Ng Derek K, Schwartz George J, Warady Bradley A, Furth Susan L, Muñoz Alvaro
Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
University of Rochester Medical Center, Rochester, NY.
Am J Kidney Dis. 2017 Sep;70(3):397-405. doi: 10.1053/j.ajkd.2017.03.019. Epub 2017 May 24.
2 valid and reliable estimated glomerular filtration rate (GFR) equations for the pediatric population have been developed from directly measured GFR data in the Chronic Kidney Disease in Children (CKiD) cohort: the full CKiD and bedside CKiD equations. Although adult GFR estimating equations replicate relationships of measured GFR with biomarkers, it is unclear whether similar patterns exist among children and adolescents with chronic kidney disease (CKD).
Prospective cohort study in children and adolescents.
SETTINGS & PARTICIPANTS: 730 participants contributed 1,539 study visits.
Measured GFR by plasma iohexol disappearance (mGFR), estimated GFR by the full CKiD equation (eGFR; based on serum creatinine, cystatin C, serum urea nitrogen, height, and sex), and estimated GFR by the bedside CKiD equation (eGFR; calculated as 41.3 × height [m]/serum creatinine [mg/dL]) were predictors of CKD-related biomarkers. Deviations of mGFR from eGFR and deviations of eGFR from eGFR from linear regressions (ie, residuals) were included in bivariate analyses.
OUTCOMES & MEASUREMENTS: CKD-related biomarkers included values for urine protein-creatinine ratio, blood hemoglobin, serum phosphate, bicarbonate, potassium, systolic and diastolic blood pressure z scores, and height z scores.
The median age of 730 participants with CKD was 12.5 years, with median mGFR, eGFR, and eGFR of 51.8, 54.0, and 53.2mL/min/1.73m, respectively. eGFR demonstrated as strong or stronger associations with CKD-related biomarkers than mGFR; eGFR associations were significantly attenuated (ie, closer to the null). Residual information in mGFR did not substantially increase explained variability. eGFR estimated faster GFR decline relative to mGFR and eGFR.
Simple linear summaries of biomarkers may not capture nonlinear associations.
eGFR closely approximated mGFR to describe relationships with CKD-severity indicators and progression in this pediatric CKD population. eGFR offered similar inferences, but associations were attenuated and rate of progression was overestimated. The eGFR equation from 2012 is preferred for pediatric research purposes.
基于儿童慢性肾脏病（CKiD）队列中直接测量的肾小球滤过率（GFR）数据，已开发出2个适用于儿科人群的有效且可靠的GFR估算方程：完整CKiD方程和床边CKiD方程。尽管成人GFR估算方程可重现测量的GFR与生物标志物之间的关系，但尚不清楚慢性肾脏病（CKD）患儿及青少年中是否存在类似模式。
对儿童和青少年进行的前瞻性队列研究。
730名参与者进行了1539次研究访视。
通过血浆碘海醇清除率测量的GFR（mGFR）、完整CKiD方程估算的GFR（eGFR；基于血清肌酐、胱抑素C、血清尿素氮、身高和性别）以及床边CKiD方程估算的GFR（eGFR；计算方法为41.3×身高[m]/血清肌酐[mg/dL]）是CKD相关生物标志物的预测因素。mGFR与eGFR的偏差以及线性回归中eGFR与eGFR的偏差（即残差）纳入双变量分析。
CKD相关生物标志物包括尿蛋白肌酐比值、血红蛋白、血清磷酸盐、碳酸氢盐、钾、收缩压和舒张压z评分以及身高z评分。
730例CKD参与者的中位年龄为12.5岁，mGFR、eGFR和eGFR的中位数分别为51.8、54.0和53.2mL/min/1.73m²。与mGFR相比，eGFR与CKD相关生物标志物的关联显示出同等强度或更强；eGFR的关联显著减弱（即更接近无效值）。mGFR中的残差信息并未显著增加可解释的变异性。相对于mGFR和eGFR，eGFR估算的GFR下降更快。
生物标志物的简单线性总结可能无法捕捉非线性关联。
在该儿科CKD人群中，eGFR与mGFR非常接近，可用于描述与CKD严重程度指标及病情进展的关系。eGFR提供了类似的推断，但关联减弱且进展速度被高估。2012年的eGFR方程更适合儿科研究目的。
