Translational Medicine Program, The Hospital for Sick Children, Toronto, Canada; The Childhood Acute Illness & Nutrition Network, Nairobi, Kenya.
Global Child Health Group, Emma Children's Hospital, Amsterdam University Medical Centres, Amsterdam, the Netherlands; Department of Pediatrics and Child Health, College of Medicine, University of Malawi, Blantyre, Malawi.
Clin Nutr. 2021 Apr;40(4):2078-2090. doi: 10.1016/j.clnu.2020.09.031. Epub 2020 Oct 1.
BACKGROUND & AIMS: Severe Acute Malnutrition (SAM) in children is determined using anthropometry. However, bio-electrical impedance (BI) analysis could improve the estimation of altered body composition linked to edema and/or loss of lean body mass in children with SAM. We aimed to assess: 1) the changes in BI parameters during clinical stabilization and 2) whether BI parameters add prognostic value for clinical outcome beyond the use of anthropometry.
This prospective observational study enrolled children, aged 6-60 months, that were admitted at Queen Elizabeth Central Hospital in Blantyre, Malawi, for complicated SAM (i.e., having either severe wasting or edematous SAM with a complicating illness). Height, weight, mid-upper arm circumference (MUAC), and BI were measured on admission and after clinical stabilization. BI measures were derived from height-adjusted indices of resistance (R/H), reactance (Xc/H), and phase angle (PA) and considered to reflect body fluids and soft tissue in BI vector analysis (BIVA).
We studied 183 children with SAM (55% edematous; age 23.0 ± 12.0 months; 54% male) and 42 community participants (age 20.1 ± 12.3 months; male 62%). Compared to community participants, the BIVA of children with edematous SAM were short with low PA and positioned low on the hydration axis which reflects severe fluid retention. In contrast, children with severe wasting had elongated vectors with a PA that was higher than children with edematous SAM but lower than community participants. Their BIVA position fell within the top right quadrant linked to leanness and dehydration. BIVA from severely wasted and edematous SAM patients differed between groups and from community children both at admission and after stabilization (p < 0.001). Vector position shifted during treatment only in children with edematous SAM (p < 0.001) and showed a upward translation suggestive of fluid loss. While PA was lower in children with SAM, PA did not contribute more than anthropometry alone towards explaining mortality, length of stay, or time-to-discharge or time-to-mortality. The variability and heterogeneity in BI measures was high and their overall added predictive value for prognosis of individual children was low.
BIVA did not add prognostic value over using anthropometry alone to predict clinical outcome. Several implementation challenges need to be optimized. Thus, in low-resource settings, the routine use of BI in the management of pediatric malnutrition is questionable without improved implementation.
儿童严重急性营养不良（SAM）的诊断采用人体测量学。然而，生物电阻抗（BI）分析可以改善对水肿和/或 SAM 儿童瘦体组织丢失相关的改变身体成分的评估。我们旨在评估：1）临床稳定过程中 BI 参数的变化；2）BI 参数是否比人体测量学更能为临床结局提供预后价值。
这项前瞻性观察性研究纳入了马拉维布兰太尔伊丽莎白女王中央医院收治的年龄在 6-60 个月的患有复杂 SAM（即患有严重消瘦或水肿性 SAM 并伴有合并症的儿童）的儿童。在入院时和临床稳定后测量身高、体重、中上臂周长（MUAC）和 BI。BI 测量值由身高调整的电阻（R/H）、电抗（Xc/H）和相位角（PA）指数得出，并考虑在 BI 矢量分析（BIVA）中反映身体液体和软组织。
我们研究了 183 名患有 SAM（55%水肿；年龄 23.0±12.0 个月；54%为男性）和 42 名社区参与者（年龄 20.1±12.3 个月；男性 62%）的儿童。与社区参与者相比，水肿性 SAM 儿童的 BIVA 短，PA 低，位于水化轴的低端，反映出严重的液体潴留。相比之下，严重消瘦的儿童具有拉长的向量，PA 高于水肿性 SAM 儿童，但低于社区参与者。他们的 BIVA 位置落在与消瘦和脱水相关的右上角象限内。入院时和稳定后，严重消瘦和水肿性 SAM 患者的 BIVA 与组间和社区儿童的 BIVA 均存在差异（p<0.001）。只有水肿性 SAM 儿童的向量位置在治疗过程中发生了变化（p<0.001），并出现了提示液体丢失的向上平移。虽然 SAM 儿童的 PA 较低，但 PA 并没有比人体测量学单独更能解释死亡率、住院时间、出院时间或死亡时间。BI 测量的变异性和异质性很高，其对个体儿童预后的总体预测价值较低。
BIVA 并没有比单独使用人体测量学更能提供预后价值，以预测临床结局。需要优化几个实施方面的问题。因此，在资源匮乏的环境中，在没有改进实施的情况下，BI 在儿科营养不良管理中的常规使用存在疑问。
