Division of Pediatric Nephrology, University of Miami/Holtz Children's Hospital, Miami, FL.
Division of Pediatric Nephrology, University of Miami/Holtz Children's Hospital, Miami, FL.
J Pediatr. 2014 May;164(5):1026-1031.e2. doi: 10.1016/j.jpeds.2014.01.044. Epub 2014 Mar 5.
To distinguish between cystatin C (CysC) and creatinine (Cr) as markers of estimated glomerular filtration rate (eGFR) in preterm infants and to correlate eGFR with total kidney volume (TKV) as a surrogate of nephron mass.
Sixty preterm (<37 weeks' gestational age [GA]) and 40 term infants were enrolled at birth. Serum Cr and CysC levels were assessed during the first week of life. Renal ultrasounds were performed to assess kidney dimensions with calculation of the TKV as a surrogate of nephron mass. Six equations derived from reference inulin, iohexol, and iothalamate clearance studies were used to calculate eGFR. Multiple regression analysis was applied to assess the relative impact of neonatal measures on eGFR, including TKV, GA, and mean arterial pressure (MAP).
Renal lengths correlated with GA and were within the reference values for intrauterine measurements. Estimation equations for glomerular filtration rate (GFR) based on Cr, CysC, and combined CysC + Cr demonstrated that Cr-based equations consistently underestimated GFR, whereas CysC and combined equations were more consistent with referenced inulin clearance studies. Term infants demonstrated significantly better eGFR than preterm infants. TKV, GA, and MAP correlated positively with eGFR, although only MAP and GA remained significant when adjusted for other covariates.
Primary determinants of eGFR in preterm infants are GA and MAP. The CysC level is a superior biomarker to serum Cr in the assessment of GFR in premature infants.
区分胱抑素 C（CysC）和肌酐（Cr）作为早产儿估算肾小球滤过率（eGFR）的标志物，并将 eGFR 与总肾体积（TKV）相关联，作为肾小球滤过率的替代指标。
本研究纳入了 60 名早产儿（<37 周胎龄[GA]）和 40 名足月儿。在出生后的第一周内检测血清 Cr 和 CysC 水平。进行肾脏超声检查以评估肾脏尺寸，并计算 TKV 作为肾小球滤过率的替代指标。使用来自参考物质菊粉、碘海醇和碘酞酸盐清除研究的 6 个方程来计算 eGFR。应用多元回归分析评估新生儿指标对 eGFR 的相对影响，包括 TKV、GA 和平均动脉压（MAP）。
肾脏长度与 GA 相关，并且在宫内测量的参考值范围内。基于 Cr、CysC 和 CysC+Cr 组合的肾小球滤过率（GFR）估计方程表明，Cr 基础方程始终低估了 GFR，而 CysC 和组合方程与参考的菊粉清除研究更为一致。足月儿的 eGFR 明显优于早产儿。TKV、GA 和 MAP 与 eGFR 呈正相关，但当调整其他协变量时，只有 MAP 和 GA 仍然具有统计学意义。
早产儿 eGFR 的主要决定因素是 GA 和 MAP。在评估早产儿 GFR 时，CysC 水平优于血清 Cr。
