Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden
Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden
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DOI：
10.1515/cclm-2014-0578
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发表时间：
2015-02-01
影响因子：
6.8
通讯作者：
Nyman, Ulf
中科院分区：
文献类型：
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作者：
Bjork, Jonas;Grubb, Anders;Nyman, Ulf
背景：最近建立的国际胱抑素C校准仪使非实验室特异性肾小球滤过率(GFR)估计(EGFR)方程的建立成为可能。这项研究比较了修正的Lund-Malmo肌酐和CAPA胱抑素C方程的算术平均值(Mean(LM-REV+CAPA))、慢性肾脏疾病流行病学协作方程(CKD-EPI)的算术平均值(Mean(CKD-EPI))、和CKD-EPI复合方程(CKD-EPICREA+CySC)和相应的单标志物方程，使用国际标准化的胱抑素C和肌酐校准器。方法：研究包括1112名瑞典成年患者的1200次检查，这些患者2008-2010年通过血浆碘己醇清除法(中位数51mL/min/1.73m(2))测量肾小球滤过率(MGFR)。比较偏倚、精密度(四分位数范围)和准确度(估计值占mGFR的+/-30%；P-30)。结果：联合标记方程无偏倚，比单标记方程具有更高的精密度和准确度。MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC的总体结果为：中位偏差-2.2%/-0.5%/-1.6%，IQR9.2/9.2/8.8mL/min/1.73m(2)，P-3091.3%/91.0%/91.1%。P-30数据比单标记方程高出约7-14个百分点。组合方程在mGFR、年龄和BMI区间也有更稳定的表现，通常成年人的P-30和GT；=90%，从不=90%。在临床环境中报告单标记方程和组合标记方程的估计使基于单标记方程之间的一致性来评估组合方程的有效性成为可能。
Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine.Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m(2)). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates +/- 30% of mGFR; P-30) were compared.Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m(2), and P-30 91.3%/91.0%/91.1%. The P-30 figures were about 7-14 -percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P-30 >= 90% and never = 90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations.