Arbor Research Collaborative for Health, Ann Arbor, Michigan, USA.
Clin J Am Soc Nephrol. 2011 Oct;6(10):2452-61. doi: 10.2215/CJN.00710111. Epub 2011 Aug 25.
Measurement of C-reactive protein (CRP) levels remains uncommon in North America, although it is now routine in many countries. Using Dialysis Outcomes and Practice Patterns Study data, our primary aim was to evaluate the value of CRP for predicting mortality when measured along with other common inflammatory biomarkers.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We studied 5061 prevalent hemodialysis patients from 2005 to 2008 in 140 facilities routinely measuring CRP in 10 countries. The association of CRP with mortality was evaluated using Cox regression. Prediction of 1-year mortality was assessed in logistic regression models with differing adjustment variables.
Median baseline CRP was lower in Japan (1.0 mg/L) than other countries (6.0 mg/L). CRP was positively, monotonically associated with mortality. No threshold below which mortality rate leveled off was identified. In prediction models, CRP performance was comparable with albumin and exceeded ferritin and white blood cell (WBC) count based on measures of model discrimination (c-statistics, net reclassification improvement [NRI]) and global model fit (generalized R(2)). The primary analysis included age, gender, diabetes, catheter use, and the four inflammatory markers (omitting one at a time). Specifying NRI ≥5% as appropriate reclassification of predicted mortality risk, NRI for CRP was 12.8% compared with 10.3% for albumin, 0.8% for ferritin, and <0.1% for WBC.
These findings demonstrate the value of measuring CRP in addition to standard inflammatory biomarkers to improve mortality prediction in hemodialysis patients. Future studies are indicated to identify interventions that lower CRP and to identify whether they improve clinical outcomes.
尽管 C 反应蛋白（CRP）的测量在北美的应用并不常见，但在许多国家已成为常规。利用 Dialysis Outcomes and Practice Patterns Study 数据，我们的主要目的是评估 CRP 与其他常见炎症生物标志物联合检测时，预测死亡率的价值。
设计、地点、参与者和测量方法：我们研究了来自 10 个国家 140 个常规检测 CRP 的透析中心的 5061 例 2005 至 2008 年期间的维持性血液透析患者。使用 Cox 回归评估 CRP 与死亡率的相关性。使用不同调整变量的逻辑回归模型评估 1 年死亡率的预测。
基线 CRP 的中位数在日本（1.0mg/L）低于其他国家（6.0mg/L）。CRP 与死亡率呈正相关，且呈单调递增关系。未发现死亡率趋于平稳的 CRP 截断值。在预测模型中，CRP 的性能与白蛋白相当，且优于铁蛋白和白细胞计数（WBC），基于模型区分度（c 统计量、净重新分类改善[NRI]）和整体模型拟合（广义 R2）的测量。主要分析纳入年龄、性别、糖尿病、导管使用以及 4 种炎症标志物（每次排除一个）。将 NRI≥5%作为预测死亡率风险的适当重新分类标准，CRP 的 NRI 为 12.8%，白蛋白为 10.3%，铁蛋白为 0.8%，WBC 为<0.1%。
这些发现表明，除了标准炎症生物标志物外，还需要测量 CRP 以提高血液透析患者的死亡率预测价值。未来的研究需要确定降低 CRP 的干预措施，并确定这些干预措施是否能改善临床结局。
