Is the Chronic Kidney Disease Epidemiology Collaboration four-level race equation better than the cystatin C equation?

Abstract

Aim: To evaluate the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) four-level race equation in the assessment of glomerular filtration rate (GFR) in Chinese people with chronic kidney disease (CKD), which was published in 2011, compared with the cystatin C-based GFR estimation equation (CysC GFR) and the combination of CysC and serum creatinine equation (CysC-Scr GFR).

Methods: The CKD-EPI four-level race equation estimated GFR (CKD-EPI GFR) was compared with the CysC GFR and CysC-Scr GFR. Three equations were compared with body surface area (BSA) standardized GFR (sGFR), which was measured by (99m) Tc-DTPA renal dynamic imaging method in 111 CKD cases.

Results: A statistically significant correlation was found between sGFR and CKD-EPI GFR, CysC GFR and CysC-Scr GFR. Three estimated GFR (eGFR) equations of 30% accuracy were 58.6%, 56.8% and 63.5%, respectively. Average deviations of eGFR from sGFR were 2.34, 1.19, and 1.32 (mL/min per 1.73 m(2)) (P > 0.05), respectively. There was no significant deviation in the CKD from stages 1 to 5 in CKD-EPI GFR and CysC-Scr GFR. However, when estimated by CysC GFR, the deviation was increased, with the value of 12.41 mL/min per 1.73 m(2) (P= 0.002) in CKD stage 5.

Conclusion: Our results showed that in a Chinese population with CKD, CKD-EPI GFR, CysC GFR and CysC-Scr GFR of bias and overall accuracy of 30% were very similar. There was little advantage in adding Asian coefficient to modifying the CKD-EPI equation. CysC GFR overestimated GFR in patients with CKD stages 4 and 5.