Modified Glomerular Filtration Rate Estimating Equation for Chinese Patients with Chronic Kidney Disease

TLDR

The MDRD equations are widely used to estimate GFR in CKD, but prior studies have shown they require adjustment for Chinese patients. This study aimed to develop and validate modified MDRD equations based on Chinese CKD data and compare their diagnostic performance across CKD stages. Using 684 Chinese CKD patients from nine regions, 454 were used to train the models and 230 to test them with Tc‑DTPA plasma clearance as the reference, and the equations were modified by adding a Chinese racial factor and by re‑estimating coefficients via multiple linear regression. The modified equations demonstrated markedly better bias, precision, and accuracy, with over 75 % of eGFR values within 30 % of the reference, and provided clear advantages across CKD stages, making them suitable for clinical use in Chinese patients.

Abstract

The Modification of Diet in Renal Disease (MDRD) equations provide a rapid method of assessing GFR in patients with chronic kidney disease (CKD). However, previous research indicated that modification of these equations is necessary for application in Chinese patients with CKD. The objective of this study was to modify MDRD equations on the basis of the data from the Chinese CKD population and compare the diagnostic performance of the modified MDRD equations with that of the original MDRD equations across CKD stages in a multicenter, cross-sectional study of GFR estimation from plasma creatinine, demographic data, and clinical characteristics. A total of 684 adult patients with CKD, from nine geographic regions of China were selected. A random sample of 454 of these patients were included in the training sample set, and the remaining 230 patients were included in the testing sample set. With the use of the dual plasma sampling (99m)Tc-DTPA plasma clearance method as a reference for GFR measurement, the original MDRD equations were modified by two methods: First, by adding a racial factor for Chinese in the original MDRD equations, and, second, by applying multiple linear regression to the training sample and modifying the coefficient that is associated with each variable in the original MDRD equations and then validating in the testing sample and comparing it with the original MDRD equations. All modified MDRD equations showed significant performance improvement in bias, precision, and accuracy compared with the original MDRD equations, and the percentage of estimated GFR that did not deviate >30% from the reference GFR was >75%. The modified MDRD equations that were based on the Chinese patients with CKD offered significant advantages in different CKD stages and could be applied in clinical practice, at least in Chinese patients with CKD.