Bioelectrical impedance phase angle relates to function, disease severity and prognosis in stable XXXX .

@entity1 @entity1386 @entity1030
BACKGROUND _ AIMS: Bioelectrical impedance analysis (BIA) provides a simple method to assess changes in body composition. Raw BIA variables such as phase angle provide direct information on cellular mass and integrity, without the assumptions inherent in estimating body compartments, e.g. @entity1386 ( @entity1386 ). Phase angle is a strong functional and prognostic marker in many disease states, but data in @entity1030 are lacking. Our aims were to describe the measurement of phase angle in @entity1 with stable @entity1030 and determine the construct and discriminate validity of phase angle by assessing its relationship with established markers of function, disease severity and prognosis. METHODS: 502 outpatients with stable @entity1030 were studied. Phase angle and @entity1386 by BIA, quadriceps strength (QMVC), 4-m gait speed (4MGS), 5 sit-to-stand time (5STS), incremental shuttle walk (ISW), and composite prognostic indices (ADO, iBODE) were measured. @entity1 were stratified into normal and low phase angle and @entity1386 index. RESULTS: Phase angle correlated positively with @entity1386 and functional outcomes (r  =  0.35-0.66, p  <  0.001) and negatively with prognostic indices (r  =  -0.35 to  -0.48, p  <  0.001). In regression models, phase angle was independently associated with ISW, ADO and iBODE whereas @entity1386 was removed. One hundred and seventy @entity1 (33.9% [95% CI, 29.9-38.1]) had a low phase angle. Phenotypic characteristics included lower QMVC, ISW, and 4MGS, higher 5STS, ADO and iBODE scores, and more exacerbations and hospital days in past year. The proportion of @entity1 to have died was significantly higher in @entity1 with low phase angle compared to those with normal phase angle (8.2% versus 3.6%, p  =  0.02). CONCLUSION: Phase angle relates to markers of function, disease severity and prognosis in @entity1 with @entity1030 . As a directly measured variable, phase angle offers more useful information than @entity1386 indices.
