Panisset Maya G, Desneves Kate, Ward Leigh C, Rafferty Jillian, Rodi Helena, Roff Geoff, El-Ansary Doa, Galea Mary P
Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.
Department of Dietetics and Nutrition, Austin Health, Heidelberg, VIC, Australia.
Spinal Cord. 2018 Apr;56(4):355-365. doi: 10.1038/s41393-017-0035-1. Epub 2017 Dec 28.
Psychometric.
Assess the validity of bioimpedance-based measures of fat-free mass (FFM) in acute SCI and of current definitions of obesity based on body mass index (BMI).
Australia.
All admissions within eight weeks of a new traumatic SCI were screened. 29% were eligible. 71% of those consented. Twenty participants (18 male) completed deuterium dilution (DD) and bioimpedance-based measurements of FFM. Thirteen also underwent dual-energy x-ray absorptiometry. Strength of relationships and agreement were examined using Lin's concordance coefficient and limits of agreement analysis, respectively. Sensitivity and specificity were calculated for three BMI cutoffs for obesity, using percentage fat mass (%FM) obtained from DD as reference.
Median time since injury was 41 days (IQR 28-48). FFM from DD and DXA were highly correlated but not identical. Concordance and agreement between DD and seven bioimpedance-based predictive equations are presented. The best-fitting equation demonstrated a low bias (+0.6 kg) and moderate dispersion (±5.2 kg). The cutoff for overweight in able-bodied people (BMI ≥25 kg/m) provided sensitivity of 43.8%, compared to 25% for the cut-off for obesity (BMI ≥30 kg/m). FM from bioimpedance gave the highest sensitivity (88.9%).
BMI demonstrates poor specificity to classify obesity in acute SCI. Present findings support the utility of bioimpedance-based measurements for estimating FFM in acute SCI for group comparisons. These results are generalizable to traumatic SCI 4-8 weeks post injury; however, the present data reflect a high proportion of high cervical injuries. Further research is indicated to establish validity for assessment of individuals and for longitudinal monitoring.
The present study was funded by a grant from the Institute for Safety, Compensation and Recovery Research (ISCRR Project #NGE-E-13-078). M Panisset was supported by an Australian Postgraduate Award. K Desneves was supported by the Austin Medical Research Foundation.
心理测量学研究。
评估基于生物电阻抗法测量急性脊髓损伤患者去脂体重（FFM）的有效性，以及基于体重指数（BMI）的现行肥胖定义的有效性。
澳大利亚。
对新发生创伤性脊髓损伤后八周内入院的所有患者进行筛查。29%符合条件，其中71%同意参与研究。20名参与者（18名男性）完成了氘稀释法（DD）和基于生物电阻抗法的去脂体重测量。13名参与者还接受了双能X线吸收法检查。分别使用林氏一致性系数和一致性界限分析来检验关系强度和一致性。以DD法测得的体脂百分比（%FM）为参考，计算了三个肥胖BMI临界值的敏感性和特异性。
受伤后的中位时间为41天（四分位间距28 - 48天）。DD法和双能X线吸收法测得的去脂体重高度相关但不完全相同。列出了DD法与七个基于生物电阻抗法的预测方程之间的一致性和吻合度。拟合度最佳的方程显示偏差较小（+0.6千克），离散度适中（±5.2千克）。健全人群中超重的临界值（BMI≥25千克/平方米）的敏感性为43.8%，而肥胖临界值（BMI≥30千克/平方米）的敏感性为25%。生物电阻抗法测得的体脂百分比敏感性最高（88.9%）。
BMI对急性脊髓损伤患者肥胖分类的特异性较差。目前的研究结果支持基于生物电阻抗法测量在急性脊髓损伤患者组间比较中估算去脂体重的实用性。这些结果可推广至受伤后4 - 8周的创伤性脊髓损伤患者；然而，目前的数据反映出高颈段损伤患者比例较高。需要进一步研究以确定其在个体评估和纵向监测中的有效性。
本研究由安全、补偿与康复研究所（ISCRR项目编号：NGE - E - 13 - 078）的一项拨款资助。M·帕尼塞特获得澳大利亚研究生奖学金支持。K·德斯内夫斯获得奥斯汀医学研究基金会支持。
