Servicio de Nefrología, IIS-Fundación Jiménez Díaz, Fundación Renal Íñigo Álvarez de Toledo, Madrid, Spain.
Nefrologia. 2013;33(4):495-505. doi: 10.3265/Nefrologia.pre2013.Apr.11979.
Malnutrition has been described in patients with chronic kidney disease as well as its association with cardiovascular risk and mortality in haemodialysis patients. Recently, the new term "protein energy wasting" has been proposed with new diagnostic criteria (biochemical and anthropometric markers) for early identification of patients at risk for protein energy wasting and mortality. The aim of this study was to examine the prevalence, evolution over time and prognostic significance of PEW in a Spanish dialysis centre for the first time in Spain.
an observational study that included 122 prevalent haemodialysis patients at our centre. Between January 2010 and October 2012, three visits were carried out in which clinical, biochemical, anthropometric and body composition parameters were collected using BIS (bioelectrical impedance spectroscopy) along with their respective dialytic characteristics, in accordance with the criteria of the new definition. We analysed the prevalence of PEW in each visit, progression of the malnutrition parameters and factors potentially associated with PEW. After a mean follow-up period of 461 days, we analysed survival. Statistical analysis was performed using the R software.
The prevalence of PEW remained constant over time: 37% at baseline visit, 40.5% at 12 months and 41.1% at 24 months. With the introduction of the dynamic variable muscle mass loss, included in the definition of PEW, prevalence increased to 50% at 24 months. The PEW situation is dynamic, as demonstrated by the fact that 26%-36% of patients without PEW develop it de novo each year and 12%-30% annually recover from this situation. The presence of PEW was associated with higher rates of resistance to erythropoietin (irEPO) and higher pulse pressure at the end of dialysis. In the multivariable regression model, PEW predictive clinical variables were over-hydration, irEPO, intracellular water and the extracellular water/intracellular water ratio. Twenty-six (21%) patients died. The Kaplan-Meier curve did not show any differences in mortality risk between patients with and those without PEW, but the loss of muscle mass was associated with increased mortality.
The present observational study highlights the high prevalence of PEW, which has a dynamic nature in haemodialysis patients. Only the criterion of muscle mass loss (increased protein catabolism) was associated with increased mortality, while the other PEW criteria according to the ISRNM classification were not associated with increased mortality. We also observed a state of over-hydration in patients with PEW. This state of over-hydration (increased extracellular water due to occupation of muscle loss without an increase in total body water) cannot be evaluated by dry weight or the body mass index. Intervention studies are necessary in order to assess whether or not the prevention of sarcopaenia improves survival.
慢性肾脏病患者存在营养不良，且与血液透析患者的心血管风险和死亡率相关。最近，提出了新的术语“蛋白质能量消耗”，并制定了新的诊断标准（生化和人体测量标志物），以便早期识别有蛋白质能量消耗和死亡风险的患者。本研究旨在首次在西班牙的一个透析中心检查 PEW 在西班牙的流行率、随时间的演变和预后意义。
这是一项观察性研究，纳入了我们中心的 122 例现患血液透析患者。在 2010 年 1 月至 2012 年 10 月期间，进行了三次就诊，使用 BIS（生物电阻抗谱）收集临床、生化、人体测量和身体成分参数，以及各自的透析特征，符合新定义的标准。我们分析了每次就诊时 PEW 的流行率、营养不良参数的进展以及与 PEW 相关的潜在因素。经过平均 461 天的随访，我们分析了生存率。使用 R 软件进行统计分析。
PEW 的患病率在整个研究期间保持不变：基线就诊时为 37%，12 个月时为 40.5%，24 个月时为 41.1%。随着蛋白质能量消耗定义中包含的肌肉质量损失这一动态变量的引入，24 个月时患病率增加至 50%。PEW 的情况是动态的，因为每年有 26%-36%的无 PEW 患者新出现这种情况，每年有 12%-30%的患者从中恢复。存在 PEW 与较高的红细胞生成素抵抗（irEPO）和透析结束时较高的脉搏压相关。在多变量回归模型中，预测 PEW 的临床变量包括水过多、irEPO、细胞内水和细胞外水/细胞内水比值。有 26（21%）名患者死亡。Kaplan-Meier 曲线未显示 PEW 患者与无 PEW 患者的死亡率风险存在差异，但肌肉质量损失与死亡率增加相关。
本观察性研究强调了血液透析患者中 PEW 的高患病率，其具有动态性。只有肌肉质量损失（蛋白质分解代谢增加）这一标准与死亡率增加相关，而根据 ISRNM 分类的其他 PEW 标准与死亡率增加无关。我们还观察到 PEW 患者存在水过多状态。这种水过多状态（由于肌肉损失而占据细胞外水，而总身体水没有增加）不能通过干体重或体重指数来评估。需要进行干预研究以评估预防肌肉减少症是否可以提高生存率。
