Elsevier

Medical Engineering & Physics

Volume 84, October 2020, Pages 10-15
Medical Engineering & Physics

Configuration of bioelectrical impedance measurements affects results for phase angle

https://doi.org/10.1016/j.medengphy.2020.07.021Get rights and content
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open access

Highlights

  • Phase angle by bioelectrical impedance analyses depends on measurement configuration.

  • Phase angle is higher in supine than in standing measurements.

  • Electrode placement and body side (right vs. left) also affect phase angle.

  • The BIA devices seca mBCA 515 and mBCA 525 were used for comparison.

Abstract

Objective

Phase angle (PhA) obtained by bioelectrical impedance analysis is a well-established predictor of malnutrition that reflects the amount and quality of soft tissue. However, PhA results may depend on configurations of the measurement that differ between devices. The aim was to analyze differences between devices for supine and standing measurements.

Approach

In a cross-sectional study, differences in PhA were analyzed comparing supine vs. standing positions, metal vs. adhesive electrodes and the right vs. left side of the body in 302 multi-ethnic adults (18–65y) and 1298 Mexican children and adolescents (4–20y).

Main results

PhA was higher in supine than in standing position (from 0.71°±0.22° in children to 0.97°±0.25° in adults; all p < 0.001) with approximately fifty percent of observed differences explained by electrode placement. PhA differences increased with increasing PhA (r = 0.419) and decreased with age (r = −0.346) in adults, but increased with PhA (r = 0.677), age (r = 0.752) and height (r = 0.737) in children (all p <0.001). In adults, PhA was higher on the right side of the body (standing 0.18°±0.17°; supine 0.36°±0.33°; p <0.001).

Significance

Phase angle results are influenced by posture and electrode placement. Measurement configuration must be considered when phase angle values are compared between different devices or with literature values.

Keywords

Phase angle
Bioelectrical impedance analysis
Position
Standing
Supine
Electrode placement

Abbreviations

BIA
bioelectrical impedance analysis
PhA
phase angle

Cited by (0)

Trial Registrations: ClinicalTrials.gov NCT01368640, NCT03779932, NCT01471938