Comparison of prediction equations to estimate glomerular filtration rate in Chinese patients with chronic kidney disease

Aim: We sought to evaluate the applicability of formulae based on serum creatinine (SC) levels in Chinese patients with chronic kidney disease (CKD). Materials and methods: Three hundred and twenty-seven patients with CKD who had undergone ^99mTc-DTPA glomerular filtration rate (GFR) estimation were enrolled. The Cockcroft-Gault equation, SC-reciprocal equation, Gate equation, Hull equation, Jelliffe-1973 equation, Jelliffe-1971 equation, Mawer equation, Bjornsson equation, reexpressed 6-variable MDRD equation and reexpressed 4-variable MDRD equation were compared. Using the ^99mTc-DTPA GFR as the standard GFR (sGFR), the accuracy of estimated GFR was compared with sGFR in various stages of CKD. Results: Median per cents of the absolute difference ranged from 28.16% to 39.39%, accuracy with a deviation less than 30% ranging from 39.4% to 53.5%, accuracy with a deviation less than 50% ranging from 63.0% to 80.7%. None of the equations had accuracy up to the 70% level with a deviation less than 30% from sGFR. Bland-Altman analysis demonstrated that mean difference ranged from -2.42 to 16.39mL/min/1.73m², whereas precision ranged from 82.66 to 106.15mL/min/1.73m². However, the agreement limits of all the equations exceeded the prior acceptable tolerances defined as 60mL/min/1.73m². Linear regression showed that the slopes of regression line ranged from 0.37 to 0.54 and intercepts ranged from -12.10 to 3.86. When the overall performance as well as bias and accuracy were compared in different stages of CKD, GFR estimated by Jelliffe-1973 equation, Cockcroft-Gault equation and Bjornsson equation showed promising results. Conclusion: When SC was measured by the enzymatic method, GFR estimation equations showed great bias in Chinese CKD patients. At present, the Jelliffe-1973 equation and Cockcroft-Gault equation may be more accurate in the Chinese ethnic group.