Future lines of research on phase angle: Strengths and limitations

Abstract

Bioelectrical impedance analysis (BIA) is the most widely used technique in body composition analysis. When we focus the use of phase sensitive BIA on its raw parameters Resistance (R), Reactance (Xc) and Phase Angle (PhA), we eliminate the bias of using predictive equations based on reference models. In particular PhA, have demonstrated their prognostic utility in multiple aspects of health and disease. In recent years, as a strong association between prognostic and diagnostic factors has been observed, scientific interest in the utility of PhA has increased. In the different fields of knowledge in biomedical research, there are different ways of assessing the impact of a scientific-technical aspect such as PhA. Single frequency with phase detection bioimpedance analysis (SF-BIA) using a 50 kHz single frequency device and tetrapolar wrist-ankle electrode placement is the most widely used bioimpedance approach for characterization of whole-body composition. However, the incorporation of vector representation of raw bioelectrical parameters and direct mathematical calculations without the need for regression equations for the analysis of body compartments has been one of the most important aspects for the development of research in this area. These results provide new evidence for the validity of phase-sensitive bioelectrical measurements as biomarkers of fluid and nutritional status. To enable the development of clinical research that provides consistent results, it is essential to establish appropriate standardization of PhA measurement techniques. Standardization of test protocols will facilitate the diagnosis and assessment of the risk associated with reduced PhA and the evaluation of changes in response to therapeutic interventions. In this paper, we describe and overview the value of PhA in biomedical research, technical and instrumental aspects of PhA research, analysis of Areas of clinical research (cancer patients, digestive and liver diseases, critical and surgical patients, Respiratory, infectious, and COVID-19, obesity and metabolic diseases, Heart and kidney failure, Malnutrition and sarcopenia), characterisation of the different research outcomes, Morphofunctional assessment in disease-related malnutrition and other metabolic disorders: validation of PhA with reference clinical practice techniques, strengths and limitations. Based on the detailed study of the measurement technique, some of the key issues to be considered in future PhA research. On the other hand, it is important to assess the clinical conditions and the phenotype of the patients, as well as to establish a disease-specific clinical profile. The appropriate selection of the most critical outcomes is another fundamental aspect of research.

Phase angle as an indicator of body composition and physical performance in handball players

“…Likewise, we observed a negative correlation between body fat % and PhA when evaluating both sexes. However, it is essential to recognize that PhA is influenced by various factors beyond body fat alone, such as hydration status, muscle mass, and overall health conditions [ 32 ]. Therefore, while phase angle may offer insights into body composition and health status, it should be interpreted alongside other clinical measures to provide a comprehensive assessment.…”

Bioelectrical impedance analysis—derived phase angle (PhA) in lung cancer patients: a systematic review

“…Timely analysis of patient’s nutritional status is essential, as it allows to avoid significant loss of cell mass and lean mass, but ensures a proper nutritional approach in order to avoid aggravation of the general condition of the patient. Moreover, to obtain an accurate clinical interpretation of PhA, simultaneous assessment of hydration and BCM status is required [ 58 ]. These informations could be derived from the analysis of vector length on the R/Xc plot using Bioelectrical Impedance Vectorial Analysis (BIVA) (a scatterplot that represents R in X-axis and Xc in Y-axis divided by height in meters).…”

Radiological assessment of skeletal muscle index and myosteatosis and their impact postoperative outcomes after liver transplantation

“…BIA is commonly used technique in body composition analysis in every day clinical practice. 50 Its key parameters are resistance, reactance and phase angle (PA). PA is found to be associated with outcomes in different diseases and has been found to be useful for monitoring fluid changes and response to interventions.…”

“…PA is found to be associated with outcomes in different diseases and has been found to be useful for monitoring fluid changes and response to interventions. 50 The main limitation is the complexity of the determinants that requires its adjustment to the individual phenotypic diagnosis of each patient. Results can be affected by altered water and electrolyte balance, fluid retention and diuretic therapy.…”

“…Results can be affected by altered water and electrolyte balance, fluid retention and diuretic therapy. 50 DXA allows for the quantification of three body compartments (bone mass, fat mass, and bone fat-free mass (or lean mass)) based upon the differential tissue attenuation of X-ray photons. 51 However, it can be affected by presence of ascites.…”