estimating glomerular filtration rates in elderly chinese patients with chronic kidney disease: performance of six modified formulae developed in asian populations

Xun Liu,1,2,* Haixia Xu,3,* Zebin Zheng,4,5,* Cheng Wang,1 Cailian Cheng,1 Chenggang Shi,1 Yihong Gong,4,5 Ming Li,1 Tanqi Lou1 1Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 2College of Biology Engineering, South China University of Technology, 3Division of Endocrinology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China; 4Department of Biomedical Engineering, School of Engineering, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China; 5Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instruments, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China *These authors contributed equally to this work Objectives: The aim of the present study was to evaluate modified glomerular filtration rate (GFR) prediction formulae in an elderly Chinese population with chronic kidney disease (CKD). Methods: A total of 378 elderly Chinese patients with CKD were enrolled. The GFR was estimated with six modified GFR prediction formulae. The performances of the estimated GFRs were compared with those of the standard GFRs measured by technetium-99m diethylenetraminepentaacetic acid. Results: Biases were similar for Chinese formula 1, the Asian formula, and Chinese formula 2 (median difference, 2.22 mL/min/1.73 m2 and 2.59 mL/min/1.73 m2 for Chinese formula 1 and the Asian formula, respectively, versus (vs) 3.69 mL/min/1.73 m2 for Chinese formula 2 [P = 0.298 and P = 0.913, respectively]). Precision was improved with the Japanese formula (interquartile range of the difference, 3.14 mL/min/1.73 m2 of the Japanese formula versus 15.53–23.06 mL/min/1.73 m2 of the other formulae. The accuracy of Chinese formula 2 was the highest (30% accuracy, 59.3% vs range 37.8–54.0% [P < 0.05 for all comparisons]). However, none of the modified formulae surpassed the acceptable tolerance (>70%), and the GFR category misclassification rates for all the formulae exceeded 50%. Conclusion: Our findings suggest that all six modified formulae developed in Asian populations may show great bias in elderly Chinese patients with CKD. Also, our study suggests the need for uniform measures for the assessment of CKD in the elderly to guarantee better sensitivity and specificity. Keywords: formula, CKD, Asian, GFR