Low phase angle determined by bioelectrical impedance analysis is associated with malnutrition and nutritional risk...

This study determined the association between phase angle (PhA), by bioelectrical impedance analysis (BIA) and nutritional risk by Nutritional Risk Screening (NRS-2002), Subjective Global Assessment (SGA), hospital length of stay (LOS) and 30 day non-survival in patients at hospital admission compared to healthy controls.

PhA was determined by BIA in patients (n = 983, 52.7 ± 21.5 yrs, M 520) and compared to healthy age-, sex- and height-matched controls. Low PhA was set at <5.0° (men) and <4.6° (women) as previously determined (Kyle, in press).

PhA was lower in patients (men 6.0 ± 1.4°, women 5.0 ± 1.3°) than controls (men 7.1 ± 1.2°, women 6.0 ± 1.2°, un-paired t-test p < 0.001). Patients were more likely to have low PhA than controls: NRS-2002: no risk (relative risk (RR) 1.7, 95th confidence interval (CI) 1.2-2.3), moderate risk (RR 4.5, CI 3.4-5.8) and severe risk (RR 7.5, CI 5.9-9.4); similar results were obtained by SGA; LOS ≥21 days (RR 6.9, CI 5.1-9.1) and LOS 5-20 days (RR 5.2, CI 3.9-6.9) and non-survivors (RR 3.1, CI 2.1-3.4) compared to survivors.

There is a significant association between low PhA and nutritional risk, LOS and non-survival. PhA is helpful to identify patients who are at nutritional risk at hospital admission in order to limit the number of in-depth nutritional assessments.