Can phase angle determined by bioelectrical impedance analysis assess nutritional risk? A comparison between healthy and hospitalized subjects

Background Er aims: Low phase angle (PhA) by bioelectrical impedance analysis (BIA), is associated with increased morbidity and nutritional risk. This study determined the cut-off values for PhA compared to Nutritional Risk Screening (NRS-2002) and Subjective Global Assessment (SGA) in patients at hospital admission, and evaluated the association between PhA and serum albumin. Methods: PhA was determined in patients (Men (M)/Women (W) = 382/267), and healthy age-, sex- and height-matched controls. Sensitivity and specificity were calculated for PhA compared to NRS-2002, SGA and serum albumin. The cut-off values were assessed by receiver operator characteristics area under the curve (ROC-AUC). Results: The best PhA cut-offs were 5.0 degrees and 4.6 degrees in M/W. The sensitivity for NRS-2002 was 70.0/58.1% (M/W); SGA: 73.3/64.5%; albumin: 58.8/23.5%; specificity for NRS-2002: 85.1/81.7%.(M/W); SGA: 76.6/76.1% and albumin: 93.2/96.6%. The PhA showed a ROC-AUC for NRS-2002 of 0.85/0.80 (M/W); SGA: 0.83/0.80 and albumin: 0.85/0.91. Patients with albumin levels <35 g/L had a relative risk of 7.5 to have low PhA compared to patients with >= 35 g/L Conclusions: The consistent sensitivity and specificity between PhA and three screening tools strengthens the validity of our study. PhA appears to be a useful screening tool to assess nutritional risk without having to measure weight or height. (C) 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.