A comparison of different estimation equations for glomerular filtration rate in Chinese diabetic patients

Abstract To compare the accuracy and precision of C-G equation, simplified MDRD equation, the Chinese equation, Ruijin equation, and CKD-EPI equation for estimating glomerular filtration rate (GFR) in Chinese diabetic patients. Diabetic patients visiting the West China Hospital (both outpatient and inpatient departments) of Sichuan University who were older than 18 years old were enrolled in this study. Their general health and clinical characteristics were recorded. The GFR of those patients were evaluated by 99mTc-DTPA dynamic renal imaging (rGFR). We compared the accuracy and precision of C-G equation, simplified MDRD equation, the Chinese equation, Ruijin equation and CKD-EPI equation for estimating GFR (eGFR). We also tested whether levels of GFR, plasma creatinine (Scr) and fasting plasma glucose (FPG) influenced the accuracy and precision of the equations. 217 diabetic patients (139 males and 78 females) were enrolled in this study. Compared with rGFR, C-G equation underestimated GFR slightly; whereas simplified MDRD equation, the Chinese equation, Ruijin equation and CKD-EPI equation overestimated GFR. Ruijin equation had the best accuracy and precision in all the equations, followed by CKD-EPI equation. When patients had lower than 133 microml/L Scr, Ruijin equation had the best accuracy and precision. When patients had 133-177 micromol/L Scr, CKD-EPI equation had the best accuracy and precision. When patients had higher than 177 micromol/L Scr, there was no obvious difference in accuracy and precision among the equations. Regardless of the level of FPG, Ruijin equation had the best accuracy and precision in all the equations. Ruijin equation is the best equation for estimating GFR, followed by CKD-EPI equation.