Rossing Peter, Rossing Kasper, Gaede Peter, Pedersen Oluf, Parving Hans-Henrik
Steno Diabetes Center, Gentofte, Denmark.
Diabetes Care. 2006 May;29(5):1024-30. doi: 10.2337/diacare.2951024.
The purpose of this study was to assess agreement between glomerular filtration rate (GFR) and the decline in GFR estimated with the Modification of Diet in Renal Disease (MDRD) Study Group equation or the Cockcroft-Gault formula and measured by the plasma clearance of 51Cr-EDTA.
We followed a cohort of 156 microalbuminuric type 2 diabetic patients for 8 years with four measurements of GFR and another cohort of 227 type 2 diabetic patients with overt diabetic nephropathy for 6.5 (range 3-17) years with seven (3-22) measurements of GFR.
For patients with microalbuminuria, mean +/- SD baseline GFR was 117 +/- 24 measured, 92 +/- 20 estimated (MDRD equation), or 103 +/- 24 ml x min(-1) per 1.73 m2 estimated (Cockcroft-Gault formula) (both P < 0.001); 95% limits of agreement were -66.1 to 20.3 (MDRD equation) and -58.7 to 30.7 (Cockcroft-Gault formula). The rate of decline in GFR was 4.1 +/- 4.2 measured, 2.9 +/- 2.8 estimated (MDRD equation), or 3.4 +/- 3.2 ml x min(-1) per 1.73 m2 estimated (Cockcroft-Gault formula) (both P < 0.001). For patients with overt nephropathy, baseline GFR was 84 +/- 30 measured, 73 +/- 24 estimated (MDRD equation), or 81 +/- 28 ml x min(-1) per 1.73 m2 estimated (Cockcroft-Gault formula) (both P < 0.001) with 95% limits of agreement -47 to 25 (MDRD equation) and -39 to 33 (Cockcroft-Gault formula). The rate of decline in GFR was 5.2 +/- 4.1 measured, 4.2 +/- 3.8 estimated (MDRD equation), and 4.6 +/- 4.1 ml x min(-1) per 1.73 m2 estimated (Cockcroft-Gault formula) (both P < 0.001).
Particularly in microalbuminuric (hyperfiltering) patients, GFR is significantly underestimated with wide limits of agreement by the MDRD equation as well as by the Cockcroft-Gault formula. The rate of decline in GFR is also significantly underestimated with both equations. This makes GFR estimations based upon these equations unacceptable for monitoring kidney function in type 2 diabetic patients with incipient and overt diabetic nephropathy.
本研究旨在评估肾小球滤过率（GFR）与采用肾脏病膳食改良（MDRD）研究组方程或Cockcroft - Gault公式估算的GFR下降值之间的一致性，并与通过51Cr - EDTA血浆清除率测得的结果进行比较。
我们对156例微量白蛋白尿型2型糖尿病患者进行了为期8年的随访，期间对GFR进行了4次测量；对另一组227例显性糖尿病肾病的2型糖尿病患者进行了6.5年（范围3 - 17年）的随访，期间对GFR进行了7次（3 - 22次）测量。
对于微量白蛋白尿患者，平均±标准差的基线GFR测量值为117±24，估算值（MDRD方程）为92±20，或估算值（Cockcroft - Gault公式）为103±24 ml·min⁻¹/1.73 m²（两者P < 0.001）；95%一致性界限为 - 66.1至20.3（MDRD方程）和 - 58.7至30.7（Cockcroft - Gault公式）。GFR下降率测量值为4.1±4.2，估算值（MDRD方程）为2.9±2.8，或估算值（Cockcroft - Gault公式）为3.4±3.2 ml·min⁻¹/1.73 m²（两者P < 0.001）。对于显性肾病患者，基线GFR测量值为84±30，估算值（MDRD方程）为73±24，或估算值（Cockcroft - Gault公式）为81±28 ml·min⁻¹/1.73 m²（两者P < 0.001），95%一致性界限为 - 47至25（MDRD方程）和 - 39至33（Cockcroft - Gault公式）。GFR下降率测量值为5.2±4.1，估算值（MDRD方程）为4.2±3.8，估算值（Cockcroft - Gault公式）为4.6±4.1 ml·min⁻¹/1.73 m²（两者P < 0.001）。
特别是在微量白蛋白尿（高滤过）患者中，MDRD方程以及Cockcroft - Gault公式对GFR的估算值显著低估，且一致性界限较宽。两个方程对GFR下降率的估算也显著低估。这使得基于这些方程的GFR估算值对于监测早期和显性糖尿病肾病的2型糖尿病患者的肾功能不可接受。
