Barcelona Centre for International Heath Research, Hospital Clínic, University of Barcelona, Barcelona, Spain.
PLoS One. 2012;7(11):e50584. doi: 10.1371/journal.pone.0050584. Epub 2012 Nov 27.
While WHO guidelines recommend iron supplements to only iron-deficient children in high infection pressure areas, these are rarely implemented. One of the reasons for this is the commonly held view that iron supplementation increases the susceptibility to some infectious diseases including malaria. Secondly, currently used markers to diagnose iron deficiency are also modified by infections. With the objective of improving iron deficiency diagnosis and thus, its management, we evaluated the performance of iron markers in children exposed to high infection pressure.
METHODOLOGY/PRINCIPAL FINDINGS: Iron markers were compared to bone marrow findings in 180 anaemic children attending a rural hospital in southern Mozambique. Eighty percent (144/180) of the children had iron deficiency by bone marrow examination, 88% (155/176) had an inflammatory process, 66% (119/180) had moderate anaemia, 25% (45/180) severe anaemia and 9% (16/180) very severe anaemia. Mean cell haemoglobin concentration had a sensitivity of 51% and specificity of 71% for detecting iron deficiency. Soluble transferrin receptor (sTfR) and soluble transferrin receptor/log ferritin (TfR-F) index (adjusted by C reactive protein) showed the highest areas under the ROC curve (AUC(ROC)) (0.75 and 0.76, respectively), and were the most sensitive markers in detecting iron deficiency (83% and 75%, respectively), but with moderate specificities (50% and 56%, respectively).
CONCLUSIONS/SIGNIFICANCE: Iron deficiency by bone marrow examination was extremely frequent in these children exposed to high prevalence of infections. However, even the best markers of bone marrow iron deficiency did not identify around a quarter of iron-deficient children. Tough not directly extrapolated to the community, these findings urge for more reliable, affordable and easy to measure iron indicators to reduce the burden of iron deficiency anaemia in resource-poor settings where it is most prevalent.
世界卫生组织（WHO）指南建议在高感染压力地区，仅为缺铁的儿童补充铁剂，但这些建议很少得到实施。其中一个原因是，人们普遍认为铁补充剂会增加某些传染病（包括疟疾）的易感性。其次，目前用于诊断缺铁的标志物也会受到感染的影响。为了改善缺铁的诊断，从而改善其管理，我们评估了在高感染压力下暴露的儿童的铁标志物的性能。
方法/主要发现：在莫桑比克南部的一家农村医院，我们将铁标志物与骨髓检查结果进行了比较，共纳入了 180 名贫血儿童。骨髓检查发现 80%（144/180）的儿童患有缺铁症，88%（176/180）的儿童存在炎症过程，66%（180/180）的儿童有中度贫血，25%（45/180）有严重贫血，9%（16/180）有极严重贫血。平均细胞血红蛋白浓度（MCV）对缺铁的敏感性为 51%，特异性为 71%。可溶性转铁蛋白受体（sTfR）和可溶性转铁蛋白受体/铁蛋白（TfR-F）指数（根据 C 反应蛋白调整）的曲线下面积（AUC（ROC））最高（分别为 0.75 和 0.76），且是检测缺铁最敏感的标志物（分别为 83%和 75%），但特异性适中（分别为 50%和 56%）。
在这些暴露于高感染率的儿童中，骨髓检查发现的缺铁症极为常见。然而，即使是骨髓铁缺乏的最佳标志物也无法识别四分之一左右的缺铁儿童。虽然这些发现不能直接外推到社区，但在资源匮乏地区，缺铁性贫血最为普遍，这些发现迫切需要更可靠、经济实惠且易于测量的铁指标，以减轻缺铁性贫血的负担。
