Faria Silvia L, Faria Orlando P, Cardeal Mariane D A, Ito Marina Kiyomi
, Gastrocirurgia, Brasilia, Brazil,
Obes Surg. 2014 Sep;24(9):1476-80. doi: 10.1007/s11695-014-1190-5.
Body mass index (BMI) is the most common parameter for classifying nutritional status. However, body composition (BC) may vary considerably among individuals with identical BMIs; consequently, we need to assess BC efficiently. Bariatric surgery is the most effective method for treating obesity. To improve quality assessment of postoperative weight loss, it is essential to assess BC. Multi-frequency bioelectrical impedance analysis (BIA) is a practical assessment instrument, though limited when applied among the obese population. Despite dual-energy X-ray absorptiometry (DXA) being the current reference standard, it has physical limitations which restrict its practical application. This study, therefore, sought to correlate the results of BC assessments of same patient population using BIA and DXA.
This was a cross-sectional validation study with patients invited to undergo a multi-frequency BIA (Inbody 720®) and afterwards a DXA examination Statistical analyses were done using the intraclass correlation coefficient (ICC), paired t-test and the Bland-Altman plot analysis.
A total of 108 patients were randomly selected, with 73 meeting the criteria for study inclusion. Most were female (89%) and had an average BMI of 40.17 ± 4.08 kg/m(2). An almost perfect correlation of fat (kg) and fat-free mass (kg) was found in results from the BIA and DXA examination (ICC = 0.832 and ICC = 0.899, respectively). A substantial correlation was also found between the percentage of body fat (%BF) and the percentage of fat-free mass (%FFM). The comparison made between the BIA and DXA using the t-test showed significant differences between all parameters. The Bland-Altman plot showed that the BIA method tends to underestimate the FM and overestimate the LM measurements when compared with DXA.
BIA proved to be a safe alternative for assessing BC in clinically severely obese patients and thus provides a more accessible evaluation tool for this population. But, consideration should be given to the formula added to the BIA measurement, adjusting the values to differences observed in order to reduce errors when compared with the DXA measurements.
体重指数（BMI）是用于分类营养状况的最常见参数。然而，在BMI相同的个体中，身体成分（BC）可能存在很大差异；因此，我们需要有效地评估身体成分。减肥手术是治疗肥胖症最有效的方法。为了提高术后体重减轻的质量评估，评估身体成分至关重要。多频生物电阻抗分析（BIA）是一种实用的评估工具，尽管在肥胖人群中应用时存在局限性。尽管双能X线吸收法（DXA）是当前的参考标准，但它存在物理限制，限制了其实际应用。因此，本研究旨在使用BIA和DXA对同一患者群体的身体成分评估结果进行相关性分析。
这是一项横断面验证研究，邀请患者接受多频BIA（Inbody 720®）检查，之后进行DXA检查。使用组内相关系数（ICC）、配对t检验和Bland-Altman图分析进行统计分析。
总共随机选择了108名患者，其中73名符合研究纳入标准。大多数为女性（89%），平均BMI为40.17±4.08kg/m²。BIA和DXA检查结果显示脂肪（kg）和去脂体重（kg）之间几乎具有完美的相关性（ICC分别为0.832和0.899）。身体脂肪百分比（%BF）和去脂体重百分比（%FFM）之间也存在显著相关性。使用t检验对BIA和DXA进行比较，结果显示所有参数之间均存在显著差异。Bland-Altman图显示，与DXA相比，BIA方法往往低估脂肪量（FM）并高估瘦体重（LM）测量值。
BIA被证明是临床上评估重度肥胖患者身体成分的一种安全替代方法，因此为该人群提供了一种更易于使用的评估工具。但是，应考虑添加到BIA测量中的公式，根据观察到的差异调整数值，以减少与DXA测量相比时的误差。
