Division of Nuclear Medicine, Department of Medical Imaging and Clinical Oncology, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Hospital, Cape Town, South Africa.
S Afr Med J. 2020 Feb 26;110(3):229-234. doi: 10.7196/SAMJ.2020.v110i3.13995.
The Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are two commonly used formulae to estimate glomerular filtration rate (GFR) in adults. The CKD-EPI equation is recommended in current international and local guidelines for the diagnosis and management of chronic kidney disease (CKD), unless an alternative equation has been shown to have superior accuracy. Validation and comparison of the equations in local populations are therefore required. Previous studies have reported on the accuracy of these prediction equations in black South Africans and those of Indian ancestry.
To evaluate the MDRD and CKD-EPI equations in South African (SA) adults of mixed ancestry.
In all participants, GFR was measured (mGFR) from plasma clearance of 99mTc-diethylenetetraaminepenta-acetic acid (99mTc-DTPA), using a standardised technique. Serum creatinine assays were isotope dilution mass spectrometry traceable. GFR was estimated (eGFR) using the MDRD and CKD-EPI equations, with and without the black ethnicity factor. The agreement, bias, precision and accuracy of each equation was determined.
Eighty adults were included (30 male, median age 39 years, median GFR 59 mL/min/1.73 m2). Sixty-eight had a diagnosis of CKD, 10 were potential kidney donors, and 2 were healthy volunteers. Both equations, without the black ethnicity factor, had good agreement with measured GFR. The equations tended to overestimate GFR, with bias of 1.6 and 7.9 mL/min/1.73 m2 for the MDRD and CKD-EPI equations, respectively. The interquartile ranges of the differences were 15.9 and 20.2 mL/min/1.73 m2, and as a measure of accuracy, the percentages of estimates that fell within 30% of the mGFR (P30) were 80% and 72.5% (p=0.18). For identification of individuals with a GFR <60 mL/min/1.73 m2, the sensitivity of MDRD eGFR was 97.3% and that of CKD-EPI eGFR was 97.1%.
The MDRD and CKD-EPI equations have shown satisfactory and comparable performance in this SA mixed-ancestry adult population, with the MDRD equation marginally less biased than the CKD-EPI.
改良肾脏病饮食研究（MDRD）和慢性肾脏病流行病学合作（CKD-EPI）公式是两种常用于估算成人肾小球滤过率（GFR）的公式。目前的国际和本地指南推荐使用 CKD-EPI 公式来诊断和管理慢性肾脏病（CKD），除非替代公式已被证明具有更高的准确性。因此，需要在当地人群中验证和比较这些公式。以前的研究已经报告了这些预测公式在南非黑人以及印度裔人群中的准确性。
评估改良肾脏病饮食研究（MDRD）和慢性肾脏病流行病学合作（CKD-EPI）公式在南非（SA）混合血统成年人中的准确性。
在所有参与者中，使用标准技术从 99mTc-二乙三胺五乙酸（99mTc-DTPA）的血浆清除率测量肾小球滤过率（mGFR）。血清肌酐检测采用同位素稀释质谱法溯源。使用 MDRD 和 CKD-EPI 公式，不包括黑人种族因素，估算肾小球滤过率（eGFR）。确定每个公式的一致性、偏差、精度和准确性。
共纳入 80 名成年人（30 名男性，中位年龄 39 岁，中位肾小球滤过率 59 mL/min/1.73 m2）。68 人患有 CKD，10 人是潜在的肾脏供体，2 人是健康志愿者。不包括黑人种族因素在内的两个公式均与实测 GFR 具有良好的一致性。这些公式往往高估了 GFR，MDRD 和 CKD-EPI 公式的偏差分别为 1.6 和 7.9 mL/min/1.73 m2。差异的四分位间距分别为 15.9 和 20.2 mL/min/1.73 m2，作为准确性的衡量标准，估计值中落在 mGFR 的 30%以内（P30）的百分比分别为 80%和 72.5%（p=0.18）。对于识别肾小球滤过率 <60 mL/min/1.73 m2 的个体，MDRD eGFR 的敏感性为 97.3%，CKD-EPI eGFR 的敏感性为 97.1%。
在南非混合血统成年人中，MDRD 和 CKD-EPI 公式表现出令人满意且相当的性能，MDRD 公式的偏差略小于 CKD-EPI 公式。
