Mercadal Lucile, Metzger Marie, Haymann Jean Philippe, Thervet Eric, Boffa Jean-Jacques, Flamant Martin, Vrtovsnik François, Gauci Cédric, Froissart Marc, Stengel Bénédicte
Institut National de la Santé et de la Recherche Médicale U1018, CESP Centre for research in Epidemiology and Population Health, Epidemiology of Diabetes, Obesity, and Kidney Diseases Team, Villejuif, France ; Department of Nephrology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
Institut National de la Santé et de la Recherche Médicale U1018, CESP Centre for research in Epidemiology and Population Health, Epidemiology of Diabetes, Obesity, and Kidney Diseases Team, Villejuif, France ; Univ Paris Sud 11, UMRS 1018, Villejuif, France.
PLoS One. 2014 Feb 19;9(2):e84144. doi: 10.1371/journal.pone.0084144. eCollection 2014.
Iron disorders are common and complex in chronic kidney disease (CKD). We sought to determine whether a 3-marker index would improve the classification of iron disorders in CKD anaemia.
We studied the association between Hb level and iron indexes combining 2 or 3 of the following markers: serum ferritin (<40 ng/mL), transferrin saturation (TSAT<20%) and total iron binding capacity (TIBC<50 µmol/L) in 1011 outpatients with non-dialysis CKD participating in the Nephrotest study. All had glomerular filtration rates measured (mGFR) by (51)Cr-EDTA renal clearance; 199 also had hepcidin measures.
The TSAT-TIBC-ferritin index explained Hb variation better than indexes combining TSAT-TIBC or ferritin-TSAT. It showed hypotransferrinaemia and non-inflammatory functional iron deficiency (ID) to be more common than either absolute or inflammatory ID: 20%, 19%, 6%, and 2%, respectively. Hb was lower in all abnormal, compared with normal, iron profiles, and decreased more when mGFR was below 30 mL/min/1.73 m(2) (interaction p<0.0001). In patients with mGFR<30 mL/min/1.73 m(2), the Hb decreases associated with hypotransferrinaemia, non-inflammatory functional ID, and absolute ID were 0.83±0.16 g/dL, 0.51±0.18 and 0.89±0.29, respectively. Compared with normal iron profiles, hepcidin was severely depressed in absolute ID but higher in hypotransferrinaemia.
The combined TSAT-TIBC-ferritin index identifies hypotransferrinaemia and non-inflammatory functional ID as the major mechanisms of iron disorders in CKD anaemia. Both disorders were associated with a greater decrease in Hb when mGFR was <30 mL/min/1.73 m(2). Taking these iron profiles into account may be useful in stratifying patients in clinical trials of CKD anaemia and might improve the management of iron therapy.
铁代谢紊乱在慢性肾脏病（CKD）中常见且复杂。我们试图确定一个三指标指数是否能改善CKD贫血中铁代谢紊乱的分类。
我们在参与Nephrotest研究的1011例非透析CKD门诊患者中，研究血红蛋白（Hb）水平与结合以下2种或3种指标的铁指标之间的关联：血清铁蛋白（<40 ng/mL）、转铁蛋白饱和度（TSAT<20%）和总铁结合力（TIBC<50 μmol/L）。所有患者均通过（51）Cr - EDTA肾清除率测定肾小球滤过率（mGFR）；199例患者还检测了铁调素水平。
TSAT - TIBC - 铁蛋白指数比结合TSAT - TIBC或铁蛋白 - TSAT的指数能更好地解释Hb变化。结果显示，低转铁蛋白血症和非炎症性功能性缺铁（ID）比绝对缺铁或炎症性ID更常见，分别为20%、19%、6%和2%。与正常铁指标相比，所有异常铁指标状态下的Hb均较低，且当mGFR低于30 mL/min/1.73 m²时下降更明显（交互作用p<0.0001）。在mGFR<30 mL/min/1.73 m²的患者中，与低转铁蛋白血症、非炎症性功能性ID和绝对ID相关的Hb下降分别为0.83±0.16 g/dL、0.51±0.18和0.89±0.29。与正常铁指标相比，铁调素在绝对ID时严重降低，但在低转铁蛋白血症时升高。
联合TSAT - TIBC - 铁蛋白指数可确定低转铁蛋白血症和非炎症性功能性ID是CKD贫血中铁代谢紊乱的主要机制。当mGFR<30 mL/min/1.73 m²时，这两种紊乱均与Hb更大幅度下降相关。在CKD贫血的临床试验中考虑这些铁指标状态可能有助于对患者进行分层，并可能改善铁剂治疗的管理。
