Evaluation of serum creatinine- and cystatin C-based equations for the estimation of glomerular filtration rate in a Chinese population

Abstract

Objective. This study aimed to evaluate the applicability of a selection of glomerular filtration rate (GFR) estimating equations based on serum creatinine (SCr) and serum cystatin C in a Chinese population. Material and methods. Estimated GFR values from 10 equations were compared with reference GFR (rGFR) from the ^99mTc-DTPA renal dynamic imaging method. The study enrolled 569 Chinese participants (41.5% women, 53.5 ± 16.9 years, range 19–92 years), with mean rGFR 74.80 ± 26.10 (range 9.8–146.8 ml/min/1.73 m²). Results. Bland–Altman analysis illustrated that the 95% agreement limits of all the equations surpassed the acceptable tolerance (<60 ml/min/1.73 m²), of which the MacIsaac equation was the closest one, reaching 71.7 ml/min/1.73 m². Linear regression analysis also demonstrated a consistent result. When assessed in all participants, the accuracy of the six equations reached and exceeded the acceptable level (≥70%), of which the Shanghai and MacIsaac equations gained more accuracy than others. When compared in subgroups, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), MacIsaac and Cockcroft–Gault (CG) equations were optimal for rGFR stages ≥ 90 ml/min/1.73 m², 30–89 ml/min/1.73 m² and < 30 ml/min/1.73 m², respectively. Conclusion. The results demonstrated that further improvement is needed for the selected 10 equations. Not all the cystatin C equations were superior to SCr equations. They have their own applicability at various GFR levels. At present, the CKD-EPI, MacIsaac and CG equations may be applied to evaluate GFR in normal, mild to moderate and severe kidney function, respectively.

Key Words::

• Chinese
• cystatin C
• glomerular filtration rate
• prediction equations
• serum creatinine

Acknowledgements

This work was supported by the Scientific Research Program of the Health Department of Jiangsu Province H200902 and XK16200903 and the blue project fund 2010 of Jiangsu province. We are also grateful to the participants for their good cooperation.

Declaration of interest : The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.