Phase Angle and Handgrip Strength as a Predictor of Disease-Related Malnutrition in Admitted Patients: 12-Month Mortality

Abstract

Background: Phase Angle (PhA) value measured by bioelectrical impedance analysis (BIA) could be considered a good marker of the patient’s cell mass and cellular damage. Various studies have shown that the value of PhA is associated with an increased nutritional risk in several pathologies. However, not many studies have focused on the use of PhA as a screening tool in admitted patients. The aim of this study is to evaluate the prognostic value of PhA to determine disease-related malnutrition (DRM) and the risk that this entails for mortality and length of stay (LOS). Methods: 570 patients admitted to the hospital for different causes were included in this retrospective observational study. Patients’ nutritional risk was assessed by screening tests such as the Malnutrition Universal Screening tool (MUST) and Subjective Global Assessment (SGA), in addition to non-invasive functional techniques, such as BIA and handgrip strength (HGS), 24−48 h after admission. After performing an SGA as the gold standard to assess malnutrition, PhA and SPhA values were used to determine DRM. Furthermore, both samples: malnutrition status (MS) and non-malnutrition status (NMS) were compared, with SphA-Malnutrition corresponding to a diagnosis of malnutrition. Statistical analysis of the sample was conducted with JAMOVI version 2.2.2. Results: Patients with MS had lower PhA and SPhA than patients with NMS (p < 0.001). The ROC curve analysis (AUC = 0.81) showed a cut-off point for MS for PhA = 5.4° (sensitivity 77.51% and specificity 74.07%) and AUC = 0.776 with a cut-off point for SPhA = −0.3 (sensitivity 81.74% and specificity 63.53%). Handgrip strength (HGS) was also observed to be a good predictor in hospitalized patients. Carrying out a comparative analysis between MS and NMS, length of stay (LOS) was 9.0 days in MS vs. 5.0 days in NMS patients (OR 1.07 (1.04−1.09, p < 0.001)). A low SPhA-malnutrition value (SPhA < −0.3) was significantly associated with a higher mortality hazards ratio (HR 7.87, 95% CI 2.56−24.24, p < 0.001). Conclusion: PhA, SPhA and HGS are shown to be good prognostic markers of DRM, LOS and mortality and could therefore be useful screening tools to complement the nutritional assessment of admitted patients.

Keywords: admitted patient; assessment tools; malnutrition; mortality; phase angle.

Figure A1

Flow chart.

Figure 1

Associations of PhA and HGS with malnutrition tools. Abbreviations: NMS (non–malnutrition status); MS (malnutrition status); OR (odds ratio).

Figure 2

ROC−curve analyses for variables to detect DRM in admitted patients. (a) Overall ROC–curve analysis for PhA, BCM, SPhA and HGS; (b) ROC−curve analysis for PhA by gender; (c) ROC−curve analysis for BCM by gender; (d) ROC−curve analysis for HGS by gender to detect DRM.

Figure 3

The distribution of impedance point vector of the admitted patients. Representing values of R/H and Xc/H in patients. (a) Green point, Survival patients (SP) and black point, non-survival patients (NSP). (b) Green point, Malnutrition status (MS) and black point, non-malnutrition status (NMS) using SPhA-malnutrition as a DRM diagnostic parameter. Bioelectrical values of malnutrition: survival patients (n = 484), non-survival (n = 86) and R: resistance (Ohm); Xc: reactance (Ohm); H: height (m); (R/H) and (Xc/H): R/H and Xc/H standardized for sex and age using bioelectrical Italian standards. The bioelectrical impedance vector distribution analysis shows a situation of inflammation and cellular injury associated with malnutrition. The lower right quadrant encompasses patients with decreased cell mass and hyperhydration, most of the deceased patients.

Figure 4

Kaplan–Meier survival curves of patients in groups with low or high SPhA-Malnutrition and HGS-Malnutrition. The table at the bottom indicates the number of surviving patients in each group corresponding to the intervals in the graph. Abbreviations: malnutrition status (MS)—non-malnutrition status (NMS).