González-Rinne Ana, Luis-Lima Sergio, Escamilla Beatriz, Negrín-Mena Natalia, Ramírez Ana, Morales Adelaida, Vega Nicanor, García Patricia, Cabello Elisa, Marrero-Miranda Domingo, Aldea-Perona Ana, Alvarez Alejandra, Abad María Del Carmen, Pérez-Tamajón Lourdes, González-Rinne Federico, González-Delgado Alejandra, Díaz Martín Laura, Jiménez-Sosa Alejandro, Torres Armando, Porrini Esteban
Nephrology Department, Hospital Universitario de Canarias, Tenerife, Spain.
Research Unit-UCICEC, Hospital Universitario de Canarias, Tenerife, Spain.
Clin Kidney J. 2019 Mar 18;12(5):748-755. doi: 10.1093/ckj/sfz012. eCollection 2019 Oct.
Reliable determination of glomerular filtration rate (GFR) is crucial in the evaluation of living kidney donors. Although some guidelines recommend the use of measured GFR (mGFR), many centres still rely on estimated GFR (eGFR) obtained through equations or 24-h creatinine clearance. However, eGFR is neither accurate nor precise in reflecting real renal function. We analysed the impact of eGFR errors on evaluation and decision making regarding potential donors.
We evaluated 103 consecutive living donors who underwent mGFR via iohexol plasma clearance and eGFR by 51 creatinine- and/or cystatin C-based equations. The cut-off for living donation in our centre is GFR > 80 mL/min for donors >35 years of age or 90 mL/min for those <35 years of age. We analysed the misclassification of donors based on the cut-off for donation-based eGFR.
Ninety-three subjects (90.3%) had mGFR values above (donors) and 10 [9.7% (95% confidence interval 5.4-17)] below (non-donors) the cut-off. In non-donors, most of the equations gave eGFR values above the cut-off, so donation would have been allowed based on eGFR. All non-donors were female with reduced weight, height and body surface. In donors, up to 32 cases showed eGFR below the cut-off, while mGFR was actually higher. Therefore an important number of donors would not have donated based on eGFR alone.
The misclassification of donors around the cut-off for donation is very common with eGFR, making eGFR unreliable for the evaluation of living kidney donors. Whenever possible, mGFR should be implemented in this setting.
准确测定肾小球滤过率（GFR）对于活体肾供体的评估至关重要。尽管一些指南推荐使用实测GFR（mGFR），但许多中心仍依赖通过公式或24小时肌酐清除率获得的估算GFR（eGFR）。然而，eGFR在反映真实肾功能方面既不准确也不精确。我们分析了eGFR误差对潜在供体评估和决策的影响。
我们评估了103例连续的活体供体，这些供体通过碘海醇血浆清除率测定mGFR，并通过51种基于肌酐和/或胱抑素C的公式测定eGFR。我们中心活体肾捐献的临界值为年龄大于35岁的供体GFR>80 mL/min，年龄小于35岁的供体GFR>90 mL/min。我们根据基于捐献的eGFR临界值分析了供体的错误分类情况。
93名受试者（90.3%）的mGFR值高于临界值（供体），10名受试者[9.7%（95%置信区间5.4 - 17）]的mGFR值低于临界值（非供体）。在非供体中，大多数公式得出的eGFR值高于临界值，因此基于eGFR本应允许捐献。所有非供体均为女性，体重、身高和体表面积均降低。在供体中，多达32例显示eGFR低于临界值，而实际mGFR更高。因此，相当数量的供体仅基于eGFR不会进行捐献。
eGFR在捐献临界值附近对供体的错误分类非常常见，这使得eGFR在活体肾供体评估中不可靠。在这种情况下，应尽可能采用mGFR。
