Evaluation of different bioimpedance methods for assessing body composition in Asian non-dialysis chronic kidney disease patients

Abstract

Background Chronic kidney disease (CKD) is associated with fluid retention, which increases total body water (TBW) and leads to changes in intracellular water (ICW) and extracellular water (ECW). This complicates accurate assessments of body composition. Analysis of bioelectrical impedance may improve the accuracy of evaluation in CKD patients and multiple machines and technologies are available. We compared body composition by bioimpedance spectroscopy (BIS) against multi-frequency bioimpedance analysis (BIA) in a multi-ethnic Asian population of stable, non-dialysis CKD patients. Methods We recruited 98 stable CKD patients comprising 54.1% men and 70.4% Chinese, 9.2% Malay, 13.3% Indian, and 8.2% other ethnicities. Stability was defined as no variation in serum creatinine > 20% over three months. Patients underwent BIS analyses using a Fresenius body composition monitor, while BIA analyses employed a Bodystat Quadscan 4000. Results Mean TBW values by BIS and BIA were 33.6 ± 7.2 L and 38.3 ± 7.4 L; mean ECW values were 15.8 ± 3.2 L and 16.9 ± 2.7 L; and mean ICW values were 17.9 ± 4.3 L and 21.0 ± 4.9 L, respectively. Mean differences for TBW were 4.6 ± 1.9 L ( P < 0.001), for ECW they were 1.2 ± 0.5 L ( P < 0.001), and for ICW they were 3.2 ±1.8 L ( P < 0.001). BIA and BIS measurements were highly correlated: TBW r = 0.970, ECW r = 0.994, and ICW r = 0.926. Compared with BIA, BIS assessments of fluid overload appeared to be more associated with biochemical and clinical indicators. Conclusion Although both BIA and BIS can be used for body water assessment, clinicians should be aware of biases that exist between bioimpedance techniques. The values of body water assessments in our study were higher in BIA than in BIS. Ethnicity, sex, body mass index, and estimated glomerular filtration rate were associated with these biases.

Comparison of Body Composition Monitor and InBody 720 Bioimpedance Devices for Body Composition Estimation in Hemodialysis Patients and Healthy Controls

“…Our results show that MF-BIA provides statistically different results for ICW, ECW, TBW and fat mass measurements in healthy males and HD male patients, which is consistent with the results of Lee and colleagues (2019) [49]. On average, MF-BIA recorded up to 25% higher values for ICW, up to 10% higher values for TBW, up to 10% lower values for ECW and up to 20% lower for body fat.…”

“…On average, MF-BIA recorded up to 25% higher values for ICW, up to 10% higher values for TBW, up to 10% lower values for ECW and up to 20% lower for body fat. The reported differences are likely due to a different number of frequencies [49,50] or different equations and assumptions used [46]. In addition, MF-BIA has been shown to overestimate TBW in overweight and obese patients compared to other methods, and using MF-BIA to estimate fat mass was not the most reliable method [46].…”

“…Only a few studies were conducted comparing two different methods of body composition assessment, mostly BIS with conventional [41] or dual-energy X-ray absorptiometry [45,46], and only two comparing BIS and BIA [47,48]. However, few studies were performed on patients, and only one study compared BIS and MF-BIA methods in HD patients [49], but with different monitors. To the best of our knowledge, this is the first study to compare ICW, ECW, TBW and fat mass measured with InBody 720 and Fresenius BCM in healthy and HD male patients.…”

From MIA to FIFA: The vicious matrix of frailty, inflammation, fluid overload and atherosclerosis in peritoneal dialysis

“…However, there are limitations of bioimpedance measurements. Although tissue water content estimated by BIS correlated to the dilution scans, 100,101 there are considerable differences in agreement between different methods 102–104 . Most studies on bioimpedance used the 3‐compartment model, which is based on a fixed assumption on the hydration ratio of lean tissue mass and adipose tissue mass, 99 but this ratio may be altered by fluid shift from intra‐ to extracellular fluid compartment due to a loss of cell membrane integrity (so‐called ‘sick cell syndrome’) or by excretion of phosphate and potassium from the intracellular compartment 105,106 .…”

Comparison of Phase Angle Using Bioelectrical Impedance Analysis According to Device Type and Examination Posture

“…BIA is becoming popular as a body composition assessment tool for patients (1). It has been studied in the general population, patients with malignancy, sarcopenia, obesity, frailty, chronic kidney disease, or cardiovascular disease, as well as in patients in surgical care, and intensive care units (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). However, although BIA has always been a topic of discussion, several limitations have been noted, including the reliability of different algorithms, time of measurement, effect of eating or exercise prior to measurement, ethnicity, sex, and age (15)(16)(17)(18)(19)(20).…”