Bioelectrical impedance phase angle relates to function, disease severity and prognosis in stable chronic obstructive pulmonary disease
Bioelectrical impedance phase angle relates to function, disease severity and prognosis in stable chronic obstructive pulmonary disease
复制标题
DOI：
10.1016/j.clnu.2014.12.020
复制
发表时间：
2015-12-01
影响因子：
6.3
通讯作者：
Man, William D. -C.
中科院分区：
文献类型：
--
作者：
Maddocks, Matthew;Kon, Samantha S. C.;Man, William D. -C.
背景与目的：生物电阻抗分析（BIA）提供了一种评估机体成分变化的简便方法。原始的BIA变量，如相位角，提供了细胞质量和完整性的直接信息，没有假设。固有的估计身体间隔，如无脂质量（FFM）。在许多疾病状态中，相角是一个强有力的功能和预后指标，但在COPD中缺乏相关数据。我们的目的是描述稳定型COPD患者的相角测量，并通过评估相角与功能、疾病严重程度和预后的既定标志物的关系来确定相角的结构和判别效度。方法：对502例稳定期COPD门诊患者进行分析。测量相位角和FFM （BIA）、股四头肌力量（QMVC）、4 m步速（4MGS）、5次坐立时间（5STS）、增量来回行走（ISW）和综合预后指标（ADO、iBODE）。将患者分为正常相角、低相角和FFM指数。结果：相位角与FFM和功能结局呈正相关（r = 0.35 ~ 0.66, p < 0.001），与预后指标呈负相关（r = -0.35 ~ -0.48, p < 0.001）。在回归模型中，相位角与ISW、ADO和iBODE独立相关，而FFM被去除。170例患者（33.9% [95% Cl, 29.9-38.1]）存在低相角。表型特征包括较低的QMVC、ISW和4MGS，较高的5STS、ADO和iBODE评分，以及过去一年的加重和住院天数。低相角患者的死亡比例明显高于正常相角患者（8.2%比3.6%,p = 0.02）。结论：相位角与COPD患者功能、病情严重程度及预后指标有关。作为一个直接测量的变量，相位角提供了比无脂质量指数更有用的信息。(C) 2015 Elsevier Ltd和欧洲临床营养与代谢学会。版权所有。
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. fat-free mass (FFM). Phase angle is a strong functional and prognostic marker in many disease states, but data in COPD are lacking. Our aims were to describe the measurement of phase angle in patients with stable COPD 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 COPD were studied. Phase angle and FFM 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. Patients were stratified into normal and low phase angle and FFM index.Results: Phase angle correlated positively with FFM 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 FFM was removed. One hundred and seventy patients (33.9% [95% Cl, 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 patients to have died was significantly higher in patients 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 patients with COPD. As a directly measured variable, phase angle offers more useful information than fat-free mass indices. (C) 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.