Multifrequency bioelectrical impedance estimates the distribution of body water

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.

Waistline to thigh circumference ratio as a predictor of MAFLD: a health care worker study with 2-year follow-up

BACKGROUND

This study aimed to determine whether the waist-to-thigh ratio (WTTR) is associated with the incidence of metabolic-associated fatty liver disease (MAFLD) in health care workers.

METHODS

There were 4517 health care workers with baseline data and results from 2 follow-up examinations. We divided the subjects into 3 groups according to baseline WTTR and used the Cox hazard regression model to estimate MAFLD risk.

RESULTS

The WTTRs were categorized by tertiles at baseline using the values 1.58 and 1.66. Patients with higher WTTR tended to have significantly greater values for the following factors, body mass index (BMI), fasting blood glucose (FPG), systolic blood pressure, diastolic blood pressure, total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C) and neck circumference. The incidence of MAFLD significantly increased with increasing WTTR tertiles (5.74%, 12.75% and 22.25% for the first, second and third tertiles, respectively, P < 0.05 for trend). Kaplan-Meier(K-M) survival analysis revealed a significant tendency towards increased MAFLD risk with increasing WTTR tertile. In the fully adjusted model, the hazard ratios (95% CIs) for MAFLD in the second, third WTTR tertiles compared with the first quartile were 2.17(1.58,2.98), 3.63(2.70,4.89), respectively, third neck circumference tertiles compared with the first quartile were 2.84(1.89,4.25), 8.95(6.00,13.35), respectively. Compared with those of individuals with a BMI > 23 kg/m2, the associations between WTTR and MAFLD incidence were more pronounced in subjects with a BMI < 23 kg/m2. Similarly, the difference in neck circumference was more pronounced in these patients with a BMI < 23 kg/m2.

CONCLUSIONS

Our results revealed that the WTTR is an independent risk factor for MAFLD, and there was a dose‒response relationship between the WTTR and MAFLD risk. The neck circumference was significantly different in subjects with a BMI < 23 kg/m2. This approach provides a new way to predict the incidence rate of MAFLD.

Influence of aging on extracellular water-to-total body water ratio in community-dwelling females

BACKGROUND & AIMS

The European Working Group of Sarcopenia in Older People 2 has emphasized the significance of evaluating not only muscle mass but also muscle quality as a diagnostic criterion for sarcopenia. The extracellular water-to-total body water ratio (ECW/TBW), measured using bioelectrical impedance analysis (BIA), has recently received attention as an indicator of muscle quality. However, the influence of aging on the ECW/TBW remains unclear. If ECW/TBW increases with age, it is important to know whether the timing of the decrease in SMI and the increase in ECW/TBW are the same or different. This study aimed to investigate the influence of aging on ECW/TBW in community-dwelling females.

METHODS

This cross-sectional study included 237 community-dwelling females aged 20-89 years who could perform activities of daily living independently. ECW/TBW and SMI were measured using BIA. Multiple linear regression analyses of ECW/TBW and SMI were conducted. Age, body mass index (BMI), number of medications, pain, and medical history were considered independent variables in the multiple linear regression. The participants were divided into three (20-39, 40-64, and 65-89 years) or four (20-39, 40-64, 65-74, and 75-89 years) groups based on age. Analysis of covariance adjusted for the BMI, number of medications, pain, and medical history was conducted to determine the differences in ECW/TBW and SMI among the three or four groups.

RESULTS

In the multiple linear regression analysis, age was significantly and independently associated with ECW/TBW and SMI. When the participants were divided into three groups based on age, an increase in ECW/TBW and a decrease in SMI in the 65-89-year group were confirmed compared with the 20-39 and 40-64-year groups. When the participants were divided into four groups based on age, an increase in ECW/TBW in the 75-89-year group was confirmed compared with the 65-74-year group. However, there were no significant differences in SMI among the four groups.

CONCLUSIONS

This study revealed that ECW/TBW increases with aging in community-dwelling females. Moreover, the negative influences of aging were confirmed earlier in ECW/TBW than in SMI. Assessing muscle mass alone may not be adequate to capture the influences of aging on muscle composition, and evaluating ECW/TBW may be crucial for diagnosing sarcopenia.

Usefulness of the Global Leadership Initiative on malnutrition (GLIM) criteria in preoperative nutritional assessment of patients with primary lung cancer

BACKGROUND AND AIMS

The Global Leadership Initiative on Malnutrition (GLIM) developed a new method for evaluating malnutrition; however, no consensus has been reached regarding the use of these criteria. Therefore, this study aimed to investigate the association between nutritional status assessed using the GLIM criteria and outcomes of lung cancer after surgery.

METHODS

Patients with non-small cell lung cancer who underwent lung resection and bioelectrical impedance analysis to estimate muscle mass before surgery were included. Their background, pathological stage, recurrence, and prognosis were investigated. Patients were divided into two groups according to the GLIM criteria: normal nutrition and malnutrition groups.

RESULTS

The normal and malnutrition groups comprised 110 and 88 patients, respectively. Malnutrition was significantly associated with poor overall survival after surgery (P = 0.025) but not with disease-free survival. Multivariate analysis showed that malnutrition (hazard ratio [HR]:2.374, P = 0.020), advanced pathological stage of lung cancer (HR: 1.919, P = 0.002), and the presence of postoperative complications (HR: 2.035, P = 0.047) were significantly associated with poor overall survival.

CONCLUSION

Malnutrition assessed using the GLIM criteria was associated with the prognosis of patients with postoperative non-small cell lung cancer. Preoperative assessment using the GLIM criteria would allow for effective nutritional and rehabilitative interventions to improve prognosis.

Effect of body fat mass loss on prognosis of radical resection for pancreatic ductal adenocarcinoma based on bioelectrical impedance analysis

BACKGROUND

Few reports have performed a prognostic analysis based on bioelectrical impedance analysis in patients with radical resection of pancreatic ductal adenocarcinoma (PDAC), and its usefulness in prognostic analysis remains unclear. This study aimed to evaluate body composition changes in patients undergoing radical resection for PDAC and analyze its impact on prognosis.

METHODS

The medical records of radical resection for patients with PDAC were retrospectively reviewed, and the parameters of body composition, including body weight, skeletal muscle mass, body fat mass (BFM), and extracellular water-total body water ratio, from preoperatively to 12 months postoperatively, for each surgical procedure were measured based on direct segmental multifrequency bioelectrical impedance analysis with an InBody 770 (InBody Inc., Tokyo, Japan) device. The clinicopathological and prognostic factors were analyzed.

RESULTS

Among 79 patients who underwent radical resection for PDAC, 36 (46%), 7 (8%), and 36 (46%) underwent pancreatoduodenectomy, total pancreatectomy, and distal pancreatectomy, respectively. The multivariate overall survival analysis demonstrated that BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021), lymph node metastasis (p = 0.014), and non-adjuvant chemotherapy (p <  0.001) were independent poor prognostic factors. Multivariate analysis revealed that preoperative BFM < 12 kg and preoperative albumin < 3.5 g/dL were independently associated with BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021 and p = 0.047, respectively).

CONCLUSIONS

Loss of BFM in the early postoperative period may have a poor prognosis in radical resection of PDAC.

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.

Using hyperhomocysteinemia and body composition to predict the risk of non-alcoholic fatty liver disease in healthcare workers

Purpose

This study investigated associations between serum homocysteine levels, body composition, and the probability of having nonalcoholic fatty liver disease (NAFLD) in Chinese healthcare workers.

Patients and Methods

A total of 4028 healthcare workers were enrolled in this study, and all underwent a physical examination. Body composition was measured using multifrequency bioelectrical impedance analysis.

Results

There were 1507 NAFLD patients (72.26% male, 27.74% female) and 2521 controls (39.83% male, 60.17% female). Body mass index (BMI), waistline, neck-circumference (NC), abdominal visceral fat area (AVFA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), glucose (Glu), homocysteinemia (hcy) were higher in the NAFLD group than controls. Additionally, the skeletal-muscle was associated with a lower risk of NAFLD, whereas BMI, waistline, NC, hyperhomocysteinemia (HHcy) were associated with a higher risk of NAFLD. The best NC cut-off point for NAFLD was 34.45 cm (sensitivity 83.3% and specificity 83.9%) in women with HHcy, and the best skeletal-muscle content cut-off point for NAFLD was 41.335% (sensitivity 74.2% and specificity 65.6%) in men with HHcy.

Conclusion

Interactions between skeletal-muscle content, NC, and HHcy may affect the incidence of NAFLD in healthcare workers. This may provide a novel approach for diagnosing NAFLD.

Automated lung ultrasound image assessment using artificial intelligence to identify fluid overload in dialysis patients

BACKGROUND

Fluid assessment is challenging, and fluid overload poses a significant problem among dialysis patients, with pulmonary oedema being the most serious consequence. Our study aims to develop a simple objective fluid assessment strategy using lung ultrasound (LUS) and artificial intelligence (AI) to assess the fluid status of dialysis patients.

METHODS

This was a single-centre study of 76 hemodialysis and peritoneal dialysis patients carried out between July 2020 to May 2022. The fluid status of dialysis patients was assessed via a simplified 8-point LUS method using a portable handheld ultrasound device (HHUSD), clinical examination and bioimpedance analysis (BIA). The primary outcome was the performance of 8-point LUS using a portable HHUSD in diagnosing fluid overload compared to physical examination and BIA. The secondary outcome was to develop and validate a novel AI software program to quantify B-line count and assess the fluid status of dialysis patients.

RESULTS

Our study showed a moderate correlation between LUS B-line count and fluid overload assessed by clinical examination (r = 0.475, p < 0.001) and BIA (r = 0.356. p < 0.001). The use of AI to detect B-lines on LUS in our study for dialysis patients was shown to have good agreement with LUS B lines observed by physicians; (r = 0.825, p < 0.001) for the training dataset and (r = 0.844, p < 0.001) for the validation dataset.

CONCLUSION

Our study confirms that 8-point LUS using HHUSD, with AI-based detection of B lines, can provide clinically useful information on the assessment of hydration status and diagnosis of fluid overload for dialysis patients in a user-friendly and time-efficient way.

Correlation of Percentage Body Fat, Waist Circumference and Waist-to-Hip Ratio with Abdominal Muscle Strength

Sedentary lifestyle and consumption of high-fat foods have become widespread, especially in the urban population. This leads to a reduction in lean body mass and increased body fat. The correlation between body fat indices and low back pain has been less explored and documented. The aim of this study was to identify the correlation between the percentage of body fat, waist circumference and waist-to-hip ratio and abdominal muscle strength. Percentage of body fat was estimated by using the body composition analyzer method using Tanita BC-545 Innerscan Segmental Body Composition. Waist-to-hip ratio was calculated by dividing the waist circumference by hip circumference. Abdominal muscle (rectus abdominis and external oblique) strength was measured by maximum voluntary isometric contraction as measured by surface electromyography. A positive correlation was observed between waist circumference and the percentage of body fat, while a negative correlation was observed between the average maximum voluntary isometric contraction of rectus abdominis and external oblique muscles and the percentage of body fat. Individuals with a high percentage of body fat tend to have higher fat distribution over the abdominal region and decreased abdominal muscle strength. Therapists should emphasize the use of abdominal muscles in individuals with high body fat in order to reduce the associated risk of the development of poor posture and low back pain.

Auxiliary diagnosis of subepithelial lesions by impedance measurement during endoscopic ultrasound-guided fine-needle biopsy

BACKGROUND AND AIMS

EUS-guided FNA/biopsy (EUS-FNA/B) is the citerion standard for diagnosing subepithelial lesions (SELs); however, its diagnostic ability for SELs <20 mm is low. We developed a new diagnostic method to differentiate between GI stromal tumor (GIST) and non-GIST by measuring high-frequency impedance (H-impedance) using an EUS-FNB needle.

METHODS

The H-impedance of gastric epithelial neoplasms from 16 cases were measured with a conventional impedance probe to confirm whether H-impedance is clinically useful for assessing cell density (study 1). The H-impedance values of exposed SELs from 25 cases with use of the conventional probe (study 2) and nonexposed SELs from 20 cases with use of the EUS-FNB needle probe (study 3) were measured to determine the diagnostic ability of H-impedance for differentiating GISTs from non-GISTs.

RESULTS

H-impedance significantly positively correlated with cell density (P = .030) (study 1). The H-impedance of GIST (99.5) measured with a conventional probe was significantly higher than with those of the muscular layer (82.4) and leiomyoma (89.2) (P < .01) (study 2). The H-impedance of GIST measured with the EUS-FNB needle was also significantly higher than that of leiomyoma (GIST: 80.2 vs leiomyoma, 71.8; P = .015). The diagnostic yield of the impedance method for differentiating GISTs from non-GISTs had 94.4% accuracy, 88.9% sensitivity, 100% specificity, and 0.95 area under the curve. Diagnostic ability was not affected by lesion size (P = .86) (study 3).

CONCLUSION

Auxiliary differential diagnosis between gastric GISTs and non-GISTs by the H-impedance measurement during EUS-FNB could be a good option, especially when the lesion is <20 mm.

Comparison of intermittent pneumatic compression device and compression stockings for workers with leg edema and pain after prolonged standing: a prospective crossover clinical trial

BACKGROUND

During prolonged standing, insufficient calf muscle pumping accompanies venous stasis and hypertension in the lower legs, resulting in valve dysfunction, venous wall problems, and sub-sequent inflammation. Compression therapy, which includes medical compression stockings (MCS) and mechanical intermittent pneumatic compression (IPC), is one of the most effective therapeutic interventions for treating chronic venous diseases. This study aimed to compare the therapeutic effect among resting, IPC and MCS alone, and IPC with MCS in long-standing workers (> 8 h daily).

METHODS

This crossover trial was conducted with 39 participants with complaints of leg edema and pain whose work involved standing for more than 8 h daily. Four treatment protocols were established for each visit as follows: protocol A (not wear MCS during work and rest without IPC after work), protocol B (wear MCS during work and rest without IPC after work), protocol C (not wear MCS during work and treat with IPC after work), and protocol D (wear MCS during work and treat with IPC after work). The primary outcome was the visual analogue scale (VAS) score for leg pain. The secondary outcomes were leg volume (mL), circumference (cm), extracellular fluid/total body fluid (ECF/TBF), and extracellular water/total body water (ECW/TBW) through bioelectrical impedance analysis. Outcomes were assessed before work (T0), after work (T1), and 60 min after intervention (T2).

RESULTS

All four protocols had significantly increased leg pain after work (T0-1) but improved 60 min after intervention (T1-2), particularly protocol C (decreased VAS by 1.9). When leg swelling was compared at T0 and T1, protocols A and C showed significant increases in leg volume and circumference, indicating significant work-induced edema, whereas protocols B and D showed no change or even a decrease. After interventions, leg volume and circumference significantly decreased in protocols A and C, although protocols B and C did not show significant improvement. The ECF/TBF and ECW/TBW of all protocols decreased after interventions.

CONCLUSIONS

Leg pain and edema after prolonged standing (T1-T2) in adults were safely and effectively improved by both IPC alone and IPC with MCS. Although the use of MCS during the workday did not show improvement in leg pain immediately after work (T0-T1), both MCS with resting and MCS with IPC decreased leg pain at T1-T2 and prevented leg edema at T0-T1.

TRIAL REGISTRATION

This trial protocol was registered at the Clinical Research Information Service (KCT0005383, the date of first registration: 08/09/2020).

High precision but systematic offset in a standing bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA)

Bioelectrical impedance analysis (BIA) provides a practical method of body composition estimation for field research and weight management programmes, with devices and algorithms that have improved in recent years. We compared suitability of a commercial BIA system that uses multi-frequency-based proprietary algorithms (InBody 770, Cerritos, California, USA) and a laboratory-based validated single-frequency system (Quantum IV, RJL Systems, Clinton Township, Michigan, USA) with dual-energy X-ray absorptiometry (DXA) (iDXA, GE Lunar, Madison, Wisconsin, USA). Volunteers included fit non-obese active duty US Marines (480 men; 315 women), assessed by DXA and the two BIA systems. Both RJL and InBody BIA devices predicted DXA-based fat-free mass (FFM) (mean absolute error (MAE) 2.8 and 3.1 kg, respectively) and per cent body fat (%BF) (MAE 3.4% and 3.9%, respectively), with higher correlations from the InBody device (r²=0.96 (%BF) and 0.84 (FFM)) versus the RJL (r²=0.92 (%BF) and 0.72 (FFM)). InBody overpredicted FFM (bias +2.7, MAE 3.1 kg) and underpredicted %BF (bias -3.4 and MAE 3.9%) versus the RJL. A 3% correction factor applied to the InBody device results provided values very close to the DXA measurements. These findings support the application of modern BIA systems to body composition goals of maximum %BF and minimum lean body mass for both men and women.

Bioelectrical impedance analysis versus physician adjustment in acute kidney injury patients to reduce intradialytic hypotension: A randomized controlled trial

Introduction

Methods

Result

Conclusion

•

Intradialytic hypotension is common during hemodialysis.

•

Bioimpedance spectroscopy can help assess fluid status in critically ill patients.

•

BIA-guided protocol can reduce significantly the incidence of IDH compared to conventional method.

Differences in extracellular fluid volume between acute heart failure patients with and without high systolic blood pressure

AIMS

Some reports have suggested that hypertensive acute heart failure (AHF) is caused by intravascular congestion, not interstitial congestion. We evaluated the differences in extracellular fluid volume assessed by bioelectrical impedance analysis (BIA) between AHF patients with and without high systolic blood pressure (sBP).

METHODS

This prospective single-centre study (UMIN000030266) included 178 patients hospitalized due to AHF between September 2017 and August 2018. We calculated extracellular water (ECW), intracellular water (ICW), total body water (TBW), and ECW-to-TBW ratio (oedema index: EI) by BIA and evaluated conventional parameters as follows: weight, N-terminal pro brain natriuretic peptide values, and echocardiography parameters on admission and before discharge. One-year outcomes included all-cause death and re-admission due to heart failure. We compared patients with sBP > 140 mmHg on admission [clinical scenario 1 (CS1) group] and with sBP of ≤140 mmHg on admission (non-CS1 group).

RESULTS

The mean age of the patients was 79.5 ± 11.1 years, and 48.9% of the patients were female. EI on admission of 83 patients in the CS1 group was lower than that of 95 patients in the non-CS1 group. The change in EI from admission to before discharge was no significant in the CS1 group but was significant in the non-CS1 group. Comparing the changes from admission to before discharge between the CS1 and the non-CS1 group, delta ECW, delta ICW, delta TBW, and delta EI of the CS1 group were significantly smaller than those of the non-CS1 group. During the 1-year follow-up period after discharge of the 178 patients, the numbers of deaths and re-admissions due to acute HF were 26 (15%) and 49 (28%), respectively. Patients with high EI before discharge [>0.408 (median)] had significantly more cardiac events than patients with low EI [hazard ratio (HR): 2.15, 95% confidence interval (CI): 1.30-3.55]. Cox regression analysis revealed that higher EI as a continuous variable was significantly associated with worse outcome in non-CS1 group (HR: 1.46, 95% CI: 1.13-1.87), but not significantly associated with worse outcome in CS1 group (HR: 1.29, 95% CI: 0.98-1.69).

CONCLUSIONS

EI on admission in patients with high sBP was not elevated, and changes in ECW, ICW, TBW, and EI in patients with high sBP were smaller than those in patients without high sBP. EI measured by BIA could distinguish AHF with interstitial or intravascular congestion.

A Comparative Study of High-Frequency Bioelectrical Impedance Analysis and Dual-Energy X-ray Absorptiometry for Estimating Body Composition

Though bioelectrical impedance analysis (BIA) is a favorable tool for assessing body composition to estimate nutritional status and physical fitness, such as sarcopenia, there are accuracy issues. Hence, high-frequency (HF) BIA equipment uses an additional frequency of 2 and 3 MHz and has been developed as a commercial model. However, there are no studies validating the accuracy and safety of HF-BIA. Therefore, this study aims to assess the validity of HF-BIA in analyzing body composition relative to dual-energy X-ray absorptiometry (DEXA). Appendicular lean mass (ALM), fat-free mass (FFM), and percentage of body fat (PBF) were assessed by HF-BIA and DEXA in 109 individuals; 50.5% (n = 55) were males. The average age and body mass index (BMI) were 43.4 ± 14.7 years and 25.5 ± 6.7 in males and 44.9 ± 14.1 years and 24.0 ± 6.4 in females, respectively. The HF-BIA results showed a high correlation with the DEXA results for assessing ALM (standard coefficient beta (β) ≥ 0.95), FFM (β ≥ 0.98, coefficient of determinations (R²) ≥ 0.95), and PBF (β ≥ 0.94, R² ≥ 0.89). Body composition measured by HF-BIA demonstrated good agreement with DEXA in Korean adults.

Extracellular water-to-total body water ratio is an essential confounding factor in bioelectrical impedance analysis for sarcopenia diagnosis in women

PURPOSE

The extracellular water-to-total body water ratio (ECW/TBW) is used in bioelectrical impedance analysis (BIA) for measuring muscle mass; however, ECW/TBW may be affected by several factors common in older individuals. Here, we assessed the relationships of ECW/TBW with handgrip strength, gait speed, and skeletal muscle mass index (SMI) in older women.

METHODS

In this cross-sectional study, 73 community-dwelling women aged ≥ 65 years who could independently perform activities of daily living were included. ECW/TBW was measured using direct segmental multifrequency BIA. The participants were divided into ECW/TBW < 0.40 (n = 54) and ECW/TBW ≥ 0.40 (n = 19) groups, with the latter indicating overhydration. SMI was calculated as appendicular skeletal muscle mass/(height)² (kg/m²). The relationships of SMI with handgrip strength and gait speed were assessed using partial correlation coefficients. Age, number of medications, pain, and medical history were treated as control variables.

RESULTS

The average age of participants was 77.6 ± 6.0 years. The SMI was significantly related to handgrip strength (partial correlation coefficient = 0.293, P = 0.016) but not to gait speed (partial correlation coefficient = - 0.183, P = 0.138). Similarly, the SMI of the ECW/TBW < 0.40 group was significantly related to handgrip strength (partial correlation coefficient = 0.372, P = 0.009) but not gait speed (partial correlation coefficient = - 0.267, P = 0.066); however, the SMI of the ECW/TBW ≥ 0.40 group was not related to either variable.

CONCLUSION

ECW/TBW represents a confounding factor, which should be considered when using BIA for sarcopenia diagnosis.

Relationship between Seasonal Changes in Food Intake and Energy Metabolism, Physical Activity, and Body Composition in Young Japanese Women

We investigated seasonal changes in food intake, energy metabolism, and physical activity (PA) and explored their associations with body composition. In total, 28 women aged 20−23 years in the Kansai area of Japan participated in this year-long study spanning the winter, spring, and summer seasons. A dietary investigation was performed using the weight recording method, and the amount of histidine in the diet, which may be related to the regulation of energy intake, was calculated. Resting metabolic rate (RMR), body composition, and PA were measured using indirect calorimetry, bioelectrical impedance analysis, and uniaxial accelerometry, respectively. The results showed that energy intake was highest in winter, decreased significantly with increasing temperature, and decreased by 25% in summer. As the intake of histidine in the diet did not increase in summer, it did not seem to be involved in the suppression of energy intake. RMR was highest in winter and decreased significantly in summer by 20%. The amount of PA was low in winter, increased significantly in the spring, and decreased again in summer. Body weight increased in winter, with an accumulation of fat in the trunk and arms, and decreased in summer, with a reduction in the amount of fat. Greater energy intake and less PA in winter induced an increment in body weight despite the increase in RMR. There were no significant changes in lean body mass between the seasons; however, the muscle weight of the lower limbs increased significantly in spring and in summer compared with that in winter (p < 0.001). Thus, seasonal changes in food intake, energy metabolism, and PA occur, with resultant changes in the body composition under comfortable air-conditioned environments.

Water Distribution Changes in Complex Decongestive Treatment for Leg Lymphedema: Quantitative Evaluation by Direct Segmental Multi-Frequency Bioimpedance Analysis

Background: There is a need for a simple method for the quantitative evaluation of lymphedema swelling. In this study, we performed a direct segmental multi-frequency impedance analysis in patients with leg lymphedema.

Methods: The subjects were 36 patients (6 men and 30 women) with 46 lymphedema legs. The average age was 61 years. All patients had International Society of Lymphology stage II lymphedema. Swelling ratio and ultrasound subcutaneous tissue echo-free space (FS) were examined. InBody 770 was used to measure the extracellular water (ECW), intracellular water (ICW), and total body water (TBW) volumes. Changes before and after complex decongestive treatment (CDT) were examined.

Results: In 26 unilateral cases, the ECW, ICW, and TBW volumes of the affected legs were higher than those of the contralateral unaffected legs, and the ECW/TBW ratio was significantly higher in the affected legs (0.41) than in the contralateral unaffected legs (0.391). There was a significant correlation between the leg swelling ratio and the ECW/TBW ratio between the affected and contralateral unaffected legs (correlation coefficient=0.882). Ultrasound findings of the 46 affected legs were classified into no FS (group 0), minimal or only horizontal FS (group 1), and cobblestone-like FS (group 2). The ECW/TBW ratio of the affected legs in each group was 0.393 (14 legs), 0.407 (10 legs), and 0.426 (22 legs) respectively, demonstrating significant differences among the 3 groups. After CDT, the amount of water decreased in the affected legs and increased in the trunks and both upper limbs. The ECW/TBW ratio decreased significantly, from 0.432 to 0.414 in the affected legs, from 0.401 to 0.392 in the unaffected legs, and from 0.413 to 0.402 in the trunks. The ECW/TBW ratio had not changed and remained below 0.4 in the upper limbs.

Conclusion: The segmental water contents measured by direct segmental multi-frequency impedance analysis correlates well with the degree of lymphedema swelling, and subcutaneous echo findings and can demonstrate water distribution change before and after CDT, which is considered to be a useful quantitative evaluation method for lymphedema. (This is secondary publication from Jpn J Phlebol 2020; 31(1): 1–7.)

Home-based aerobic exercise and resistance training for severe chronic kidney disease: a randomized controlled trial

BACKGROUND

The potential effects of aerobic and resistance training in patients with severe chronic kidney disease (CKD) are not fully elucidated. This study investigated the effects of a home-based exercise programme on physical functioning and health-related quality of life (HRQOL) in patients with Stage 4 CKD, equivalent to estimated glomerular filtration rate of 15-30 mL/min/1.73 m² .

METHODS

Forty-six patients with Stage 4 CKD (median age, 73 years; 33 men) were randomly assigned to exercise (n = 23) and control (n = 23) groups. Exercise group patients performed aerobic exercise at 40-60% peak heart rate thrice weekly and resistance training at 70% of one-repetition maximum twice weekly at home for 6 months. Control patients received no specific intervention. Primary outcomes were distance in incremental shuttle walking test and HRQOL assessed using the Kidney Disease Quality of Life-Short Form questionnaire. Secondary outcomes included kidney function assessed with combined urea and creatinine clearance, urinary biomarkers, and anthropometric and biochemical parameters associated with CKD.

RESULTS

Improvement in incremental shuttle walking test was significantly greater in the exercise group compared with controls (39.4 ± 54.6 vs. -21.3 ± 46.1; P < 0.001). Among Kidney Disease Quality of Life domains, significant mean differences were observed between the exercise group and the control group in work status, quality of social interaction, and kidney disease component summary outcomes (12.76 ± 5.76, P = 0.03; 5.97 ± 2.59, P = 0.03; and 4.81 ± 1.71, P = 0.007, respectively). There were greater reductions in natural log (ln)-transformed urinary excretion of liver-type fatty acid-binding protein, ln serum C-reactive protein, and acylcarnitine to free carnitine ratio in the exercise group compared with controls, with significant between-group differences of -0.579 ± 0.217 (P = 0.008), -1.13 ± 0.35 (P = 0.003), and -0. 058 ± 0.024 (P = 0.01), respectively.

CONCLUSIONS

Our 6 month home-based exercise programme improved aerobic capacity and HRQOL in patients with Stage 4 CKD, with possible beneficial effects on kidney function and CKD-related parameters.

Obesity and myosteatosis: the two characteristics of dynapenia in patients with cirrhosis

OBJECTIVE

In patients with liver cirrhosis, the clinical characteristics of dynapenia, a condition in which skeletal muscle mass is maintained but muscle strength is reduced, are not yet known. This study aimed to clarify the characteristics of dynapenia and its impact on quality of life (QOL) in patients with liver cirrhosis.

METHODS

We retrospectively analyzed 116 patients with cirrhosis. Based on grip strength and skeletal muscle mass measured by the bioelectrical impedance analysis method, patients were divided into four groups: normal muscle status, dynapenia, pre-sarcopenia (a condition involving only low muscle mass), and sarcopenia. The characteristics of dynapenia and its influence on QOL were examined.

RESULTS

Fourteen patients had dynapenia. Liver function did not differ among the four groups. In patients with dynapenia, BMI was highest and computed tomography attenuation of skeletal muscle at the third lumbar spine vertebra was lowest among the four groups. The percentage of patients with both BMI ≥25 kg/m2 and myosteatosis was significantly higher in patients with dynapenia [9/14 (64.3%)] than in those with sarcopenia [2/23 (8.7%), P = 0.004] and pre-sarcopenia [0/18 (0%), P < 0.001] and tended to be higher than those with normal muscle status [16/61 (26.2%), P = 0.065]. The physical QOL in patients with dynapenia was as low as that in those with sarcopenia and significantly lower than that in those with normal muscle status.

CONCLUSION

Cirrhotic patients with dynapenia had high BMI and myosteatosis, and impaired physical QOL.

Short-Time Impedance Spectroscopy Using a Mode-Switching Nonsinusoidal Oscillator: Applicability to Biological Tissues and Continuous Measurement

Herein, we propose an impedance spectroscopy method using a mode-switching nonsinusoidal oscillator and apply this method for measuring the impedance of biological tissues and continuous impedance measurement. To obtain impedance spectra over a wide frequency range, we fabricated a novel nonsinusoidal oscillator incorporating binary counters and analog switches. This oscillator could periodically switch oscillation frequency through the mode switching of the feedback resistor. From the oscillation waveform at each oscillation frequency of this circuit (oscillator), we determined the impedance spectrum of a measured object using the discrete-time Fourier transform. Subsequently, we obtained the broad impedance spectrum of the measured object by merging odd-order harmonic spectral components up to the 19th order for each oscillation frequency. From the measured spectrum, the resistive and capacitive components of the circuit simulating bioimpedance were estimated with high accuracy. Moreover, the proposed method was used to measure the impedance of porcine myocardium; changes in the impedance spectrum of the myocardial tissue due to coagulation could be measured. Furthermore, rapid variations in the resistance value of a CdS photocell could be continuously measured using the proposed method.

Electrical Impedance of Upper Limb Enables Robust Wearable Identity Recognition against Variation in Finger Placement and Environmental Factors

Most biometric authentication technologies commercialized in various fields mainly rely on acquired images of structural information, such as fingerprints, irises, and faces. However, bio-recognition techniques using these existing physical features are always at risk of template forgery threats, such as fake fingerprints. Due to the risk of theft and duplication, studies have recently been attempted using the internal structure and biological characteristics of the human body, including our previous works on the ratiometric biological impedance feature. However, one may still question its accuracy in real-life use due to the artifacts from sensing position variability and electrode-skin interfacing noise. Moreover, since the finger possesses more severe thermoregulatory vasomotion and large variability in the tissue properties than the core of the body, it is necessary to mitigate the harsh changes occurring at the peripheral extremities of the human body. To address these challenges, we propose a biometric authentication method through robust feature extraction from the upper-limb impedance acquired based on a portable wearable device. In this work, we show that the upper limb impedance features obtained from wearable devices are robust against undesirable factors such as finger placement deviations and day-to-day physiological changes, along with ratiometric impedance features. Overall, our upper-limb impedance-based analysis in a dataset of 1627 measurement from 33 subjects lowered the classification error rate from 22.38% to 4.3% (by a factor of 5), and further down to 2.4% (by a factor of 9) when combined with the ratiometric features.

Evaluation of Cancer Cell Lines by Four-Point Probe Technique, by Impedance Measurements in Various Frequencies

Cell-based biosensors appear to be an attractive tool for the rapid, simple, and cheap monitoring of chemotherapy effects at a very early stage. In this study, electrochemical measurements using a four-point probe method were evaluated for suspensions of four cancer cell lines of different tissue origins: SK-N-SH, HeLa, MCF-7 and MDA-MB-231, all for two different population densities: 50 K and 100 K cells/500 μL. The anticancer agent doxorubicin was applied for each cell type in order to investigate whether the proposed technique was able to determine specific differences in cell responses before and after drug treatment. The proposed methodology can offer valuable insight into the frequency-dependent bioelectrical responses of various cellular systems using a low frequency range and without necessitating lengthy cell culture treatment. The further development of this biosensor assembly with the integration of specially designed cell/electronic interfaces can lead to novel diagnostic biosensors and therapeutic bioelectronics.

Body Muscle-to-Fat Ratio, Rather Than Fat-to-Muscle Ratio, Significantly Correlates With Measured Insulin Resistance in Patients With Type 2 Diabetes Mellitus

Background

Insulin resistance (IR) assessment is important in treating type 2 diabetes mellitus (T2DM). We thus compared body muscle-to-fat ratio (BMFR) and fat-to-muscle ratio (FMR) values against M/I values as clinical index of IR.

Methods

Subject included 118 untreated T2DM patients. Hyperinsulinemic-euglycemic clamp examination was performed to calculate the M/I as index of IR. Body composition was measured by impedance analysis using InBody770.

Results

Simple linear regression analyses confirmed correlations between M/I and BMFR (B: 0.756 (P < 0.01), coefficients of determination (R²): 0.572, mean absolute error (MAE): 3.19, and root mean squared error (RMSE): 4.14), and between M/I and FMR (B: -0.601 (P < 0.01), R²: 0.362, MAE: 3.97, and RMSE: 5.05). Against the M/I values, BMFR also showed better goodness-of-fit than did FMR. In comparing correlation coefficients, the BMFR absolute B value was significantly larger than that of FMR (P = 0.027).

Conclusions

BMFR is more useful than FMR in quantifying IR in patients with T2DM because the correlation between BMFR and the insulin sensitivity index M/I is significantly greater than that between FMR and M/I.

Distribution of dietary protein intake in daily meals influences skeletal muscle hypertrophy via the muscle clock

The meal distribution of proteins throughout the day is usually skewed. However, its physiological implications and the effects of better protein distribution on muscle volume are largely unknown. Here, using the two-meals-per-day feeding model, we find that protein intake at the early active phase promotes overloading-induced muscle hypertrophy, in a manner dependent on the local muscle clock. Mice fed branched-chain amino acid (BCAA)-supplemented diets at the early active phase demonstrate skeletal muscle hypertrophy. However, distribution-dependent effects are not observed in ClockΔ19 or muscle-specific Bmal1 knockout mice. Additionally, we examined the relationship between the distribution of proteins in meals and muscle functions, such as skeletal muscle index and grip strength in humans. Higher muscle functions were observed in subjects who ingested dietary proteins mainly at breakfast than at dinner. These data suggest that protein intake at breakfast may be better for the maintenance of skeletal muscle mass.

Higher extracellular water to total body water ratio was associated with chronic kidney disease progression in type 2 diabetes

AIM

We studied the association between extracellular volume status and chronic kidney disease (CKD) progression; and the role of extracellular volume excess as a potential mediator in the relationship between matrix metalloproteinases (MMP)-2 and CKD progression in Type 2 diabetes mellitus (T2DM).

METHODS

We conducted a prospective cohort study of 1079 T2DM patients. Bioelectrical impedance analysis (BIA) was performed to assess body fluid status.

RESULTS

After up to 8.6 years of follow-up, 471 (43.7%) patients experienced CKD progression. In the fully adjusted model, extracellular water (ECW)/ total body water (TBW)ratios 0.39-0.40 and > 0.40 were associated with 45% and 78% higher risk of CKD progression respectively. Patients with an increase in ECW/TBW ratio had 40% higher risk of CKD progression compared to those with no change or reduction of ECW/TBW ratio. Higher ECW/TBW ratio accounted for 17.4% of the relationship between MMP-2 and CKD progression in T2DM (p = 0.026).

CONCLUSIONS

Extracellular volume excess was independently associated with CKD progression in T2DM. Higher ECW/TBW ratio mediated the positive association between MMP-2 and CKD progression. Further studies are needed to elucidate the role of extracellular volume excess in deterioration of renal function.

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.

Molecular and physical technologies for monitoring fluid and electrolyte imbalance: A focus on cancer population

Several clinical examinations have shown the essential impact of monitoring (de)hydration (fluid and electrolyte imbalance) in cancer patients. There are multiple risk factors associated with (de)hydration, including aging, excessive or lack of fluid consumption in sports, alcohol consumption, hot weather, diabetes insipidus, vomiting, diarrhea, cancer, radiation, chemotherapy, and use of diuretics. Fluid and electrolyte imbalance mainly involves alterations in the levels of sodium, potassium, calcium, and magnesium in extracellular fluids. Hyponatremia is a common condition among individuals with cancer (62% of cases), along with hypokalemia (40%), hypophosphatemia (32%), hypomagnesemia (17%), hypocalcemia (12%), and hypernatremia (1-5%). Lack of hydration and monitoring of hydration status can lead to severe complications, such as nausea/vomiting, diarrhea, fatigue, seizures, cell swelling or shrinking, kidney failure, shock, coma, and even death. This article aims to review the current (de)hydration (fluid and electrolyte imbalance) monitoring technologies focusing on cancer. First, we discuss the physiological and pathophysiological implications of fluid and electrolyte imbalance in cancer patients. Second, we explore the different molecular and physical monitoring methods used to measure fluid and electrolyte imbalance and the measurement challenges in diverse populations. Hydration status is assessed in various indices; plasma, sweat, tear, saliva, urine, body mass, interstitial fluid, and skin-integration techniques have been extensively investigated. No unified (de)hydration (fluid and electrolyte imbalance) monitoring technology exists for different populations (including sports, elderly, children, and cancer). Establishing novel methods and technologies to facilitate and unify measurements of hydration status represents an excellent opportunity to develop impactful new approaches for patient care.

An Efficient Multiple Kernel Support Vector Regression Model for Assessing Dry Weight of Hemodialysis Patients

Background:

Dry Weight (DW) is the lowest weight after dialysis, and patients with lower weight usually have symptoms of hypotension and shock. Several clinical-based approaches have been presented to assess the dry weight of hemodialysis patients. However, these traditional methods all depend on special instruments and professional technicians.

Objective:

In order to avoid this limitation, we need to find a machine-independent way to assess dry weight, therefore we collected some clinical influencing characteristic data and constructed a Machine Learning-based (ML) model to predict the dry weight of hemodialysis patients.

Methods::

In this paper, 476 hemodialysis patients' demographic data, anthropometric measurements, and Bioimpedance spectroscopy (BIS) were collected. Among them, these patients' age, sex, Body Mass Index (BMI), Blood Pressure (BP) and Heart Rate (HR) and Years of Dialysis (YD) were closely related to their dry weight. All these relevant data were used to enter the regression equation. Multiple Kernel Support Vector Regression-based on Maximizes the Average Similarity (MKSVRMAS) model was proposed to predict the dry weight of hemodialysis patients.

Result:

The experimental results show that dry weight is positively correlated with BMI and HR. And age, sex, systolic blood pressure, diastolic blood pressure and hemodialysis time are negatively correlated with dry weight. Moreover, the Root Mean Square Error (RMSE) of our model was 1.3817.

Conclusion:

Our proposed model could serve as a viable alternative for dry weight estimation of hemodialysis patients, thus providing a new way for clinical practice. Our proposed model could serve as a viable alternative of dry weight estimation for hemodialysis patients, thus providing a new way for the clinic.

A New Preoperative Risk Score for Predicting Postoperative Complications in Elderly Patients Undergoing Hepatectomy

BACKGROUND

Postoperative complications are not rare in the elderly population after hepatectomy. However, predicting postoperative risk in elderly patients undergoing hepatectomy is not easy. We aimed to develop a new preoperative evaluation method to predict postoperative complications in patients above 65 years of age using biological impedance analysis (BIA).

METHODS

Clinical data of 59 consecutive patients (aged 65 years or older) who underwent hepatectomy at our institution between 2017 and 2020 were retrospectively analyzed. Risk factors for postoperative complications (Clavien-Dindo ≥ III) were evaluated using multivariate regression analysis. Additionally, a new preoperative risk score was developed for predicting postoperative complications.

RESULTS

Fifteen patients (25.4%) had postoperative complications, with biliary fistula being the most common complication. Abnormal skeletal muscle mass index from BIA and type of surgical procedure were found to be independent risk factors in the multivariate analysis. These two variables and preoperative serum albumin levels were used for developing the risk score. The postoperative complication rate was 0.0% with a risk score of ≤ 1 and 57.1% with a risk score of ≥ 4. The area under the receiver operating characteristic curve of the risk score was 0.810 (p = 0.001), which was better than that of other known surgical risk indexes.

CONCLUSION

Decreased skeletal muscle and the type of surgical procedure for hepatectomy were independent risk factors for postoperative complications after elective hepatectomy in elderly patients. The new preoperative risk score is simple, easy to perform, and will help in the detection of high-risk elderly patients undergoing elective hepatectomy.

Assessing Dry Weight of Hemodialysis Patients via Sparse Laplacian Regularized RVFL Neural Network with L2,1-Norm

Dry weight is the normal weight of hemodialysis patients after hemodialysis. If the amount of water in diabetes is too much (during hemodialysis), the patient will experience hypotension and shock symptoms. Therefore, the correct assessment of the patient's dry weight is clinically important. These methods all rely on professional instruments and technicians, which are time-consuming and labor-intensive. To avoid this limitation, we hope to use machine learning methods on patients. This study collected demographic and anthropometric data of 476 hemodialysis patients, including age, gender, blood pressure (BP), body mass index (BMI), years of dialysis (YD), and heart rate (HR). We propose a Sparse Laplacian regularized Random Vector Functional Link (SLapRVFL) neural network model on the basis of predecessors. When we evaluate the prediction performance of the model, we fully compare SLapRVFL with the Body Composition Monitor (BCM) instrument and other models. The Root Mean Square Error (RMSE) of SLapRVFL is 1.3136, which is better than other methods. The SLapRVFL neural network model could be a viable alternative of dry weight assessment.

Time Course of Leg Edema after Endovenous Radiofrequency Ablation for Saphenous Varicose Veins

BACKGROUND

The objectives of the study were to quantitatively evaluate leg edema in patients undergoing endovenous radiofrequency ablation (RFA) for saphenous varicose veins using bioelectrical impedance analysis (BIA) and to elucidate the time course of leg edema after RFA.

METHODS

The data of 87 patients with 128 limbs undergoing RFA for saphenous varicose veins in Eniwa Midorino Clinic from April 2018 to November 2019 were retrospectively analyzed. Saphenous vein reflux was evaluated by duplex scan. Extracellular water/total body water ratio (ECW/TBW) of the leg was measured by BIA. Moderate to severe leg edema (ECW/TBW ≥ 0.400) was defined as significant leg edema. Venous reflux was evaluated as a venous filling index (VFI) using air plethysmography.

RESULTS

BIA revealed that 26 legs (20.3%) had significant edema and 102 legs (79.7%) did not before RFA. The proportion of patients with significant leg edema increased significantly from preoperative to 1 week after RFA (P < 0.05) and decreased 1 month after RFA (P < 0.01). The ECW/TBW increased significantly from preoperative (0.393 ± 0.008) to 1 week after RFA (0.394 ± 0.008, P < 0.05), whereas it decreased significantly before or 1 week to 1 month after RFA (0.391 ± 0.008, P < 0.05). There was a significant, moderate correlation between the decrease of the VFI and that of ECW/TBW (r = 0.34, P < 0.001).

CONCLUSIONS

This is the first study to quantitatively elucidate the time course of leg edema after RFA. Leg edema worsens one week after RFA, but it is improved one month after RFA, compared with that preoperatively.

Characteristics of nephropathy in severely obese Japanese patients complicated with type 2 diabetes mellitus: a cross-sectional cohort study

PURPOSE

We aimed to investigate the characteristics of kidney disease in severely obese Japanese patients with type 2 diabetes mellitus (T2DM).

METHODS

This was a cross-sectional study of severely obese patients (body mass index ≥35 kg/m²) with T2DM treated at Jinnouchi Hospital, Kumamoto, Japan.

RESULTS

A total of 3128 T2DM patients visited the hospital during the survey period, of whom 55 patients (1.7%) were severely obese and 50 patients were enrolled. In terms of diabetic nephropathy (DN), twenty-five patients were stage 1 (non-DN, 50.0%), sixteen were stage 2 (32.0%), five were stage 3 (10.0%), and four were stage 4 (8.0%). There were significant differences in the presence of urinary occult blood (P = 0.01) and history of cardiovascular disease (CVD) (P = 0.04) between patients with DN (stages 2-4) and those without DN (stage 1). The presence of urinary occult blood (odds ratio [OR], 4.96; 95% confidence interval, 1.32-18.6; P = 0.02) was significantly associated with the presence of DN according to multivariate logistic regression analysis with forced inclusion of age, sex, and CVD history.

CONCLUSIONS

Urinary occult blood may be a significant independent factor associated with the presence of nephropathy in severely obese Japanese patients with T2DM. The presence of urinary occult blood could thus be an important pathogenic factor in obesity-related nephropathy in patients with T2DM.

Capacitive-Coupling Impedance Spectroscopy Using a Non-Sinusoidal Oscillator and Discrete-Time Fourier Transform: An Introductory Study

In this study, we propose a new short-time impedance spectroscopy method with the following three features: (1) A frequency spectrum of complex impedance for the measured object can be obtained even when the measuring electrodes are capacitively coupled with the object and the precise capacitance of the coupling is unknown; (2) the spectrum can be obtained from only one cycle of the non-sinusoidal oscillation waveform without sweeping the oscillation frequency; and (3) a front-end measuring circuit can be built, simply and cheaply, without the need for a digital-to-analog (D-A) converter to synthesize elaborate waveforms comprising multiple frequencies. We built the measurement circuit using the proposed method and then measured the complex impedance spectra of 18 resistive elements connected in series with one of three respective capacitive couplings. With this method, each element's resistance and each coupling's capacitance were estimated independently and compared with their nominal values. When the coupling capacitance was set to 10 nF or 1.0 nF, estimated errors for the resistive elements in the range of 2.0-10.0 kΩ were less than 5%.

Validity of calf circumference for estimating skeletal muscle mass for Asian patients after stroke

OBJECTIVES

The aims of this study was to determine the optimal cutoff values of non-paretic calf circumference (CC) that are indicative of low skeletal muscle mass and examine the association between a low CC and rehabilitation outcomes.

METHODS

This was a retrospective cohort study that included 628 patients in convalescent rehabilitation wards in Japan. Patients in post-stroke rehabilitation who were ≥20 y of age were included. We examined the agreement between CC on the non-paretic side and a low skeletal muscle mass index (SMI) measured by bioelectrical impedance analysis. We also confirmed the correlation between sarcopenia defined by CC and handgrip strength, and sarcopenia according to Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Functional Independent Measure (FIM) at discharge and discharge to home outcomes were compared between patients with a high CC and those with a low CC.

RESULTS

Of the 628 patients included in the study, 408 (170 women; mean age, 72 y) were analyzed. The optimal cutoff values of CC were 33 cm for men (sensitivity and specificity, 0.798 and 0.840, respectively) and 32 cm for women (0.847 and 0.818, respectively). The sensitivity and specificity of CC-based sarcopenia against the AWGS criteria were 0.752 and 1.000 for men and 0.800 and 1.000 for women, respectively. Patients with a low CC had a significantly lower FIM and proportion of home discharge than those with a high CC.

CONCLUSIONS

The optimal cutoff values of non-paretic CC for a low SMI were 33 cm for male and 32 cm for female Asian stroke rehabilitation patients. Sarcopenia can be defined using CC instead of SMI.

Comparison between bioelectrical impedance spectroscopy measurements and water volume displacement of ankle oedema variations during the course of a day

OBJECTIVE

The purpose of this study was to find relationships between variations in bioelectrical impedance spectroscopy (BIS) measurements and those obtained by water displacement (WD) and calf (C) and ankle (A) perimetry on legs of patients with venous insufficiency and lower limb oedema, some with positive pitting test (PPT), others with negative pitting test (NPT).

APPROACH

Twenty-nine (29) female subjects were clinically examined prior to inclusion in the trial. Measurements were taken once in the morning and then 6 h later, using perimetry, WD, and then BIS; subjects were standing. Leg volume was assessed using two WD volumeters, one 'Tall' (TWD) and one 'Short' (SWD). BIS was performed using a SFB7 impedance meter device (Impedimed^®).

MAIN RESULTS

Forty-three (43) legs with oedema were included. The results showed that 61% of the TWD variations variance was explained by SWD variations; less than 30% of the TWD variations variance was explained using BIS or perimetry alone, and 45% at best when used in combination. R₀, related to extracellular water, was the key BIS parameter. For NPT subpopulation (32 legs), the composite parameter (C² - A²)/R₀ explained more than 60% of the TWD variations variance. For PPT subpopulation (11 legs), small or statistically non-significant variance explanations were found.

SIGNIFICANCE

Combination of anthropometric and BIS parameters gave a better forecast of WD results than using only one or other. A novel composite parameter, (C² - A²)/R₀, better predicted TWD changes than other parameters hitherto used in literature, with improved estimates for the NPT subpopulation. Study n°ANSM 2017-A01063-50.

Differences in pharmacological property between combined therapy of the vasopressin V2-receptor antagonist tolvaptan plus furosemide and monotherapy of furosemide in patients with hospitalized heart failure

BACKGROUND

Tolvaptan has been shown to improve congestion in heart failure patients. The purpose of this study was to evaluate the pharmacology and clinical efficacy of combined tolvaptan and furosemide therapy.

METHODS

This study included 40 patients with systemic volume overload who were hospitalized for heart failure. Patients who showed no improvement in the condition after receiving 20 mg intravenous furosemide were included and were randomly selected to receive tolvaptan as an add-on to furosemide or to receive an increased dose of furosemide. We evaluated the bioelectrical impedance analyzer parameters, the parameters of the inferior vena cava using echocardiography, vital signs, body weight, urine output, and laboratory data for 5 days.

RESULTS

In the changes from baseline between intracellular water volume (ICW) and extracellular water volume (ECW) after additional use of tolvaptan or furosemide from Day 1 to Day 5, there were no significant differences observed between ICW and ECW over 5 days in the tolvaptan + furosemide group, although differences were found in the furosemide group from Day 2 onward. Changes in the respiratory collapse of inferior vena cava increased significantly, and systolic blood pressure decreased significantly only in the furosemide group.

CONCLUSIONS

The present study clearly demonstrates that combined therapy with tolvaptan and furosemide removed excess ICW and ECW to an equal extent, while furosemide alone primarily removed ECW, including intravascular water.

Daily salt intake is associated with leg edema and nocturnal urinary volume in elderly men

AIMS

There is accumulating evidence that excessive salt intake contributes to nocturnal polyuria. We aimed to investigate the relationship between salt intake, leg edema, and nocturnal urine volume (NUV) to assess the etiology of nocturnal polyuria.

METHODS

A total of 56 men aged ≥60 years who were hospitalized for benign prostatic hyperplasia or with suspected prostatic cancer were enrolled. Urine frequency-volume charts of the patients were maintained, and they underwent bioelectrical impedance analysis twice daily (at 5:00 pm and 6:00 am) and examination of blood (brain natriuretic peptide levels) and urine (sodium and creatinine levels and osmotic pressure) samples once daily (at 6:00 am). Free-water clearance, solute clearance, and sodium clearance at night were measured, and daily salt intake was estimated.

RESULTS

The data of 52 patients were analyzed. Daily salt intake positively correlated with leg edema at 5:00 pm, differences in leg extracellular fluid levels between 5:00 pm and 6:00 am, and NUV, but not with diurnal urine volume. Partial correlation coefficients showed that salt intake was a factor of the correlation between NUV and change in extracellular volume in the legs between 5:00 pm and 6:00 am. A multivariate logistic model showed that sleep duration and sodium clearance were independent predictive factors for nocturnal polyuria.

CONCLUSIONS

Sodium intake correlates with diurnal leg edema and NUV in elderly men. These results provide evidence supporting sodium restriction as an effective treatment for nocturnal polyuria.

Comparison of Bioelectrical Impedance Analysis and Dual Energy X-ray Absorptiometry for Total and Segmental Bone Mineral Content with a Three-Compartment Model

Modern bioelectrical impedance analysis (BIA) provides a wide range of body composition estimates such as fat mass (FM), lean body mass (LBM), and body water, using specific algorithms. Assuming that the fat free mass (FFM) and LBM can be accurately estimated by the 8-electrode BIA analyzer (BIA_8MF; InBody230, Biospace), the bone mineral content (BMC) may be calculated by subtracting the LBM from the FFM estimates based on the three-compartment (3C) model. In this cross-sectional study, 239 healthy Taiwanese adults (106 male and 133 female) aged 20-45 years were recruited for BIA and dual-energy X-ray absorptiometry (DXA) measurements of the whole body and body segments, with DXA as the reference. The results showed a high correlation between BIA_8MF and DXA in estimating total and segmental LBM, FM and percentage body fat (r = 0.909-0.986, 0.757-0.964, and 0.837-0.936, respectively). For BMC estimates, moderate to high correlations (r = 0.425-0.829) between the two methods were noted. The percentage errors and pure errors for BMC estimates between the methods ranged from 33.9% to 93.0% and from 0.159 kg to 0.969 kg, respectively. This study validated that BIA_8MF can accurately assesses LBM, FM and body fat percentage (BF%). However, the estimation of segmental BMC based on the difference between FFM and LBM in body segments may not be reliable by BIA_8MF.

Measurement of Fluid Shift in Capd Patients Using Segmental Bioelectrical Impedance Analysis

Objective

To determine, using segmental bioelectrical impedance analysis (BIA), the characteristics of fluid shift of each body segment in continuous ambulatory peritoneal dialysis (CAPD) patients during and after peritoneal dialysis (PD) solution exchange.

Design

Observational study with repeated measurements of bioelectrical impedance, which is inversely related to tissue fluid content.

Patients

Thirteen clinically stable CAPD patients.

Methods

Bioelectrical impedance was measured at frequencies of 5, 50, 250, and 500 kHz in each body segment four times: (1) before and (2) after drainage of dialysate, and (3) at 1 hour and (4) at 2 hours after exchange of new 1.5% dextrose PD solution.

Results

Impedance of both arms was significantly increased at 1 hour post exchange at all frequencies. In the trunk, impedance at all frequencies increased significantly after drainage, decreased significantly at 1 hour post exchange, and then increased again for the next hour without significance. Impedance of both legs showed a decreasing tendency at all frequencies during and after exchange. Net calculated water volume changes between the time before drainage and 2 hours post exchange were –0.5 L in the trunk, –0.25 L in both arms, +0.47 L in both legs, –0.28 L in total. The change in body weight between the time before drainage and 2 hours post exchange was –0.21 kg, on average, and significantly correlated with total net calculated water volume change ( p = 0.009).

Conclusions

Each body segment of the CAPD patient has its own characteristic pattern of fluid shift in response to PD solution exchange or dwell. Segmental BIA may be a useful tool for understanding the physiological changes in fluid shift in CAPD patients.

Body muscle-to-fat ratio gender-specific cut-off values for impaired insulin sensitivity in patients with treatment-naïve type 2 diabetes mellitus

PURPOSE

We previously reported that the body muscle-to-fat ratio (BMFR), measured using bioelectrical impedance, significantly correlated with whole-body insulin sensitivity. We examined BMFR gender-specific cut-off values for impaired insulin sensitivity in treatment-naïve type 2 diabetes mellitus (T2DM) patients.

METHODS

Subjects included 101 untreated T2DM patients (male, 66; female, 35). We performed a hyperinsulinemic-euglycemic clamp examination to measure the steady-state glucose infusion rate (M value) as an indicator of whole-body insulin resistance. We defined the M value divided by the steady-state serum insulin value as the M/I value. We defined the existence of insulin resistance using an M/I ratio <9.0. The optimal cut-off value for BMFR was calculated by receiver operating characteristics (ROC) analysis.

RESULTS

The cut-off value of the BMFR for insulin resistance was 2.75 (area under the curve [AUC] = 0.83, sensitivity 75%, and specificity 76%, P < 0.001) for males and 1.65 (AUC = 0.87, sensitivity 84%, and specificity 81%, P < 0.001) for females. Simple linear regression analysis showed that BMFR was significantly correlated with the M/I value in both genders (males, B = 0.77, P< 0.01; females, B = 0.83, P< 0.01).

CONCLUSIONS

BMFR cut-off values for impaired insulin sensitivity in treatment-naïve T2DM patients were 2.75 for males and 1.65 for females.

Empagliflozin's Ameliorating Effect on Plasma Triglycerides: Association with Endothelial Function Recovery in Diabetic Patients with Coronary Artery Disease

Aim: So far, the mechanisms behind the cardiovascular benefits of sodium/glucose cotransporter 2 (SGLT2) inhibitors have not been fully clarified.

Methods: In order to evaluate the effects of SGLT2 inhibitors on systemic hemodynamics, glucose metabolism, lipid profile, and endothelial function, 50 diabetic patients with established coronary artery disease (CAD) were included in this analysis and were given empagliflozin 10 mg/d. Cookie meal testing (carbohydrates: 75 g, fats: 28.5 g), endothelial function testing using flow-mediated dilatation (FMD), and body composition evaluation were performed before and after six months of treatment. Changes in %FMD between the treatment periods and its association with metabolic biomarkers were evaluated.

Results: After six months of treatment, the body weight and body fat percentage decreased significantly, while the body muscle percentage increased significantly. The hemoglobin A1c level and fasting and postprandial plasma glucose levels were significantly decreased with treatment. Postprandial insulin secretion was also significantly suppressed and the insulin resistance index was significantly decreased. Furthermore, the fasting and postprandial triglyceride (TG) levels decreased significantly, while total ketone bodies increased significantly after the six-month treatment. While the plasma brain natriuretic peptide level was not changed, the C-reactive protein level was decreased and FMD was significantly improved after the six-month treatment. Multiple regression analysis showed that the strongest predictive factor of FMD improvement is change in the plasma TG levels.

Conclusion: SGLT2 inhibitors improve multiple metabolic parameters. Of these, a reduction in plasma TGs was strongly associated with endothelial function recovery in diabetic patients with CAD, and this reduction may be related to the cardiovascular benefits of SGLT2 inhibitors.

Robust Longitudinal Ankle Edema Assessment Using Wearable Bioimpedance Spectroscopy

OBJECTIVE

We present a robust methodology for tracking ankle edema longitudinally based on bioimpedance spectroscopy (BIS).

METHODS

We designed a miniaturized BIS measurement system and employed a novel calibration method that enables accurate, high-resolution measurements with substantially lower power consumption than conventional approaches. Using this state-of-the-art wearable BIS measurement system, we developed a differential measurement technique for robust assessment of ankle edema. This technique addresses many of the major challenges in longitudinal BIS-based edema assessment, including day-to-day variability in electrode placement, positional/postural variability, and intersubject variability.

RESULTS

We first evaluated the hardware in bench-top testing, and determined the error of the bioimpedance measurements to be 0.4 Ω for the real components and 0.54 Ω for the imaginary components with a resolution of 0.2 Ω. We then validated the hardware and differential measurement technique in: 1) an ex vivo, fresh-frozen, cadaveric limb model, and 2) a cohort of 11 human subjects for proof of concept (eight healthy controls and five subjects with recently acquired acute unilateral ankle injury).

CONCLUSION

The hardware design, with novel calibration methodology, and differential measurement technique can potentially enable long-term quantification of ankle edema throughout the course of rehabilitation following acute ankle injuries.

SIGNIFICANCE

This could lead to better-informed decision making regarding readiness to return to activities and/or tailoring of rehabilitation activities to an individual's changing needs.

Sodium Selenite Alleviates Breast Cancer-Related Lymphedema Independent of Antioxidant Defense System

Long-term surveillance is necessary to identify patients at risk of developing secondary lymphedema after breast cancer surgery. We assessed how sodium selenite supplementation would affect breast cancer-related lymphedema (BCRL) symptoms and parameters in association with antioxidant effects. A randomized, double-blind, controlled trial was conducted on 26 participants with clinical stage II to III BCRL. The control group (CTRL, n = 12) and selenium group (SE, n = 14) underwent five sessions of 0.9% saline and 500 μg sodium selenite (Selenase^®) IV injections, respectively, within 2 weeks. All patients were educated on recommended behavior and self-administered manual lymphatic drainage. Clinical diagnosis on lymphedema by physicians, bioimpedance data, blood levels of oxidative markers, including glutathione (GSH), glutathione disulfide (GSSG), malondialdehyde (MDA), glutathione peroxidase activity (GSH-Px), and serum oxygen radical absorbance capacity (ORAC) levels, were investigated at timelines defined as baseline, 2-week, and follow-up. Sodium selenite increased whole blood selenium concentration in the SE group. Compared to the baseline, at 2 weeks, 75.0% of participants in clinical stage showed improvement, while there was no change in the CTRL group. At follow-up, 83.3% and 10.0% of the SE and CTRL, respectively, showed stage changes from III to II (p = 0.002). Extracellular water (ECW) ratios were significantly reduced at 2 weeks and follow-up, only in the SE group. Blood GSH, GSSG, GSH/GSSG ratio, MDA, and ORAC levels did not change by selenium supplementation. Sodium selenite improved diagnostic stages of BCRL along with ECW ratios, although the beneficial effect might not be related to its antioxidant activity. Selenite’s effect on lymphedema may be associated with non-antioxidant properties, such as anti-inflammation and immune function. Further mechanistic research using a larger population is needed.

Reference values of bioelectrical impedance analysis for detecting breast cancer-related lymphedema

Secondary lymphedema is a chronic debilitating lifelong complication and early diagnosis is crucial. The Inbody 720, which is widely used, has no universal index of diagnostic criteria for test results. We aim to determine the normal range, cutoff values, and mean + standard deviation values of extracellular fluid (ECF) and the single frequency bioimpedance (SFBIA) ratios for the diagnosis of lymphedema and suggest the usefulness of these values for detecting lymphedema.Seventy patients with unilateral breast cancer-related lymphedema and 643 healthy subjects were enrolled. All patients with breast cancer underwent surgeries with dissection of lymph nodes. We analyzed the ECF volume, SFBIA at 1- and 5-kHz frequencies using Inbody 720.There were significant differences between patients with BCRL and healthy controls. The optimal cutoff values for ECF ratios were 1.010 for both the dominant and non-dominant arms. At 1 kHz, the cutoff values of SFBIA were 1.050 and 1.046, and at 5 kHz, those were 1.070 and 1.030 for the dominant and non-dominant affected arms, respectively. The mean + 2SD values for ECF ratio were 1.018 and 1.020 and at 1 kHz, the mean + 2SD values of SFBIA were 1.144 and 1.0135 and at 5 kHz, the cutoff values of SFBIA were 1.141 and 1.124 for the dominant and non-dominant affected arms, respectively. The mean + 3SD values for ECF ratio were 1.026 and 1.030 and at 1 kHz, the mean + 3SD values of SFBIA were 1.206 and 1.203 and at 5 kHz, those were 1.201 and 1.187 for the arms, respectively. The cutoff, mean + 2SD, and mean + 3SD values were applied to 70 patients with unilateral BCRL. When the cutoff values were applied, a higher proportion of BCRL patients were included.When these figures were applied to the patient group, the cutoff values included a higher proportion of patients with lymphedema. Further studies are needed to investigate whether bioimpedance analysis can accurately predict the development of lymphedema.

Clinical usefulness of the body muscle-to-fat ratio for screening obstructive sleep apnea syndrome in patients with inadequately controlled type 2 diabetes mellitus

AIMS

To investigate whether body composition measures can be used for screening obstructive sleep apnea syndrome (OSAS) in patients with type 2 diabetes mellitus (T2DM) suspected of having OSAS.

METHODS

Subjects were 186 hospital inpatients with inadequately controlled T2DM. We measured the respiratory disturbance index (RDI) as an indicator of OSAS using a sheet-type breath detection monitor, defining OSAS as an RDI ≥ 19 events/hour. Elementary body composition was measured by bioelectrical impedance analysis using InBody770.

RESULTS

Simple logistic regression analysis identified body weight, body mass index (BMI), waist circumference, total body fat mass, body fat percentage, and body muscle-to-fat ratio (BMFR) as significantly associated with OSAS. The Nagelkerke R² test showed that the BMFR was the most suitable measure for screening OSAS. Multivariate logistic regression analysis demonstrated that BMFR was significantly and independently associated with OSAS. In receiver operating characteristic curve analysis, the area under the BMFR curve was 0.70 (P < 0.001), indicating that BMFR was significantly predictive of OSAS. Furthermore, BMFR was the most suitable measure for screening OSAS in a sub-group analysis of non-obese patients with relatively low BMI (<27.5 kg/m²).

CONCLUSIONS

In patients with T2DM, the BMFR is useful for screening OSAS in daily clinical practice.