Wang Wenqiao, Feng Yijie, Long Qi, Chen Fei, Chen Yuzhi, Ma Ming, Mao Shanshan
Department of Clinical Nutrition, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
Department of Neurology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
Front Neurol. 2022 Nov 18;13:1034894. doi: 10.3389/fneur.2022.1034894. eCollection 2022.
Body composition analysis is a valuable tool for assessing and monitoring the nutritional status of children with spinal muscular atrophy (SMA). This study was designed to compare the consistency of bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), as the gold standard method for assessing body composition in clinical practice when treating children with type II and III SMA.
From 2019 to 2021, we performed a retrospective analysis of body composition by DXA and BIA measurement methods in patients with type II and III SMA treated at a Chinese tertiary children's hospital. Fat mass (FM), muscle mass (MM), bone mineral content (BMC), and visceral fat area (VFA) were compared using paired sample t-tests. We calculated Lin's concordance correlation coefficient (CCC) and Spearman correlation coefficient to verify the correlation between DXA and BIA measurements. Bland-Altman analysis was used to assess the consistency of the two methods.
Fifty-seven children with type II and III SMA were recruited. Compared with body composition measured by DXA, the average FM measured by BIA is significantly lower ( <0.001), whereas the average MM, BMC, and VFA measured by BIA are significantly higher ( < 0.001) in children with SMA. Overall, the difference between MM (Delta [BIA-DAX] = 1.6 kg) and FM (Delta [BIA-DAX] = -1.6 kg) measured by DXA and BIA was minor, whereas the difference of VFA (Delta [BIA-DAX] = -43.5 cm) was significantly large. Correlation analysis indicated a substantial correlation of MM (CCC = 0.96 [95% confidence interval (CI) = 0.93-0.98], = 0.967 [ < 0.0001]) and FM (CCC = 0.95 [95% CI = 0.92-0.97], = 0.953 [ < 0.0001]), and poor correlation of BMC (CCC = 0.61 [95% CI = 0.42-0.75], = 0.612 [ < 0.0001]) and VFA (CCC = 0.54 [95% CI = 0.33-0.70], = 0.689 [ < 0.0001]) measurements between the two methods. The Bland-Altman analysis suggests that the majority of participants were within LOA. In addition, differences in MM and VFA measurements between BIA and DAX increased according to patients' increasing height, whereas differences in FM and BMC did not differ with height.
BIA overestimates MM and underestimates the FM, BMC, and VFA in children with SMA compared with DXA measurements. Overall, the non-invasive, easy-to-use, and repeatable BIA measurements were found to be in good agreement with DXA measurements, especially for FM and MM, which are essential parameters for the nutritional evaluation of children with SMA.
身体成分分析是评估和监测脊髓性肌萎缩症（SMA）患儿营养状况的重要工具。本研究旨在比较生物电阻抗分析（BIA）与双能X线吸收法（DXA）的一致性，DXA是临床实践中治疗II型和III型SMA患儿时评估身体成分的金标准方法。
2019年至2021年，我们对一家中国三级儿童医院治疗的II型和III型SMA患者通过DXA和BIA测量方法进行身体成分的回顾性分析。使用配对样本t检验比较脂肪量（FM）、肌肉量（MM）、骨矿物质含量（BMC）和内脏脂肪面积（VFA）。我们计算了林氏一致性相关系数（CCC）和斯皮尔曼相关系数，以验证DXA和BIA测量之间的相关性。采用Bland-Altman分析评估两种方法的一致性。
招募了57名II型和III型SMA患儿。与DXA测量的身体成分相比，SMA患儿中通过BIA测量的平均FM显著更低（<0.001），而通过BIA测量的平均MM、BMC和VFA显著更高（<0.001）。总体而言，DXA和BIA测量的MM（差值[BIA - DAX]=1.6 kg）和FM（差值[BIA - DAX]= - 1.6 kg）之间的差异较小，而VFA的差异（差值[BIA - DAX]= - 43.5 cm）显著较大。相关性分析表明，MM（CCC = 0.96 [95%置信区间（CI）= 0.93 - 0.98]，= 0.967 [<0.0001]）和FM（CCC = 0.95 [95% CI = 0.92 - 0.97]，= 0.953 [<0.0001]）具有高度相关性，而两种方法之间BMC（CCC = 0.61 [95% CI = 0.42 - 0.75]，= 0.612 [<0.0001]）和VFA（CCC = 0.54 [95% CI = 0.33 - 0.70]，= 0.689 [<0.0001]）测量的相关性较差。Bland-Altman分析表明，大多数参与者在一致性界限内。此外，BIA和DAX之间MM和VFA测量的差异随着患者身高的增加而增加，而FM和BMC的差异与身高无关。
与DXA测量相比，BIA高估了SMA患儿的MM，低估了FM、BMC和VFA。总体而言，发现无创、易用且可重复的BIA测量与DXA测量具有良好的一致性，特别是对于FM和MM，它们是SMA患儿营养评估的关键参数。
