Heart Failure

Background and Objectives: Sodium glucose cotransporter-2 (SGLT-2) inhibitors have emerged as integral therapeutic tools in the management of patients with cardiovascular-kidney-metabolic (CKM) syndrome. In addition to their well-documented effects on lowering glucose levels and cardiovascular- and reno-protective actions, SGLT-2 inhibitors, through a reduction in body weight (BW), generate changes in the body composition and volume status that have not been clearly studied. Materials and Methods: This retrospective, observational longitudinal cohort, single-center study analyzed and compared body composition and fluid status measured by bioelectrical impedance analysis (BIA) from weeks 0 to 12 after the initiation of the cardiac rehabilitation (CR) program for coronary artery disease and heart failure in 59 patients who started treatment with SGLT-2 inhibitors (SGLT-2iG) and 112 patients without SGLT-2 inhibitors (non-SGLT-2iG). Results: Changes between the baseline and week 12 in the SGLT-2iG and non-SGLT-2iG were -0.3 L (p = 0.003) and -0.03 L (p = 0.82) in extracellular water (ECW) (p = 0.05), -0.39 L (p < 0.001) and -0.14 L (p = 0.33) in intracellular water (ICW) (p = 0.12), -0.69 (p < 0.001) and -0.16 (p = 0.52) in total body water (TBW) (p = 0.08), and -0.01 (p = 0.37) and -0.001 (p = 0.25) in the ECW/TBW ratio, respectively. After 3 months of exercise therapy in the CR program, patients in the SGLT-2iG showed a greater decrease than the non-SGLT-2iG in weight (-1.34 kg, p < 0.001 vs. -0.99, p = 0.02), body mass index (BMI) (-0.45 kg/m2, p < 0.001 vs. -0.38, p = 0.004), arm circumference (-0.57 cm, p = 0.008 vs. -0.12 cm, p = 0.21), waist circumference (-1.5 cm, p = 0.04 vs. -0.11 cm, p = 0.83), systolic blood pressure (SBP) (-8.9 mmHg, p = 0.049 vs. -4.19, p = 0.08), and diastolic blood pressure (DBP) (-5.15, p = 0.03 vs. -2.85, p = 0.01). The bioelectrical impedance analysis (BIA) revealed a significant decrease in body fat mass (BFM) and visceral fat area, without a loss of lean body mass (LBM) or skeletal muscle mass in the SGLT-2iG. Conclusions: SGLT-2 inhibitors exert beneficial effects on body compartments and volume status. Although they induce modest weight loss, this appears to be mainly directed at ECW, BFM, and visceral fat, without a loss of LBM nor skeletal muscle mass, which could contribute to the observed CKM benefits.

Body Composition Changes and Factors Influencing the Total Weight Loss Rate After Laparoscopic Sleeve Gastrectomy

Objectives: While the effectiveness of metabolic/bariatric surgery has been confirmed, understanding the factors associated with weight loss is paramount for providing guidance in postoperative treatment strategies. Here, we aimed to examine the factors associated with long-term maintenance of weight loss after laparoscopic sleeve gastrectomy (LSG). Methods: This prospective observational cohort included patients who underwent LSG at a single academic health center between January 2017 and June 2022. We examined their body composition using InBody 720 or 770 and analyzed the factors associated with the percentage of total weight loss (%TWL) for 24 months. Results: The median body mass index (BMI) was 38.8 (interquartile range [IQR]: 35.6-46.7) preoperatively, 32.7 kg/m2 (IQR: 28.2-38.7) at 12 months postoperatively, and 33.9 kg/m2 (IQR: 29.1-40.1) at 24 months postoperatively. The lowest BMI was observed at 12 months (p < 0.001 vs. preoperative), followed by a significant increase at 24 months (p = 0.003). However, BMI remained significantly lower at 24 months than preoperatively (p < 0.001). The skeletal muscle mass to fat mass ratio (SMM/FM) was 0.59 (IQR: 0.50-0.71) preoperatively, 0.79 (IQR: 0.58-1.26) at 12 months, and 0.70 (IQR: 0.54-1.05) at 24 months, peaking at 12 months (p < 0.001 vs. preoperative) and decreasing significantly by 24 months (p < 0.001). Nevertheless, the SMM/FM ratio at 24 months remained higher than preoperative values (p < 0.001). Median body weight and %TWL were 86.0 kg and 15.6%, respectively, at 24 months after LSG. The SMM/FM ratio at 12 months was positively correlated with %TWL at 24 months after adjusting for age and sex. Conclusions: The effects of LSG persisted for up to 24 months postoperatively. The SMM/FM ratio 12 months after LSG was associated with the rate of weight loss at 24 months.

The water imbalance of skeletal muscle and muscle weakness in patients with heart failure

AIMS

A high extracellular water (ECW) to intracellular water (ICW) ratio of skeletal muscle as assessed by bioelectrical impedance analysis is reportedly associated with loss of muscle strength. However, the validity of this index for heart failure (HF), which is likely associated with changes in the water distribution, is unclear.

METHODS AND RESULTS

This study involved 190 patients with HF. The total ECW and ICW of both upper and lower extremities were measured, and a high ECW/ICW ratio was defined as an ECW/ICW ratio higher than the median (≥0.636 for men, ≥0.652 for women). Low muscle strength was defined as reduced handgrip strength according to the criteria established by the Asian Working Group for Sarcopenia. Patients with a high ECW/ICW ratio had a lower handgrip strength (21.1 ± 8.1 kg vs. 27.6 ± 9.3 kg, P ≤ 0.05) and 6 min walk distance (329 ± 116 m vs. 440 ± 114 m) than those with a low ECW/ICW ratio. An increasing ECW and/or decreasing ICW was associated with a higher ECW/ICW ratio and a lower handgrip strength (P < 0.05). In the multivariate logistic regression analysis, a high ECW/ICW ratio and low skeletal muscle mass were independently associated with low muscle strength (P < 0.05).

CONCLUSIONS

A high ECW/ICW ratio in limb muscles, that is, the water imbalance of increasing ECW and/or decreasing ICW, is useful in assessing muscle quality in patients with HF.

Body composition differences in patients with Metabolic Dysfunction-Associated Steatotic Liver Disease

Background

Although body composition (BC) has been associated with Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), there is little evidence of differences in BC in patients with MASLD regarding body mass index (BMI). The aim of this study was to determine differences in BC in terms of BMI and metabolic comorbidities in patients with MASLD.

Materials and methods

It is a cross-sectional study with patients who attended the check-up unit. Liver steatosis was evaluated by controlled attenuation parameter, and patients were classified into five groups according to BMI, presence of MASLD, and metabolic characteristics: <25 kg/m2 non-MASLD; <25 kg/m2-MASLD; Overweight-MASLD; Metabolically Healthy Obese (MHO)-MASLD; and Metabolically Unhealthy Obese (MUO)-MASLD. BC was assessed by bioelectrical impedance and a Bioimpedance Vectorial Analysis (BIVA) was carried out. Differences in BC were analyzed by a One-Way ANOVA test. Univariate and multivariate analyses were performed for factors associated with abnormal BC.

Results

A total of 316 patients were included. 59% (n = 189) were male, with a mean age of 49 ± 10 years. Fat% significantly higher according to BMI was not different between BMI <25 kg/m2-MASLD and Overweight-MASLD groups. Skeletal muscle mass (SMM) was significantly lower in obesity groups with respect to overweight and normal weight groups (p < 0.05); however, no differences were observed in the post-hoc analysis. Extracellular Water/Intracellular Water ratio was significantly higher in the MHO-MASLD group and MUO-MASLD group compared with the BMI <25 kg/m2 non-MASLD group and with the BMI <25 kg/m2-MASLD group. Abnormal Waist Circumference (WC) and liver steatosis were independent factors associated with abnormal BC.

Conclusion

BC in MASLD patients varies according to BMI increase; changes could be explained by loss of SMM and not necessarily by the presence of metabolic abnormalities. High WC and the presence of steatosis are independent factors associated with altered BC.

Biomarkers in lymphedema assessment: integrating elastography and muti-frequency bioimpedance analysis

Aim: Multi-frequency bioimpedance analysis (MFBIA) is used to measure lymphedema, but it is a biomarker that is sensitive to stiffness. Lymphedema is a condition that can be accompanied by stiffness, but no studies have considered this, so we tried to use non-invasive elastography as a biomarker for stiffness.Methods & results: This retrospective study included 102 patients with lymphedema, divided into two groups according to the elastography strain ratio: stiff group (elastography strain ratio <0.7, n = 48) and non-stiff group (elastography strain ratio >0.7, n = 54). We estimated the volume of the affected arm based the extracellular water (ECW) volume calculated using MFBIA through a simple linear regression method. The adjusted R2 was 0.044 in the stiff group and 0.729 in the non-stiff group. Stepwise multivariate linear regression was used to investigate the significant factors for estimating the affected arm volume for each group. In the non-stiff group, the significantly associated factors were impedance at 50 kHz, weight, and height (adjusted R2 = 0.724; p = 0.003). In the stiff group, significant associations were observed among impedance at 250 kHz, impedance at 1 kHz, weight, and height (adjusted R2 = 0.705, p = 0.041).Conclusion: Considering the characteristics of lymphedema, using MFBIA concurrently with elastography can be useful biomarker for estimating lymphedema.

Body composition assessment in individuals with class II/III obesity: a narrative review

BACKGROUND

Individuals with class II/III obesity have a high percentage of body fat. Assessing body composition in cases of severe obesity can be difficult and controversial both in clinical practice and scientific research. Thus, it is essential to explore the different aspects of evaluating body composition and to discuss the available methods to assess it in this population.

AIMS

To summarise and discuss the methods used to measure body composition in adults with class II/III obesity and their potential in clinical practice and scientific research.

METHODS

This is a narrative review using data from PubMed, Scielo, and Lilacs databases. Original articles on body composition analysis in adults with class II/III obesity i.e., a BMI ≥ 35 kg/m2 were eligible. Body composition assessment methods were analysed and described.

RESULTS

Some imaging methods produced significantly accurate results. Dual-energy X-ray absorptiometry (DXA) significantly produces accurate results and has been used in clinical studies. However, due to its high cost, it is not applicable in clinical practice. Multifrequency bioelectrical impedance analysis (BIA) has good accuracy and is more appropriate for clinical practice than other methods. We have highlighted several aspects of the importance and applicability of performing body composition analysis in individuals with class II/III obesity.

CONCLUSION

DXA has been considered the most adequate method for clinical research. Multifrequency BIA may be a viable alternative to DXA for use in clinical practice. Assessing body composition and its components is important for people with class II/III obesity. It can help improve the effectiveness of interventions and clinical treatments, especially in reducing the risk of losing muscle mass. Muscle loss can cause sarcopenic obesity and other clinical complications, so understanding body composition is crucial. Assessing body composition can also help understand the impact of interventions on bones and avoid clinical complications.

Factors associated with skeletal muscle mass in middle-aged men living with HIV

BACKGROUND

Despite extensive research on muscle loss in people living with HIV (PLWH), the prevalence and contributing factors specifically among middle-aged men remain unclear. This study aimed to determine the prevalence of low muscle mass within this demographic and to identify associated factors.

METHODS

A total of 378 men living with HIV were enrolled in the study. They were classified into low muscle mass group if they displayed a skeletal muscle index (SMI) <7.00 kg/m2 or fell within the lowest quintile of SMI based on the criteria established by the Asian Working Group for Sarcopenia 2019.

RESULTS

Out of the 378 men living with HIV enrolled, 351 had normal muscle mass, while 27 (7.1%) had low muscle mass. Antiretroviral drugs Zidovudine (AZT) (OR = 0.246, P = 0.022) and higher serum albumin levels (OR = 0.899, P = 0.026) were found to be protective factors against low muscle mass according to quintile grouping. Strong positive associations between SMI and body mass index (BMI), nutritional risk index (NRI), oedema index and fat-free mass index (FFMI) (R > 0.5, P < 0.001) were observed. In addition, both BMI (sensitivity = 0.741, specificity = 0.906) and NRI (sensitivity = 0.963, specificity = 0.601) had high sensitivity and specificity in diagnosing low muscle mass, with critical values of 19.85 and 114.177 for BMI and NRI, respectively. The oedema index was the most effective measure of body composition in detecting abnormal fluid retention with high sensitivity (92.6%) and moderate specificity (71.8%) in identifying individuals with low muscle mass. Notably, PLWH with low muscle mass participants had a significantly higher prevalence (92.6%) of a high oedema index compared with those with normal muscle mass (28.2%). This observation indicates that individuals with HIV who experience reduced muscle mass is commonly accompanied with abnormal fluid retention within the body.

CONCLUSIONS

Antiretroviral medication types, specifically Zidovudine, BMI and NRI can be independent risk factors for low muscle mass in men with HIV. These factors, along with BMI, could be used conveniently to predict low muscle mass. Furthermore, the association between the oedema index and muscle mass suggests that observing signs of oedema may indicate a risk of low muscle mass in PLWH.

Causal relationships between obesity-related anthropometric indicators and sepsis risk: a Mendelian-randomization study

Background

Previous studies have reported an association between obesity and risk of sepsis. However, the results have been inconsistent, and no causal inference can be drawn from them. Therefore, we conducted a Mendelian-randomization (MR) study to investigate causal relationships between available obesity-related anthropometric indicators and sepsis risk.

Methods

We performed MR analyses using genome-wide association study (GWAS) summary statistics on 14 anthropometric indicators [namely body mass index (BMI), waist and hip circumferences (WC, HC), basal metabolic rate (BMR), whole-body fat mass (WBFM), trunk fat mass (TFM), leg fat mass (LFM), arm fat mass (AFM), body fat percentage (BFP), whole-body fat-free mass (WBFFM), trunk fat-free mass (TFFM), leg fat-free mass (LFFM), arm fat-free mass (AFFM), and whole-body water mass (WBWM)], sepsis, critical care sepsis, and 28-day death due to sepsis from the UK Biobank and FinnGen cohort. The primary method of MR analysis was inverse variance-weighted average method. Sensitivity analyses, including heterogeneity and horizontal-pleiotropy tests, were conducted to assess the stability of the MR results. Additionally, we applied multiple-variable MR (MVMR) to evaluate the effect of BMI on the relationship between each anthropometric indicator and sepsis risk.

Results

Our MR analysis demonstrated causal relationships between 14 anthropometric indicators and sepsis of different severities. After we adjusted for BMI, MVMR analyses indicated that WC, BMR, LFM, WBFFM, TFFM, AFFM, and WBWM remained significantly associated with the presence of sepsis (all p < 0.05). A sensitivity analysis confirmed the reliability of our MR results, and no significant horizontal pleiotropy was detected.

Conclusion

This MR study revealed that increases in obesity-related anthropometric indicators had causal associations with a higher risk of sepsis, which might provide important insights for the identification of individuals at risk for sepsis in community and hospital settings.

Comparison of Bioelectrical Impedance Analyser (BIA) with Dual-Energy X-ray Absorptiometry (DXA) Scan in Assessing the Body Composition of Adult Individuals with Type 2 Diabetes Mellitus

Introduction

Assessing the body composition is important in adult patients with type 2 diabetes mellitus to prevent and achieve optimum control during treatment. Bioelectrical impedance analysis (BIA), being a more affordable method of assessing the body composition, should therefore be compared with the gold standard dual-energy X-ray absorptiometry (DXA) to look for a correlation between the two and the potential of BIA to be used widely in this population. A cross-sectional observational study was conducted on 60 patients attending the endocrinology outpatient department (OPD) of a tertiary care centre in Kolkata, India.

Methods

Body composition was measured by both BIA and DXA. Intra-class correlation (ICC) values were calculated between the two methods for fat mass and fat-free mass for three body mass index (BMI) groups and overall.

Results

DXA and BIA correlated well for both fat mass and fat-free mass in the entire study population and in the non-overweight non-obese group (BMI <23) and the obese group (BMI ≥25). However, the overweight group (23 ≥BMI <25) did not correlate well with the above-mentioned parameters.

Conclusion

We suggest interchangeable use of the two methods in the non-overweight non-obese (BM I <23) and obese (BMI ≥25) BMI groups of adult subjects with type 2 diabetes mellitus. However, the low correlation for all parameters in the overweight group points towards exercising caution when taking such measurements by BIA and planning a further study with a larger cohort of such individuals to better evaluate the said correlation.

Comparing Device-Generated and Calculated Bioimpedance Variables in Community-Dwelling Older Adults

Despite BIA emerging as a clinical tool for assessing older adults, it remains unclear how to calculate whole-body impedance (Z), reactance (Xc), resistance (R), and phase angle (PhA) from segmental values using modern BIA devices that place electrodes on both sides of the body. This investigation aimed to compare both the whole-body and segmental device-generated phase angle (PhADG) with the phase angle calculated using summed Z, Xc, and R from the left, right, and combined sides of the body (PhACalc) and to compare bioelectric variables between sides of the body. A sample of 103 community-dwelling older adults was assessed using a 50 kHz direct segmental multifrequency BIA device. Whole-body PhACalc values were assessed for agreement with PhADG using 2.5th and 97.5th quantile nonparametric limits of agreement and Spearman's rho. Bioelectrical values between sides of the body were compared using Wilcoxon rank and Spearman's rho. A smaller mean difference was observed between PhADG and right PhACalc (-0.004°, p = 0.26) than between PhACalc on the left (0.107°, p = 0.01) and on the combined sides (0.107°, p < 0.001). The sum of Z, R, and PhACalc was significantly different (p < 0.01) between the left (559.66 ± 99.55 Ω, 556.80 ± 99.52 Ω, 5.51 ± 1.5°, respectively) and the right sides (554.60 ± 94.52 Ω, 552.02 ± 94.23 Ω, 5.41 ± 0.8°, respectively). Bilateral BIA values do not appear to be interchangeable when determining whole-body measurements. Present data suggest that using right-sided segmental values would be the most appropriate choice for calculating whole-body bioelectrical variables.

Rationale, Design, and Interim Observations of the Steady Movement With Innovating Leadership for Heart Failure (SMILE HF) Registry: A Multicenter Prospective Cohort Registry for Patients With Acute Heart Failure

BACKGROUND AND OBJECTIVES

Heart failure (HF) is a leading cause of hospitalization and death worldwide. The Steady Movement with Innovating Leadership for Heart Failure (SMILE HF) aims to evaluate the clinical characteristics, management, hospital course, and long-term outcomes of patients hospitalized for acute HF in South Korea.

METHODS

This prospective, observational multicenter cohort study was conducted on consecutive patients hospitalized for acute HF in nine university hospitals since September 2019. Enrolment of 2000 patients should be completed in 2024, and follow-up is planned through 2025.

RESULTS

Interim analysis of 1,052 consecutive patients was performed to understand the baseline characteristics. The mean age was 69±15 years; 57.6% were male. The mean left ventricular ejection fraction was 39±15%. The prevalences of HF with reduced ejection fraction, HF with mildly reduced ejection fraction, and HF with preserved ejection fraction were 50.9%, 15.3%, and 29.2%. Ischemic cardiomyopathy (CMP) was the most common etiology (32%), followed by tachycardia-induced CMP (12.8%) and idiopathic dilated CMP (9.5%). The prescription rate of angiotensin-converting enzyme inhibitor/angiotensin receptor blockers/angiotensin receptor/neprilysin inhibitor, beta-blockers, spironolactone, and sodium-glucose cotransporter-2 inhibitors at discharge were 76.8%, 66.5%, 50.0%, and 17.5%, respectively. The post-discharge 90-day mortality and readmission rates due to HF aggravation were 2.0% and 6.4%, respectively. Our analysis reveals the current state of acute HF in South Korea.

CONCLUSIONS

Our interim analysis provides valuable insights into the clinical characteristics, management, and early outcomes of acute HF patients in South Korea, highlighting the current state and treatment patterns in this population.

The extracellular-to-total body water ratio reflects improvement in the activities of daily living in patients who experienced acute stroke

OBJECTIVES

To determine the relationship between bioelectrical impedance analysis (BIA) parameters, including the extracellular water-to-total body water ratio (ECW/TBW), and the activities of daily living (ADL) improvement, in patients who experienced acute stroke.

MATERIALS AND METHODS

This retrospective cohort study included 307 patients (mean age, 72 years; 39 % female) who experienced acute stroke and were admitted to the stroke unit of the Nippon Medical School Hospital (Bunkyo-ku, Tokyo, Japan) between April 2021 and March 2022. The Functional Independence Measure (FIM) was assessed at initial rehabilitation and discharge, and FIM effectiveness was calculated as ADL improvement in the participating acute care hospitals. BIA markers included the skeletal muscle mass index (SMI), phase angle (PhA), and ECW/TBW. Multiple linear regression models were used to estimate the relationship between the FIM effectiveness and each BIA marker.

RESULTS

The mean (±SD) FIM effectiveness was 0.45 ± 0.36. The proportions of low SMI (male, <7.0 kg/m2; female, <5.7 kg/m2) and low PhA (male <5.36 degrees, female <3.85 degrees), were 48.9 % and 43.3 %, respectively. In addition, the proportions of of low (<0.36), normal (0.36-0.40), and high (>0.4) ECW/TBW ratios were 1.3 %, 78.5 %, and 20.2 %, respectively. After adjustments for demographic and clinical variables, low PhA, low ECW/TBW, and high ECW/TBW were all significantly associated with FIM effectiveness (P < 0.05), with β coefficients of -0.126, -0.089, and -0.117, respectively.

CONCLUSIONS

Low and High ECW/TBW and low PhA levels were negatively correlated with improvements in ADL. The ECW/TBW ratio may be an additional indicator of rehabilitation trainability in patients who experience acute stroke.

Association between fat-free mass and survival in critically ill patients with COVID-19: A prospective cohort study

BACKGROUND

Most critically ill patients with COVID-19 experience malnutrition and weight loss associated with negative clinical outcomes. Our primary aim was to assess body composition during acute and late phase of illness in these patients in relation to clinical outcome and secondary to tailored nutrition support.

METHODS

This prospective cohort study included adult critically ill patients with COVID-19. Body composition (fat-free mass [FFM] [exposure of interest], fat mass [FM], skeletal muscle mass [SMM], and phase angle [PA]) was determined with multifrequency bioelectrical impedance analyses in the acute and late phase. Nutrition support data were collected simultaneously. Clinical outcome was defined as intensive care unit (ICU) survival (primary outcome) and 30-90 days thereafter, duration of mechanical ventilation, and length of ICU stay and length of hospital stay (LOS). Nonparametric tests and regression analyses were performed.

RESULTS

We included 70 patients (73% male, median age 60 years). Upon admission, median BMI was 30 kg/m2 , 54% had obesity (BMI > 30 kg/m2 ). Median weight change during ICU stay was -3 kg: +3 kg FM and -6 kg FFM (-4 kg SMM). Body composition changed significantly (P < 0.001). Regarding clinical outcome, only low PA was associated with prolonged LOS (odds ratio = 0.83, 95% CI = 0.72-0.96; P = 0.015). Patients with optimal protein intake (>80%) during acute phase maintained significantly more FFM (2.7 kg, P = 0.047) in the late phase compared with patients who received <80%.

CONCLUSION

FFM decreased significantly during acute and late phase of illness, but we observed no association with ICU survival. Only low PA was associated with prolonged LOS. FFM wasting likely occurred because of disease severity and immobility.

Changes in intracellular water volume after leg lymphedema onset and lymphaticovenular anastomosis as its surgical intervention

OBJECTIVE

To clarify the changes in the intracellular water (ICW) volume in lymphedema-affected legs after lymphedema onset and its surgical intervention (ie, lymphaticovenular anastomosis [LVA]), we investigated the changes in body water composition using bioelectrical impedance analysis.

METHODS

This retrospective case series included 41 women with unilateral secondary leg lymphedema. The volume changes in the ICW and extracellular water (ECW) of the affected leg were measured using an InBody S10 (InBody Co, Ltd) multifrequency bioelectrical impedance analyzer, at both lymphedema onset and 1 year after LVA.

RESULTS

The volume increase with leg lymphedema onset was comparable between the ECW and ICW (0.59 L vs 0.56 L; 95% confidence interval [CI], -0.02 to 0.06; P = .27), and the increase rate was higher for ECW (35.3% vs 22.1%; 95% CI, 9.3%-17.2%; P < .001). The volume reduction at 1 year after LVA was comparable between ECW and ICW (0.23 L vs 0.27 L; 95% CI, -0.08 to 0.02; P = .20), and the reduction rate was higher for ECW (8.7% vs 7.0%, 95% CI, 0.04%-3.2%; P = .044). The volume difference between ICW and ECW remained constant throughout the six measurements before and after LVA (F[3.01, 120.20] = 1.85; P < .14).

CONCLUSIONS

Leg LVA reduced ICW in the lymphedematous leg. The onset of leg lymphedema increased ECW and ICW in the affected limb, and LVA decreased both ECW and ICW. The volume change in the affected leg was comparable between ECW and ICW at both lymphedema onset and after LVA. However, the rate of change was higher for ECW. The volume difference between ICW and ECW remained constant. Using bioelectrical impedance analysis, alterations in ICW volume were detected in the legs affected by lymphedema, both after the onset of lymphedema and after LVA intervention.

Phase angle and extracellular water-to-total body water ratio estimated by bioelectrical impedance analysis are associated with levels of hemoglobin and hematocrit in patients with diabetes

Background

Anemia is one of the common complications of diabetes and is associated with mortality. Phase angle (PhA), ratio of extracellular water to total body water (ECW/TBW) and skeletal muscle mass index (SMI) estimated by bioelectrical impedance analysis (BIA) have been used as prognostic indicators for various chronic diseases and frailty. We aimed to clarify the clinical significance of PhA, ECW/TBW and SMI for anemia in patients with diabetes.

Materials and methods

The values of PhA, ECW/TBW and SMI were estimated by a portable BIA device and blood samples were collected in 371 Japanese patients with diabetes. The relationships of PhA, ECW/TBW and SMI with hemoglobin (Hgb) and hematocrit (Hct) were statistically evaluated.

Results

In simple linear regression analysis, PhA and SMI were positively correlated with Hgb and Hct levels in total subjects, male subjects and female subjects. In contrast, ECW/TBW was negatively correlated with Hgb and Hct levels regardless of sex. Multivariate regression analysis showed that both PhA and ECW/TBW but not SMI independently contributed to Hgb and Hct levels after adjustment of clinical confounding factors in both males and females.

Conclusions

PhA and ECW/TBW but not SMI were associated with levels of Hgb and Hct in patients with diabetes. Therefore, aberrant values of PhA and ECW/TBW suggest a risk of anemia in diabetic patients.

Nutritional status of patients with COVID-19 one year post-ICU stay: a prospective observational study

Objective

Patients discharged from the Intensive Care Unit (ICU) often suffer from physical complaints and poor nutritional intake, which negatively affect nutritional status (NS). Our aim was to describe NS of patients with COVID-19 one year post-ICU stay.

Research Methods & Procedures

Observational study of adult patients with COVID-19 one year post-ICU. NS assessment (nutrient balance, body composition and physical status) was performed. Nutritional intake and nutrition-related complaints were examined. Nutritional requirements were determined with indirect calorimetry and body composition with bio-electrical impedance. Fat-free mass index (FFMI) and fat mass index (FMI) were calculated. Physical status was determined with handgrip strength (HGS), 6-minute walk test, and 1-minute sit to stand test (1MSTST). Descriptive statistics and paired sample t-tests were used for analysis.

Results

We included 48 patients (73% male; median age 60 years [IQR 52;65]). Median weight loss during ICU stay was 13%. One year post-ICU 12% weight was regained. Median BMI was 26 kg/m² and 23% was obese (BMI>30 kg/m² and high FMI). Of the patients, 50% had high FMI and 19% had low FFMI. Median reported nutritional intake was 90% of measured resting energy expenditure. Nutrition-related complaints were seen in 16%. Percentages of normal values reached in physical tests were 92% of HGS, 95% of 6 minute walking distance and 79% of 1MSTST.

Conclusion(s)

Despite almost fully regained weight and good physical recovery in adult patients one year post-ICU stay, NS remained impaired due to elevated FMI, even though reported nutritional intake was below the estimated requirements.

Genetic Predisposition to a Higher Whole Body Water Mass May Increase the Risk of Atrial Fibrillation: A Mendelian Randomization Study

BACKGROUND

Observational studies have found an association between increased whole body water mass (BWM) and atrial fibrillation (AF). However, the causality has yet to be confirmed. To provide feasible protective measures on disease development, we performed Mendelian randomization (MR) design to estimate the potential causal relationship between increased BWM and AF.

METHODS

We implemented a two-sample MR study to assess whether increased BWM causally influences AF incidence. For exposure, 61 well-powered genetic instruments extracted from UK Biobank (N = 331,315) were used as the proxies of BWM. Summary genetic data of AF were obtained from FinnGen (Ncase = 22,068; Ncontrol = 116,926). Inverse-variance weighted (IVW), MR-Egger and weighted median methods were selected to infer causality, complemented with a series of sensitivity analyses. MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO) and Radial MR were employed to identify outliers. Furthermore, risk factor analyses were performed to investigate the potential mechanisms between increased BWM and AF.

RESULTS

Genetic predisposition to increased BWM was demonstrated to be significantly associated with AF in the IVW model (OR = 2.23; 95% CI = 1.47-3.09; p = 1.60 × 10^-7), and the result was consistent in other MR approaches. There was no heterogeneity or pleiotropy detected in sensitivity analysis. MR-PRESSO identified no outliers with potential pleiotropy after excluding outliers by Radial MR. Furthermore, our risk factor analyses supported a positive causal effect of genetic predicted increased BWM on edematous diseases.

CONCLUSIONS

MR estimates showed that a higher BWM could increase the risk of AF. Pathological edema is an important intermediate link mediating this causal relationship.

Causal Association between Whole-Body Water Mass and Sleep Apnea: A Mendelian Randomization Study

Rationale: Growing evidence has suggested that body water content plays a critical role in sleep apnea. However, the causal relationship has not been established. Objectives: This study aimed to investigate whether increased whole-body water mass is causally associated with a higher risk of sleep apnea using two-sample Mendelian randomization (MR) analysis. Methods: Body water mass (BWM)-associated genetic instruments were extracted from a genome-wide association study conducted by Neale Lab, which incorporates 331,315 individuals of European ancestry. Genetic variants for sleep apnea were derived from the FinnGen dataset. MR analysis was performed using inverse variance-weighted and weight median methods, respectively. MR-Egger regression and MR-Pleiotropy Residual Sum and Outlier tests were applied to evaluate the directional pleiotropy. In addition, we performed a multivariable MR analysis that includes body mass index, snoring, and waist-to-hip ratio as covariate exposures to address their confounding effects. To elucidate mechanisms of the association between BWM and sleep apnea, we further conducted MR analysis on common edematous diseases. Results: MR estimates showed that per standard deviation increase in BWM led to an increase in the risk of sleep apnea by 49% (odds ratio [OR], 1.490; 95% confidence interval [CI], 1.308-1.696; P = 1.75 × 10^-9). The result after MR-Pleiotropy Residual Sum and Outlier correction further supports their causal association (OR, 1.414; 95% CI, 1.253-1.595; P = 1.76 × 10^-8). In addition, the multivariable MR analysis indicates a significant causal association between a higher BWM and increased risk of sleep apnea (OR, 1.204; 95% CI, 1.031-1.377; P = 0.036). Genetic predisposition to a higher BWM was also causally related to increased risk of edematous diseases. Conclusions: Our results suggested that increased BWM is a potential risk factor for sleep apnea. Pathologic edema is a possible intermediate factor mediating this causal association.

Validation of a multi-frequency bioelectrical impedance analysis device for the assessment of body composition in older adults with type 2 diabetes

Background

Aging and type 2 diabetes (T2DM) are associated with an increased risk of sarcopenia. Diagnosis of sarcopenia is commonly done using dual-energy X-ray absorptiometry (DXA) in specialized settings. Another available method for assessing body composition is direct segmental multi-frequency bioelectrical impedance analysis (DSMF-BIA). Here, we examine the accuracy of a DSMF-BIA (InBody-770) for assessing body composition in older adults with T2DM when compared to DXA.

Methods

Eighty-four obese/overweight older adults (49 women, 71 ± 5 years) with T2DM who were recruited for the CEV-65 study and had both DSMF-BIA and DXA assessments at baseline were included. The analysis included Bland–Altman plots and intra class correlation coefficients. Sub-analyses were performed according to gender and following 10 weeks of interventions (diet, circuit training, and Empagliflozin).

Results

The leg lean mass results according to DSMF-BIA and DXA were 14.76 ± 3.62 kg and 15.19 ± 3.52 kg, respectively, with no difference between devices according to Bland–Altman analyses (p = 0.353). Assessment of appendicular skeletal mass index did not differ between DSMF-BIA and DXA (7.43 vs. 7.47 kg/m²; p = 0.84; ICC = 0.965, p < 0.0001; mean difference −0.068, p = 0.595). Gender and treatment interventions did not modify the accuracy of the DSMF-BIA when compared to DXA.

Conclusions

In older adults with T2DM the degree of agreement between DSMF-BIA and DXA, was high, supporting the use of DSMF-BIA to measure muscle mass.

Pharmacokinetic Evaluation of Intravenous Vitamin C: A Classic Pharmacokinetic Study

PURPOSE

Intravenous vitamin C (IVC) is used in a variety of disorders with limited supporting pharmacokinetic data. Herein we report a pharmacokinetic study in healthy volunteers and cancer participants with IVC doses in the range of 1-100 g.

METHODS

A pharmacokinetic study was conducted in 21 healthy volunteers and 12 oncology participants. Healthy participants received IVC infusions of 1-100 g; oncology participants received IVC infusions of 25-100 g. Serial blood and complete urine samples were collected pre-infusion and for 24 h post-infusion. Pharmacokinetic parameters were computed using noncompartmental methods. Adverse events were monitored during the study.

RESULTS

In both cohorts, IVC exhibited first-order kinetics at doses up to 75 g. At 100 g, maximum concentration (C_max) plateaued in both groups, whereas area under the concentration-time curve (AUC) only plateaued in the healthy group. IVC was primarily excreted through urine. No saturation of clearance was observed; however, the mean 24-h total IVC excretion in urine for all doses was lower in oncology participants (89% of dose) than in healthy participants at 100 g (99%). No significant adverse events were observed; thus, maximum tolerated dose (MTD) was not reached.

CONCLUSION

IVC followed first-order pharmacokinetics up to 75 g and at up to 100 g had complete renal clearance in 24 h. IVC up to 100 g elicited no adverse effects or significant physiological/biochemical changes and appears to be safe. These data can be used to rectify existing misinformation and to guide future clinical trials.

REGISTRATION

ClinicalTrials.gov identifier number NCT01833351.

Estimation of fluid status using three multifrequency bioimpedance methods in hemodialysis patients

INTRODUCTION

Segmental eight-point bioimpedance has been increasingly used in practice. However, whether changes in bioimpedance analysis components before and after hemodialysis (HD) using this technique in a standing position is comparable to traditional whole-body wrist-to-ankle method is still unclear. We aimed to investigate the differences between two eight-point devices (InBody 770 and Seca mBCA 514) and one wrist-to-ankle (Hydra 4200) in HD patients and healthy subjects in a standing position.

METHODS

Thirteen HD patients were studied pre- and post-HD, and 12 healthy subjects once. Four measurements were performed in the following order: InBody; Seca; Hydra; and InBody again. Electrical equivalent models by each bioimpedance method and the fluid volume estimates by each device were also compared.

FINDINGS

Overall, total body water (TBW) was not different between the three devices, but InBody showed lower extracellular water (ECW) and higher intracellular water (ICW) compared to the other two devices. When intradialytic weight loss was used as a surrogate for changes in ECW (∆ECW) and changes in TBW (∆TBW), ∆ECW was underestimated by Hydra (-0.79 ± 0.89 L, p < 0.01), InBody (-1.44 ± 0.65 L, p < 0.0001), and Seca (-0.32 ± 1.34, n.s.). ∆TBW was underestimated by Hydra (-1.14 ± 2.81 L, n.s.) and InBody (-0.52 ± 0.85 L, p < 0.05) but overestimated by Seca (+0.93 ± 3.55 L, n.s.).

DISCUSSION

Although segmental eight-point bioimpedance techniques provided comparable TBW measurements not affected by standing over a period of 10-15 min, the ECW/TBW ratio appeared to be significantly lower in InBody compared with Seca and Hydra. Results from our study showed lack of agreement between different bioimpedance devices; direct comparison of ECW, ICW, and ECW/TBW between different devices should be avoided and clinicians should use the same device to track the fluid status in their HD population in a longitudinal direction.

Repository Describing the Anatomical, Physiological, and Biological Changes in an Obese Population to Inform Physiologically Based Pharmacokinetic Models

Background

Obesity is associated with physiological changes that can affect drug pharmacokinetics. Obese individuals are underrepresented in clinical trials, leading to a lack of evidence-based dosing recommendations for many drugs. Physiologically based pharmacokinetic (PBPK) modelling can overcome this limitation but necessitates a detailed description of the population characteristics under investigation.

Objective

The purpose of this study was to develop and verify a repository of the current anatomical, physiological, and biological data of obese individuals, including population variability, to inform a PBPK framework.

Methods

A systematic literature search was performed to collate anatomical, physiological, and biological parameters for obese individuals. Multiple regression analyses were used to derive mathematical equations describing the continuous effect of body mass index (BMI) within the range 18.5–60 kg/m² on system parameters.

Results

In total, 209 studies were included in the database. The literature reported mostly BMI-related changes in organ weight, whereas data on blood flow and biological parameters (i.e. enzyme abundance) were sparse, and hence physiologically plausible assumptions were made when needed. The developed obese population was implemented in Matlab^® and the predicted system parameters obtained from 1000 virtual individuals were in agreement with observed data from an independent validation obese population. Our analysis indicates that a threefold increase in BMI, from 20 to 60 kg/m², leads to an increase in cardiac output (50%), liver weight (100%), kidney weight (60%), both the kidney and liver absolute blood flows (50%), and in total adipose blood flow (160%).

Conclusion

The developed repository provides an updated description of a population with a BMI from 18.5 to 60 kg/m² using continuous physiological changes and their variability for each system parameter. It is a tool that can be implemented in PBPK models to simulate drug pharmacokinetics in obese individuals.

Characteristics and Patient Reported Outcome Measures in Lipedema Patients-Establishing a Baseline for Treatment Evaluation in a High-Volume Center

Lipedema patients suffer not only from visual stigma but also reduction in their quality of life through pain and performance loss in daily life. In clinical practice, it is still difficult to reliably diagnose the disease. This study aims to provide further insights into the characteristics of lipedema patients of all stages and provide a baseline prior to surgery for a surgical treatment evaluation by means of patient-reported outcome measures. Methods: Patients completed a lipedema-specific questionnaire containing 50 items, the World Health Organization Quality of Life BREF (WHOQOL-BREF) and the Patient Health Questionnaire 9 (PHQ-9). The data were analyzed using SPSS statistics 27. Patients who had already received liposuction were excluded. Results: Five hundred and eleven patients were included, of whom 337 completed the PHQ9 and 333 completed the WHOQOL-BREF questionnaires. The general characteristics of lipedema patients, especially the daily symptoms, are described. Previous observations, such as the frequent occurrence of hypothyroidism and the low rate of type 2 diabetes, were confirmed. Over 49% suffer from severe impairments in their jobs, whereby the disease shows a familial accumulation. The results of the WHOQOL-BREF and the PHQ-9 suggest a high level of mental stress. Discussion: As surgical intervention in lipedema patients is gaining traction, its effects should be well-documented. Therefore, a comprehensive baseline needs to be established prior to surgical treatment. The psychological components are just as important as the inclusion of daily impairments.

Consistency of the estimated target weights and ECW/TBW using BIA after hemodialysis in patients between standing and lying-down positions

Background

As hemodialysis is administered with the patient lying down, the distribution of body fluid is stable in the lying position, which is why this position is recommended for bioimpedance analysis (BIA). Although the InBody S10 is widely used for hemodialysis patients in the lying position, clinicians must make the measurements in person. In contrast, patients can use the InBody 770 to obtain measurements by themselves in the standing position, which may be more convenient. Therefore, this study compared the measurements of hemodialysis patients’ estimated target weight and ECW/TBW obtained lying down using the S10 to those obtained in the standing position using the 770.

Methods

This study was conducted among maintenance hemodialysis patients at Chuncheon Sacred Heart Hospital in October 2020. Measurements from 56 patients before and after hemodialysis were obtained using the 2 machines. Each (S10 or 770) estimated target weight, both pre- and post-hemodialysis, was considered ideal when the ECW/TBW ratio was 0.380. R² was calculated and the Bland-Altman test was performed.

Results

The patients’ median age was 64 years old, and 51% were men. The actual ultrafiltration was 2 kg, and the mean TBW change measured using the InBody devices was 1.5 L (R² = 0.718) for the S10 and 1.7 L (R² = 0.616) for the 770. The estimated target weight at pre- and post-hemodialysis showed a remarkably high correlation with the patients’ actual pre- and post-hemodialysis weight (R² > 0.095). The correlation between these measurements (lying vs. standing) before and after hemodialysis was also very close (R² = 1.0000). In addition, ECW/TBW had a good correlation (R2 ≥ 0.970) The Bland-Altman test of dry weight and ECW/TBW yielded similar results.

Conclusions

This study showed that patients’ estimated target weights in the lying position using the InBody S10 device and in the standing position using the InBody 770 device were consistent in both pre- and post-hemodialysis states.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02737-3.

Human Serum Betaine and Associated Biomarker Concentrations Following a 14 Day Supplemental Betaine Loading Protocol and during a 28 Day Washout Period: A Pilot Investigation

Several previous investigations have employed betaine supplementation in randomized controlled crossover designs to assess its ostensible ergogenic potential. Nevertheless, prior methodology is predicated on limited pharmacokinetic data and an appropriate betaine-specific washout period is hitherto undescribed. The purpose of the present pilot investigation was therein to determine whether a 28 day washout period was sufficient to return serum betaine concentrations to baseline following a supplementation protocol. Five resistance-trained men (26 ± 6 y) supplemented with 6 g/day betaine anhydrous for 14 days and subsequently visited the lab 10 additional times during a 28 day washout period. Participants underwent venipuncture to assess serum betaine and several other parameters before (PRE) and periodically throughout the washout timeframe (POST0, -4, -7, -10, -13, -16, -19, -22, -25 and -28). All analyses were performed at a significance level of p < 0.05. While analyses failed to detect any differences in any other serum biomarker (p > 0.05), serum betaine was significantly elevated from PRE-to-POST0 (p = 0.047; 2.31 ± 1.05 to 11.1 ± 4.91 µg·mL−1) and was statistically indistinguishable from baseline at POST4 (p = 1.00). Nevertheless, visual data assessment and an inability to assess skeletal muscle concentrations would otherwise suggest that a more conservative 7 day washout period is sufficient to truly return both serum-and-skeletal muscle betaine content to pre-supplementation levels.

Extracellular water to total body water ratio may mediate the association between phase angle and mortality in patients with cancer cachexia: A single-center, retrospective study

BACKGROUND & AIMS

Recently, prognostic factors for cancer cachexia patients have been reported. We hypothesized that phase angle (PhA), which is measured by bioelectrical impedance analysis (BIA), might be a promising marker for assessing the nutritional status and prognosis of cancer patients. This study aimed to evaluate the predictive utility of PhA, which is mediated by several BIA factors and other anthropometric parameters, such as calf circumference, for the prognosis of cancer cachexia patients.

METHODS

Consecutive patients (114, both outpatients and inpatients) with an unselected stage of cancer cachexia were recruited between July 2018 and December 2019 in Fujita Health University Hospital for this retrospective cohort study. Their mean age was 74.0 years (standard deviation, 8.5); among the total, 70 were men and 44 women. A time-dependent Cox proportional-hazards regression analysis (adjusted for age and sex) was performed to assess the following: 1) the association between potential mediators and mortality; 2) the association between five PhAs and statistically significant mediators from 1); and 3) the association between the five PhAs and mortality. Finally, Kaplan-Meier survival curves were constructed and compared between the two groups based on the patients' median baseline ratio of extracellular water (ECW) to total body water (TBW) using a log-rank test.

RESULTS

The ECW/TBW ratio (hazard ratio [HR] per 1-interquartile range [IQR] increase: 2.87; 95% confidence interval [CI]: 1.46, 5.46; p < 0.001) and skeletal muscle mass index (HR per 1-IQR increase: 0.67; 95% CI: 0.51, 0.89; p = 0.001) were associated with mortality. All five PhAs were associated with the ECW/TBW ratio (p < 0.001). Before adjustment for the ECW/TBW ratio, all five PhAs were associated with mortality (p < 0.001); only the association of the PhAs of the left arm and the trunk retained the statistical significance after adjusting for confounders (p < 0.05). The median survival times in the low (370 days; 95% CI: 168, not calculated) and high ECW/TBW groups (101 days; 95% CI: 61, 219) differed significantly (p < 0.001).

CONCLUSIONS

The association between PhA and mortality in cancer cachexia patients was largely mediated by the ECW/TBW ratio. We believe that adjusting PhA for the ECW/TBW ratio may improve the prognostication of cancer patients with cachexia, ultimately improving their palliative care.

Comparison of body water status and its distribution in patients with non-septic infection, patients with sepsis, and healthy controls

Objective

Although fluid resuscitation is the cornerstone of treatment for sepsis, the role of body water status in sepsis is poorly understood. This study aimed to understand how body water and its distribution are modified in patients with sepsis and those with non-septic infection compared to healthy individuals.

Methods

Two groups of adults presumed to have non-septic infection (n=87) and sepsis (n=54) were enrolled in this prospective study in a single emergency department, and they were compared to sex-, age-, and height-matched (1:3 ratio) healthy controls (n=11,190) from retrospective data in a health promotion center. Total body water (TBW), intracellular water (ICW), and extracellular water (ECW), determined using direct segmental multi-frequent bioelectrical impedance analysis (InBody S10) were expressed as indices for normalization by body weight (BW). The ratio of ECW to TBW (ECW/TBW) was evaluated to determine body water distribution.

Results

TBW/BW, ICW/BW, and ECW/BW were significantly higher in the non-septic infection group than in the healthy group (P<0.001), but ECW/TBW was not significantly different (P=0.690). There were no differences in TBW/BW and ICW/BW between the sepsis and healthy groups (P=0.083 and P=0.963). However, ECW/BW and ECW/TBW were significantly higher in the sepsis group than in the healthy group (P<0.001).

Conclusion

Compared to the healthy group, the ratio of body water to BW was significantly increased in the non-septic infection group, while ECW/BW and ECW/TBW were significantly increased in the sepsis group. These indices could be utilized as diagnostic variables of body water deficit in septic patients.

Effect of Empagliflozin Versus Placebo on Body Fluid Balance in Patients With Acute Myocardial Infarction and Type 2 Diabetes Mellitus: Subgroup Analysis of the EMBODY Trial

BACKGROUND

The development of heart failure is associated with fluid balance, including that of extracellular water (ECW) and intracellular water (ICW). This study determined whether sodium-glucose cotransporter 2 inhibitors affect fluid balance and improve heart failure in patients after acute myocardial infarction.

METHODS AND RESULTS

EMBODY was a prospective, randomized, double-blinded, placebo-controlled trial of Japanese patients with acute myocardial infarction and type 2 diabetes. Overall, 55 patients who underwent bioelectrical impedance analysis were randomized to receive once daily 10 mg empagliflozin or placebo 2 weeks after acute myocardial infarction onset. We investigated the time course of body fluid balance measured using the bioelectrical impedance analysis device, InBody. The primary end points were changes in body fluid balance from weeks 0 to 24. Changes between baseline and week 24 in the empagliflozin and placebo groups were -0.21 L (P = .127) and +0.40 L (P = .001) in ECW (P = .001) and -0.23 L (P = .264) and +0.74 L (P < .001) in ICW (P < .001), respectively. In a stratified analysis, the rise in ECW and ICW was significantly attenuated in the empagliflozin group in contrast to the placebo group in participants with a body mass index of 25 or higher but not in those with a body mass index of less than 25.

CONCLUSIONS

Early sodium-glucose cotransporter 2 inhibitor administration may attenuate changes in ECW and ICW.

Comparison of lean mass indices as predictors of mortality in incident peritoneal dialysis patients

Background

Few studies have considered optimal adjusted lean mass indices for prediction of clinical outcomes in peritoneal dialysis (PD) patients. We aimed to evaluate clinical variables using various adjusted indices in PD patients.

Methods

Total 528 incident PD patients were included. Lean mass was measured using dual energy X-ray absorptiometry. Appendicular lean mass (ALM) was calculated using the sum for both upper and lower extremities. Each ALM index was calculated using ALM per body weight (ALM/BW), height squared (ALM/Ht²), or body mass index (ALM/BMI). Limb/trunk lean mass (LTLM) ratio was defined as the sum for both upper and lower extremities divided by trunk lean mass.

Results

A total of 528 patients were analyzed men: 286, women: 242. In area under the receiver operating characteristic curve analyses, LTLM alone was associated with 1 year mortality. In the LTLM ratio, the cut-off value for 1-year mortality was ≤ 0.829 in men and ≤ 0.717 in women, respectively. In both sexes, LTLM ratio alone showed statistical significance in all-cause mortality in both univariate and multivariate Cox-regression analyses. Compared with other indices, the LTLM ratio was independent of edema and fat in both sexes. Edema- and C-reactive protein-adjusted correlation analysis showed that LTLM ratio alone was associated with serum albumin in men. Although statistical significance was not obtained for women, the correlation coefficient was highest for the LTLM ratio compared with other indices.

Conclusion

Among various indices using lean mass, LTLM ratio was independent of volume status and fat mass and was associated with mortality in incident PD patients.

Impact of extracellular-to-intracellular fluid volume ratio on albuminuria in patients with type 2 diabetes: A cross-sectional and longitudinal cohort study

AIMS/INTRODUCTION

Body fluid volume imbalance is common in patients with kidney failure, and is associated with all-cause mortality. This study aimed to investigate the association between fluid volume imbalance and albuminuria in patients with type 2 diabetes mellitus without kidney failure.

MATERIALS AND METHODS

Using data from one cohort study, a baseline cross-sectional study of 432 participants and a longitudinal cohort study of 368 participants who could follow up was carried out. Body fluid imbalance was determined by measuring the extracellular water (ECW)-to-intracellular water (ICW) ratio (ECW/ICW) using bioelectrical impedance analysis. A change in the urinary albumin-to-creatinine ratio (ACR) was defined as the ratio of urinary ACR at follow up to that at baseline. The ECW/ICW ratio was compared with the level of albuminuria.

RESULTS

In this cross-sectional study, the ECW/ICW ratio increased with the level of albuminuria. There was an association between the ECW/ICW ratio and logarithms of urinary ACR after adjusting for covariates (β = 0.205, P < 0.001). Furthermore, the ECW/ICW ratio was associated with a change in the urinary ACR after adjusting for covariates (β = 0.176, P = 0.004) in this longitudinal study. According to the receiver operating characteristic curve, the optimal cut-off point of the ECW/ICW ratio for incident macroalbuminuria, defined as ACR >300 mg/gCr, was 0.648 (area under the curve 0.78, 95% confidence interval 0.58-0.90).

CONCLUSIONS

The ECW/ICW ratio is independently associated with the level of albuminuria in patients with type 2 diabetes mellitus without kidney failure. This reinforces the importance of monitoring fluid balance in patients with type 2 diabetes mellitus.

Assessment of Body Composition and Dietary Intake in Nursing-Home Residents: Could Lessons Learned from the COVID-19 Pandemic Be Used to Prevent Future Casualties in Older Individuals?

The population of older adults, especially those living in the nursing homes, is growing. The sedentary lifestyle and possible poor nutrition in nursing homes place residents (NHRs) at risk for body composition impairments, malnutrition, and, subsequently, numerous chronic diseases. The aim of this study was to assess body composition (including body fluids) and dietary intake in NHRs. The association between osteosarcopenic adiposity syndrome (OSA) and its components, osteopenic adiposity (OA), sarcopenic adiposity (SA), and adiposity-only (AD), and specific macro- and micro-nutrients was evaluated as well. The study included 84 participants (82.1% women), aged 65.3-95.2 years. Body composition was assessed with an advanced bioelectrical impedance device BIA-ACC® and dietary intake was assessed via 24-h recall and analyzed using "Nutrition" software. The majority (95%) of participants were overweight with a high body fat and low muscle and bone mass, leading to a high prevalence of OSA (>50%), OA (13%), and AD (26%). There were only a few participants with SA, and they were not analyzed. The highest extracellular water/total body water ratio was observed in the OSA participants, indicating a heightened inflammatory state. Participants in all three body composition categories had a similar nutrient intake, with protein, fiber, omega-3 fatty acids, and almost all micronutrients being far below recommendations. In conclusion, a high prevalence of OSA among NHRs accompanied by a poor dietary intake, could place these residents at a very high risk for COVID-19 infections. Therefore, optimization of body composition and nutritional status should be included along with standard medical care in order to provide better health maintenance, particularly in the COVID-19 era.

Feasibility of segmental bioelectrical impedance analysis for mild- to moderate-degree breast cancer-related lymphedema: Correlation with circumferential volume measurement and phase angle

ABSTRACT

Segmental multi-frequency bioelectrical impedance analysis (s-MFBIA) has been adopted recently to evaluate the volume of breast cancer-related lymphedema (BCRL). This procedure uses the segmental phase angle (s-PhA) as an indicator of cellular integrity. In the smaller-built Asian population, the BCRL often has a small volume difference and can be overlooked by tape circumference volume measurement (TVM). This study aimed to investigate the clinical feasibility of s-MFBIA for the assessment of lymphedema severity compared with TVM and evaluate the association between lymphedema severity and cellular integrity of the affected arm based on s-PhA values for a patient with mild- to moderate-degree BCRL.Segmental PhA and extracellular water (ECW)/total body water (TBW) ratio of bilateral arms were measured using InBody S10, an s-MFBIA device, in 128 BCRL patients. Inter-limb volume ratio was measured using TVM. The inter-limb ECW/TBW ratio was correlated with inter-limb volume ratio. Inter-limb ECW/TBW ratio and inter-limb volume ratio were then correlated with inter-limb PhA ratio to demonstrate the association between lymphedema severity and arm cellular integrity.The inter-limb ECW/TBW ratio and inter-limb volume ratio were positively correlated (r = 0.654, P < .001). The same result was obtained after adjusting for age, body mass index, postoperative survival, and duration of lymphedema (r = 0.636, 0.653, 0.652, and 0.648, P < .001). The inter-limb PhA ratio demonstrated significant negative correlation with inter-limb ECW/TBW ratio and inter-limb volume ratio (r = -0.896, -0.562, P < .001).s-MFBIA has high consistency with the conventional TVM method, and its relation to cellular integrity by segmental PhA enables better understanding of the cellular state of the affected limb in mild- to moderate-degree BCRL. Therefore, it is clinically feasible for severity assessment and monitoring of mild- to moderate-degree BCRL in smaller-built Asian patients.

Total Body and Extracellular Water Measures Are Unrelated to Cramp Sensitivity in Euhydrated Cramp-Prone Individuals

Earp, JE, Stearns, RL, Agostinucci, J, Lepley, AS, and Ward-Ritacco, CL. Total body and extracellular water measures are unrelated to cramp sensitivity in euhydrated cramp-prone individuals. J Strength Cond Res XX(X): 000-000, 2020-Spectral bioelectrical impedance analysis (BIA) is a valid and noninvasive tool for measuring total body water (TBW), intracellular water (ICW), and extracellular water (ECW). As altered hydration and electrolyte imbalance have been proposed as one of 2 etiologies for exercise-associated muscle cramps (EAMC), the purpose of this study was to determine if distribution of body water is related to cramp sensitivity in similarly hydrated cramp-prone individuals. To this end, 11 euhydrated subjects who regularly experience EAMC had their relative TBW, ICW, and ECW assessed using 8-pole spectral BIA. Subjects' cramp sensitivity was then assessed by electrically stimulating the tibial nerve at increasing frequencies until a muscle cramp occurred, allowing for the determination of the threshold frequency (TF) at which the cramp occurred. It was observed that TF was not significantly related to TBW (r = 0.087, p = 0.368), ICW (r = 0.105, p = 0.338), ECW (r = 0.087, p = 0.368), or ECW:TBW (r = 0.147, p = 0.280). As cramp etiology is poorly understood, these results add to a growing body of literature questioning the role of hydration and electrolyte imbalance in EAMC. Although fluid distribution may be unrelated to TF in those who commonly experience EAMC, additional research is needed to compare those who commonly experience cramps (athletes as well as individuals with specific neuropathies or pharmacologically induced cramps) with those who do not experience cramps and to determine if acute shifts in body water compartmentalization are related to changes in cramp sensitivity.

Sample Preparation Methods for Lipidomics Approaches Used in Studies of Obesity

Obesity is associated with alterations in the composition and amounts of lipids. Lipids have over 1.7 million representatives. Most lipid groups differ in composition, properties and chemical structure. These small molecules control various metabolic pathways, determine the metabolism of other compounds and are substrates for the syntheses of different derivatives. Recently, lipidomics has become an important branch of medical/clinical sciences similar to proteomics and genomics. Due to the much higher lipid accumulation in obese patients and many alterations in the compositions of various groups of lipids, the methods used for sample preparations for lipidomic studies of samples from obese subjects sometimes have to be modified. Appropriate sample preparation methods allow for the identification of a wide range of analytes by advanced analytical methods, including mass spectrometry. This is especially the case in studies with obese subjects, as the amounts of some lipids are much higher, others are present in trace amounts, and obese subjects have some specific alterations of the lipid profile. As a result, it is best to use a method previously tested on samples from obese subjects. However, most of these methods can be also used in healthy, nonobese subjects or patients with other dyslipidemias. This review is an overview of sample preparation methods for analysis as one of the major critical steps in the overall analytical procedure.

Extracellular Water Ratio as an Indicator of the Development and Severity of Leg Lymphedema Using Bioelectrical Impedance Analysis

Background: This case-control retrospective study focused on the extracellular water ratio (%ECW) of lymphedemic limbs measured by bioelectrical impedance analysis (BIA) as a possible indicator of the development and severity of unilateral and bilateral leg lymphedema. Methods and Results: BIA was used to evaluate changes in %ECW due to lymphedema in female patients with unilateral secondary leg lymphedema and in healthy controls. Receiver operating characteristic (ROC) analysis was employed to assess the diagnostic ability of %ECW to distinguish leg lymphedema patients from controls. Thirty-eight female patients were eligible for inclusion along with an equal number of healthy control volunteers. The %ECW of the affected leg correlated with leg body water volume (R² = 0.28) and the water volume difference between affected and unaffected legs (R² = 0.58). The ROC analysis showed that %ECW had a high diagnostic ability as a screening tool for the development of leg lymphedema (area under the ROC curve = 0.96). A cutoff %ECW value of 40.0% could predict the presence of leg lymphedema with a sensitivity of 81.6% and specificity of 97.4%. Conclusions: %ECW value may be a simple and useful indicator of the development and severity of leg lymphedema. As a screening test, %ECW measurement can predict the presence of unilateral or bilateral leg lymphedema in a single measurement without the need for arm, contralateral leg, or previous measurements as controls.

Total body water by BIA in children and young adults with normal and excessive weight

Background

Estimation of total body water (TBW) is essential for clinical care.

Objective

Evaluation of changes in TBW by bioelectrical impedance analysis (BIA) in children and young adults with excessive weight.

Design

Data was collected in individuals aged 3–21 years with normal (n = 202) or excessive body weight (n = 133). The BIA results from individuals with normal weight were compared with two previously published studies in children by isotope dilution methods.

Results

Individuals with excessive weight had a higher mean TBW (27.87 L, SE 0.368) for height and age as compared to individuals with normal weight (23.95 L, SE 0.298), P<0.001. However, individuals with excessive weight had lower mean TBW (24.93 L, SE 0.37) for weight and body surface area (BSA) as compared to individuals with normal weight (26.94 L, SE 0.287), P<0.001. Comparison with two previously published studies showed no significant differences in mean TBW with one ((p = 1.00) but a significant difference with another study (p = 0.001).

Conclusions

Individuals with excessive weight had 16.5% higher mean TBW for height and age and 7.4% lower TBW for weight and BSA as compared to normal weight individuals. Our study validates the feasibility of data collection in pediatric outpatient setting by BIA.

Measuring maternal body composition by biomedical impedance can predict risk for gestational diabetes mellitus: a retrospective study among 22,223 women

OBJECTIVES

This study aimed to identify which element of body composition measurements taken before 17th week gestation was the strongest risk factor for gestational diabetes mellitus (GDM) in Chinese pregnant women.

DESIGN AND SETTING

A retrospective study was performed using data retrieved from the Electronic Medical Record database of Chongqing Health Center for Women and Children (China) from January 2014 to December 2015.

PARTICIPANTS

A total of 22,223 women were included with singleton pregnancies and no preexisting diabetes who underwent bioelectrical impedance analysis (BIA) before 17 gestational weeks and 75-g OGTT at 24-28 gestational weeks.

RESULTS

The prevalence of GDM from 2014 to 2015 was 27.13% (IADPSG). All indicators of BIA (total body water, fat mass, fat-free mass, percent body fat, muscle mass, visceral fat levels, proteins, bone minerals, basal metabolic rate, lean trunk mass), age, weight and body mass index (BMI) were risk factors that significantly increased the occurrence of GDM (p < .001 for all). Women older than 30 years or with a BMI more than 23, had a significantly higher GDM prevalence (34.89% and 34.77%). After adjusted covariates, visceral fat levels at the third quartile, the ORs of GDM were 1.142 (95% CI 1.032-1.263) in model I and 1.419 (95% CI 1.274-1.581) in model II used the first quartile as reference (p < .05 for both); bone minerals at the third quartile, the ORs of GDM were 1.124 (95% CI 1.020-1.238) in model I and 1.311 (95% CI 1.192-1.442) in model II (p < .05 for both). After adjusted for age, visceral fat levels and bone minerals, OR of GDM for percent body fat more than 28.77% at the third quartile was 1.334 (95% CI 1.201-1.482) in model II (p < .05 for both).

CONCLUSIONS

Visceral fat levels, bone minerals and percent body fat were significantly associated with an increased risk of GDM, providing the reference ranges of visceral fat levels, bone minerals and percent body fat as predictive factors for Chinese women to estimate the risk of GDM by BIA during pregnancy.

Steady State Hydration Levels of Career Firefighters in a Large, Population-Based Sample

OBJECTIVES

To establish the extent of steady state hypohydration among firefighters and examine factors associated with their hydration status.

METHODS

Data on 450 career firefighters from 11 randomly selected fire departments had their body composition, total body water (TBW), and hypohydration status assessed using bioelectrical impedance. Measured height and weight were used to determine body mass index (BMI) and weight classification.

RESULTS

The hypohydration rate was 17% and 94% of hypohydrated firefighters were obese. A one-unit increase in BMI was associated with an 83% greater likelihood of being hypohydrated.

CONCLUSIONS

This study indicates that steady state hypohydration is a significant issue among obese firefighters. Current hydration policies based on previous reports that most (more than 90%) firefighters are hypohydrated in the steady state should be revisited and additional, confirmatory research in this area should be conducted.

FTO Variant rs1421085 Associates With Increased Body Weight, Soft Lean Mass, and Total Body Water Through Interaction With Ghrelin and Apolipoproteins in Arab Population

Association studies have implicated single nucleotide polymorphisms (SNPs), particularly rs1421085, from the fat mass and obesity-associated (FTO) gene with body composition phenotypes, obesity, dietary intake, and physical activity in European, East Asian, and African populations. However, the impact of the rs1421085 variant has not been sufficiently tested in ethnic populations (such as Arabs) with high levels of obesity. Further, there is a lack of studies identifying biomarkers that interact with FTO. Therefore, we investigated the association of rs1421085 with obesity and body composition traits and metabolic biomarkers in Arab population. We genotyped rs1421085 SNP in 278 Arab individuals, where multiple biomarkers relating to obesity, inflammation, and other metabolic pathways were quantified. We performed genetic association tests under additive mode of inheritance using linear regression models and found association of rs1421085_C allele with higher levels of body weight, soft lean mass (SLM), and total body water. Examination (using linear regression models under dominant mode of inheritance) of correlation among biomarkers and interaction with genotypes at the variant revealed that measures of these three body composition traits were found mediated by interaction between carrier genotypes (TC+CC) and measures of ghrelin, ApoA1, and ApoB48. Lean body mass (LBM), to which SLM contributes, is an important determinant of physical strength and is a focal point in studies on sarcopenia. Low LBM is known to be associated with higher risk of cardiometabolic disorders. Thus, the finding on the FTO variant as a genetic determinant of SLM via interaction with ghrelin, ApoA1, and ApoB48 is important.

Electrolyte beverage consumption alters electrically induced cramping threshold

BACKGROUND

Recent investigations have questioned the role of hydration and electrolytes in cramp susceptibility and thus the efficacy of consuming electrolyte-rich carbohydrate beverages (EB) to control/prevent cramping.

METHODS

Nine euhydrated, cramp-prone participants had their cramp susceptibility assessed by measuring the nerve stimulation threshold frequency at which cramping occurs (TF) before and after consumption of an EB (kCal: 120, Na: 840 mg, K: 320 mg, Mg: 5 mg) and placebo beverage (PB: kCal: 5, Na: 35 mg). Cramp intensity was assessed using a verbal pain scale and poststimulation electromyography (EMG).

RESULTS

TF was greater in EB (14.86 ± 7.47 Hz) than PB (14.00 ± 5.03 Hz; P = .038) and reported pain was lower in EB (2.0 ± 0.6) than PB (2.7 ± 0.8; P = .025) while EMG was similar (P = .646).

DISCUSSION

EB consumption decreased cramp susceptibility and pain but did not prevent cramping in any participants. These results suggest that electrolyte consumption independent of hydration can influence cramp susceptibility in young people.

Nutrition-related factors associated with waiting list mortality in patients with interstitial lung disease: A retrospective cohort study

Japanese patients with interstitial lung disease (ILD) sometimes die waiting for lung transplantation (LTx) because it takes about 2 years to receive it in Japan. We evaluated nutrition-related factors associated with waiting list mortality. Seventy-six ILD patients were hospitalized in Kyoto University Hospital at registration for LTx from 2013 to 2015. Among them, 40 patients were included and analyzed. Patient background was as follows: female, 30%; age, 50.3 ± 6.9 years; body mass index, 21.1 ± 4.0 kg/m² ; 6-minute walk distance (6MWD), 356 ± 172 m; serum albumin, 3.8 ± 0.4 g/dL; serum transthyretin (TTR), 25.3 ± 7.5 mg/dL; and C-reactive protein, 0.5 ± 0.5 mg/dL. Median observational period was 497 (range 97-1015) days, and median survival time was 550 (95% CI 414-686) days. Survival rate was 47.5%, and mortality rate was 38.7/100 person-years. Cox analyses showed that TTR (HR 0.791, 95% CI 0.633-0.988) and 6MWD (HR 0.795, 95% CI 0.674-0.938) were independently correlated with mortality and were influenced by body fat mass and leg skeletal muscle mass, respectively. It is suggested that nutritional markers and exercise capacity are important prognostic markers in waitlisted patients, but further study is needed to determine whether nutritional intervention or exercise can change outcomes.

A swan song for Kt/Vurea

Dialyzer clearance of urea multiplied by dialysis time and normalized for urea distribution volume (Kt/V_urea or simply Kt/V) has been used as an index of dialysis adequacy since more than 30 years. This article reviews the flaws of Kt/V, starting with a lack of proof of concept in three randomized controlled hard outcome trials (RCTs), and continuing with a long list of conditions where the concept of Kt/V was shown to be flawed. This information leaves little room for any conclusion other than that Kt/V, as an indicator of dialysis adequacy, is obsolete. The dialysis patient might benefit more if, instead, the nephrology community concentrates in the future on pursuing the optimal dialysis dose that conforms with adequate quality of life and on factors that are likely to affect outcomes more than Kt/V. These include residual renal function, volume status, dialysis length, ultrafiltration rate, the number of intra-dialytic hypotensive episodes, interdialytic blood pressure, serum potassium and phosphate, serum albumin, and C reactive protein.

Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

OBJECTIVE

To analyze the changes in the body composition of morbidly obese patients induced by a very low-calorie diet.

METHODS

We evaluated 120 patients selected from a university hospital. Body composition was assessed before and after the diet provided during hospitalization, and changes in weight, body mass index, and neck, waist and hip circumferences were analyzed. Bioimpedance was used to obtain body fat and fat-free mass values. The data were categorized by gender, age, body mass index and diabetes diagnosis.

RESULTS

The patients consumed the diet for 8 days. They presented a 5% weight loss (without significant difference among groups), which represented an 85% reduction in body fat. All changes in body circumference were statistically significant. There was greater weight loss and a greater reduction of body fat in men, but the elderly showed a significantly higher percentage of weight loss and greater reductions in body fat and fat-free mass. Greater reductions in body fat and fat-free mass were also observed in superobese patients. The changes in the diabetic participants did not differ significantly from those of the non-diabetic participants.

CONCLUSIONS

The use of a VLCD before bariatric surgery led to a loss of weight at the expense of body fat over a short period, with no significant differences in the alteration of body composition according to gender, age, body mass index and diabetes status.

Relationship Between Skeletal Muscle Mass Indexes and Muscular Function, Metabolic Profile and Bone Mineral Density in Women with Recommendation for Bariatric Surgery

BACKGROUND AND AIM

We evaluated low skeletal muscle mass (LMM) in women prior to bariatric surgery (BS) through different skeletal muscle mass indexes (MMIs) regarding body fat percentage (BFP), handgrip strength (HS), six-minute walk test (6MWT), metabolic profile and bone mineral density (BMD).

METHODS

Women (n=62) were allocated into two groups according to LMM: obesity with low muscle mass (OLMM) or obesity with normal muscle mass (ONMM). LMM was defined by the appendicular skeletal muscle mass (ASM) adjusted for weight (ASM/wt × 100) and ASM adjusted for body mass index (ASM/BMI), considering the lowest quintile of the indexes studied.

RESULTS

OLMM was found in 30.5% by ASM/wt × 100 and 20.3% by ASM/BMI. Using the ASM/wt × 100, OLMM group had a high BFP, low HS and BMD in L1-L4, femoral neck (FN) and total femur (TF) when compared with ONMM (p < 0.05). Using ASM/BMI, OLMM group had increased BFP, reduced HS and 6MWT in comparison to ONMM (p < 0.05). Metabolic profile was similar between OLMM and ONMM groups by the two MMIs. MMIs were negatively correlated with BFP (p < 0.05) and positively correlated with HS (p < 0.05), and none of them with 6MWT (p > 0.05). ASM/wt × 100 was positively correlated with all BMD sites assessed (p < 0.05). There was positive correlation between ASM/wt × 100 and ASM/BMI.

CONCLUSION

OLMM identified by the ASM/wt × 100 and ASM/BMI had higher adiposity and lower HS. Using ASM/BMI, we found that OLMN had a poor physical performance, while the ASM/wt × 100 identified a lower BMD at all sites.

Validity of multi-frequency bioelectric impedance methods to measure body composition in obese patients: a systematic review

OBJECTIVE

Excessive lean tissue loss following bariatric surgery may pose serious metabolic consequences. Accurate methods to assess body composition following bariatric surgery are required. This review aimed to investigate if multi-frequency bioelectric impedance (MF-BI) is a valid tool to determine body composition in obese patients.

METHODS

MEDLINE, EMBASE, CINAHL and CENTRAL databases were searched until March 2017. Included studies were published in English with obese (body mass index (BMI) ≥ 30 kg/m²) adults measuring body composition with MF-BI methods in comparison with reference methods. Exclusions were pregnancy, animal studies, non-English language studies, single frequency BI. A total of 6395 studies were retrieved.

RESULTS

Sixteen studies were eligible for inclusion. Sample sizes ranged from 15 to 157, with BMI 26-48 kg/m². MF-BI underestimated fat mass (FM) in 11 studies and overestimated fat-free mass (FFM) in nine studies in comparison with reference methods. Correlations of absolute values from MF-BI and reference methods for FM and FFM were high, however, agreement was lower at an individual level. When adjustments for BMI were made to machine algorithms, measurement accuracy improved. Significant heterogeneity was evident among included studies.

CONCLUSIONS

This review found that MF-BI is reliable for use at a group level. Obese-specific adjustment of algorithms for MF-BI machines increases the accuracy of absolute measures of body composition in obese individuals, improving their utility in the clinical setting. Multiple variables contributed a lack of consistency among studies included, highlighting the need for more robust studies that control confounding variables to establish clear validity assessment.

Comparison of body composition assessment by DXA and BIA according to the body mass index: A retrospective study on 3655 measures

BACKGROUND AND AIMS

Body composition assessment is often used in clinical practice for nutritional evaluation and monitoring. The standard method, dual-energy X-ray absorptiometry (DXA), is hardly feasible in routine clinical practice contrary to Bioelectrical Impedance Analysis (BIA) method. We thus aimed to compare body composition assessment by DXA and BIA according to the body mass index (BMI) in a large cohort.

METHODS

Retrospectively, we analysed DXA and BIA measures in patients followed in a Nutrition Unit from 2010 to 2016. Body composition was assessed under standardized conditions in the morning, after a fasting period of 12 h, by DXA (Lunar Prodigy Advance) and BIA (Bodystat QuadScan 4000, Manufacturer's equation). Bland-Altman test was performed for each class of BMI (kg/m2) and fat mass and fat free mass values were compared using Kruskal-Wallis test. Pearson correlations were also performed and the concordance coefficient of Lin was calculated.

RESULTS

Whatever the BMI, BIA and DXA methods reported higher concordance for values of FM than FFM. Body composition values were very closed for patients with BMI between 16 and 18,5 (difference < 1kg). For BMI > 18,5 and BMI < 40, BIA overestimated fat free mass from 3,38 to 8,28 kg, and underestimated fat mass from 2,51 to 5,67 kg compared with DXA method. For BMI ≥ 40, differences vary with BMI. For BMI < 16, BIA underestimated fat free mass by 2,25 kg, and overestimated fat mass by 2,57 kg. However, limits of agreement were very large either for FM and FFM values, irrespective of BMI.

CONCLUSION

The small bias, particularly in patients with BMI between 16 and 18, suggests that BIA and DXA methods are interchangeable at a population level. However, concordance between BIA and DXA methods at the individual level is lacking, irrespective of BMI.