An evaluation of phase angle, bioelectrical impedance vector analysis and impedance ratio for the assessment of disease status in children with nephrotic syndrome

Steven Brantlov,René Frydensbjerg Andersen,Lars Jødal,Leigh C Ward,Søren Rittig,Aksel Lange

doi:10.1186/s12882-019-1511-y

Steven Brantlov, René Frydensbjerg Andersen + Show 4 more

Open Access

https://doi.org/10.1186/s12882-019-1511-y

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Abstract

BackgroundOedema, characterized by accumulation of extracellular water (ECW), is one of the major clinical manifestations in children suffering from nephrotic syndrome (NS).The lack of a simple, inexpensive and harmless method for assessing ECW may be solved by the use of the bioelectrical impedance analysis (BIA) technique.The aims of this study were to examine whether phase angle (PA), bioelectrical impedance vector analysis (BIVA) and the impedance ratio (IR) reflect change in disease status in children with NS.MethodsEight children (age range: 2–10 years) with active NS (ANS group) were enrolled. In five of these (ANS* subgroup), impedance was also measured at remission (NSR group). Thirty-eight healthy children (age range: 2–10 years) were included as healthy controls (HC group). Whole-body impedance was measured with a bioimpedance spectroscopy device (Xitron 4200) with surface electrodes placed on the wrist and ankle.ResultsValues of PA, BIVA and IR were found to be significantly lower (p-value range < 0.001 to < 0.01) in the ANS patients compared to the HC and NSR groups. No significant differences were observed between the NSR and HC groups.ConclusionThe studied parameters can be used to assess change in disease status in NS patients. Data were consistent with NS being associated with expansion of ECW.

Highlights

Oedema, characterized by accumulation of extracellular water (ECW), is one of the major clinical manifestations in children suffering from nephrotic syndrome (NS)
Participant characteristics Comparison between all the participants enrolled in the study (Additional file 1: Table S1) showed no significant differences in any parameters between the NS and control participants and between the NS sub-groups
Phase Angle The absolute and relative mean differences of the phase angle (PA) values for the Active nephrotic syndrome (ANS) patients compared to the Healthy controls (HC) were − 2.3 degrees (− 43.4%) for PA50 and − 2.7 degrees (− 44.3%) for PAfc

Summary

Introduction

Oedema, characterized by accumulation of extracellular water (ECW), is one of the major clinical manifestations in children suffering from nephrotic syndrome (NS). The Dilution techniques using the tracers deuterated water (D2O, “heavy water”) and sodium bromide (NaBr) are the criterion techniques for determining total body water (TBW) and ECW volumes respectively These are, potentially invasive, expensive, time consuming, not possible to repeat at short intervals and require highly trained personnel to make the measurements [4], making them unsuitable for routine use in the clinic [5]. For these reasons, there is need for a simple, inexpensive and harmless method for routine assessment of disease status that can provide new and clinically useful. A possible approach that may prove to be of use is the bioelectrical impedance analysis (BIA) technique, which is characterized by being non-invasive, harmless, quick, simple, inexpensive, and portable and suitable for routine use [6]

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