Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Sweden.
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; Section for Colorectal Cancer Screening, Cancer Registry of Norway, Norway.
Clin Nutr ESPEN. 2020 Dec;40:201-207. doi: 10.1016/j.clnesp.2020.09.021. Epub 2020 Oct 3.
BACKGROUND & AIMS: Although previous research show high correlation between fat-free mass (FFM) measured by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), the validity of BIA to track longitudinal changes in FFM is uncertain. Thus, the aim of this study was to validate the ability of BIA to assess changes in FFM during 6 months of recovery from non-metastatic colorectal cancer (CRC).
A total of 136 women and men (50-80 years) with stage I-III CRC and a wide range of baseline FFM (35.7-73.5 kg) were included in the study. Body composition was measured at study baseline within 2-9 months of surgery and again 6 months later. Whole-body BIA FFM estimates (FFM) were calculated using three different equations (manufacturer's, Schols' and Gray's) before comparison to FFM estimates obtained by DXA (FFM).
Correlation between changes in FFM and FFM was intermediate regardless of equation (r ≈ 0.6). The difference in change of FFM was significant compared to FFM, using all three equations and BIA overestimated both loss and gain. However, BIA showed 100% sensitivity and about 90% specificity to identify individuals with ≥5% loss in FFM, using all three equations. Sensitivity of FFM to detect a smaller loss of FFM (60-76%) or a gain in FFM of ≥5% (33-62%) was poor.
In a well-nourished population of non-metastatic CRC patients, a single-frequency whole-body BIA device yielded imprecise data on changes in FFM, regardless of equation. BIA is thus not a valid option for quantifying changes in FFM in individuals. However, BIA could be used to identify patients with loss in FFM ≥5% in this population. The validity of BIA to monitor changes in FFM warrants further investigation before implementation in clinical praxis.
尽管先前的研究表明，体脂量（FFM）通过生物电阻抗分析（BIA）和双能 X 射线吸收法（DXA）测量具有高度相关性，但 BIA 跟踪 FFM 纵向变化的有效性尚不确定。因此，本研究旨在验证 BIA 评估非转移性结直肠癌（CRC）康复 6 个月期间 FFM 变化的能力。
共纳入 136 名年龄在 50-80 岁、I-III 期 CRC 且基线 FFM 范围较宽（35.7-73.5kg）的女性和男性患者。在手术后 2-9 个月内和 6 个月后，对患者进行研究基线时的身体成分测量。使用三种不同的方程（制造商的、Schols 的和 Gray 的）计算全身 BIA FFM 估计值（FFM），然后与 DXA （FFM）获得的 FFM 估计值进行比较。
无论方程如何，FFM 变化与 FFM 之间的相关性均为中等（r≈0.6）。与 FFM 相比，所有三种方程和 BIA 测量的 FFM 变化均存在显著差异，且 BIA 高估了 FFM 的损失和增益。然而，使用所有三种方程，BIA 对识别 FFM 损失≥5%的个体具有 100%的敏感性和约 90%的特异性。FFM 检测 FFM 较小损失（60-76%）或 FFM 增益≥5%（33-62%）的敏感性较差。
在非转移性 CRC 患者这个营养良好的人群中，无论使用哪种方程，单频全身 BIA 设备在 FFM 变化方面的数据都不够精确。因此，BIA 不是量化个体 FFM 变化的有效方法。但是，BIA 可以用于识别该人群中 FFM 损失≥5%的患者。在将 BIA 应用于临床实践之前，还需要进一步研究其监测 FFM 变化的有效性。
