Differences in bioimpedance-derived fluid status between two versions of the Body Composition Monitor

Sebastian Mussnig; Michael Schmiedecker; Maximilian Waller; Janosch Niknam; Christopher Paschen; Daniel Schneditz; Manfred Hecking; Simon Krenn

doi:10.1016/j.nut.2023.112131

Differences in bioimpedance-derived fluid status between two versions of the Body Composition Monitor

Nutrition. 2023 Oct:114:112131. doi: 10.1016/j.nut.2023.112131. Epub 2023 Jun 14.

Authors

Sebastian Mussnig¹, Michael Schmiedecker¹, Maximilian Waller², Janosch Niknam¹, Christopher Paschen¹, Daniel Schneditz³, Manfred Hecking⁴, Simon Krenn⁵

Affiliations

¹ Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
² Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria; Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria.
³ Division of Physiology and Pathophysiology, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz, Graz, Austria.
⁴ Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria; Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria. Electronic address: manfred.hecking@meduniwien.ac.at.
⁵ Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria; Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria; Medical Signal Analysis, Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria.

PMID: 37467529
DOI: 10.1016/j.nut.2023.112131

Abstract

Objectives: The Body Composition Monitor (BCM) (Fresenius Medical Care) measures body impedances in alternating currents to subsequently calculate fat and lean tissue mass, fluid compartments, and overhydration (OH). The aim of this study was to investigate differences between two versions of the BCM (an older version, 3.2.5, and a newer version, 3.3.3).

Methods: Between September 2021 and December 2021, 28 hemodialysis patients were included to undergo BCM measurements before each of 14 consecutive dialysis sessions with versions 3.2.5 and 3.3.3 devices. Measurements were performed according to instructions provided by the manufacturer. Differences between BCM devices were tested for statistical significance using paired Wilcoxon tests, neglecting clustering.

Results: A total of 288 measurement pairs of 27 patients were left after exclusion of 43 flawed data points. The mean difference in OH between both BCM devices was 0.548 L (higher for version 3.2.5). Analysis of impedance data revealed differences in the high-frequency spectrum, quantifiable by the intracellular resistance, R_i (median R_{i version 3.2.5} = 1750.3 Ω; R_{i version 3.3.3} = 1612.45 Ω; P < 0.001), and the time delay, T_d (median T_{d version 3.2.5} = 1.85 ns; T_{d version 3.3.3} = 8.88 nanoseconds; P < 0.001).

Conclusions: This study finds that results between the two versions of the BCM differed in a clinically meaningful fashion and that the newer version 3.3.3 device had a bias toward less OH. Circulating BCM devices should be checked for versions and only devices of the same version should be used for each patient to ensure better within-patient consistency.

Keywords: Bioimpedance; Body Composition Monitor; Chronic hemodialysis; Fluid status; Target weight.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Body Composition*
Body Fluid Compartments
Electric Impedance
Humans
Renal Dialysis*