Gerontology Department and Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium; Frailty in Ageing (FRIA) Research Department, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium.
Gerontology Department and Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium; Frailty in Ageing (FRIA) Research Department, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090, Brussels, Belgium; Rehabilitation Sciences Research Department (RERE), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels, Belgium.
Clin Nutr. 2019 Aug;38(4):1756-1764. doi: 10.1016/j.clnu.2018.07.029. Epub 2018 Aug 2.
To date, the accuracy of bio-impedance (BIA) to assess body composition & sarcopenia in persons aged 80 and over remains unclear.
We aimed to evaluate the agreement between dual energy X-ray absorptiometry (DXA) and BIA equations to determine lean mass, as well as their suitability to identify sarcopenia.
174 community dwelling well-functioning persons (83 women, 91 men) aged 80 and over were included. Appendicular lean mass (ALM) was predicted using BIA-based equations available in literature, and compared to DXA outcomes. Through cross-validation and stepwise multiple linear regression, a new ALM-formula was generated suitable for this population.
Literature-based BIA equations systematically overestimated ALM. The new prediction formula that we propose for the 80+ is: ALM = 0,827+(0,19Impedance Index)+(2,101Sex)+(0,079*Weight); R = 0,888; SEE = 1,450 kg. Sarcopenia classification based on our new BIA equation for ALM showed better agreement with DXA (k ≥ 0,454) compared to literature-based BIA equations (k < 0,368).
Despite the high correlation between both methods, literature-based BIA equations consistently overestimate ALM compared to DXA in persons aged 80 and over. We proposed a new equation for ALM, reaching higher agreement with DXA and thus improving the accuracy of BIA for this specific age group.
迄今为止，生物阻抗（BIA）评估 80 岁及以上人群身体成分和肌肉减少症的准确性仍不清楚。
我们旨在评估双能 X 射线吸收法（DXA）和 BIA 方程在确定瘦体重方面的一致性，并评估它们识别肌肉减少症的适用性。
共纳入 174 名 80 岁及以上、社区居住、功能良好的个体（83 名女性，91 名男性）。使用文献中提供的基于 BIA 的方程预测四肢瘦体重（ALM），并与 DXA 结果进行比较。通过交叉验证和逐步多元线性回归，生成一种适用于该人群的新 ALM 公式。
文献中基于 BIA 的方程系统高估了 ALM。我们为 80 岁以上人群提出的新预测公式为：ALM=0.827+(0.19阻抗指数)+(2.101性别)+(0.079*体重)；R=0.888；SEE=1.450 千克。与基于文献的 BIA 方程相比（k<0.368），基于我们新的 BIA 方程的 ALM 肌肉减少症分类与 DXA 具有更好的一致性（k≥0.454）。
尽管两种方法具有高度相关性，但与 DXA 相比，基于文献的 BIA 方程在 80 岁及以上人群中始终高估了 ALM。我们提出了一种新的 ALM 方程，与 DXA 的一致性更高，从而提高了 BIA 在该特定年龄组中的准确性。
