Performance of the creatinine and cystatin C-based equations for estimation of GFR in Chinese patients with chronic kidney disease.

Background: Currently, creatinine- or cystatin C-based glomerular filtration rate (GFR) estimation equation has been recommended to assess GFR in CKD patients. However, it is still obscure whether those equations performed consistently outstandingly in Chinese population.
Methods: The equations were validated in a population totaling 632 participants (mean age 61.6 ± 12.3 years). The estimated GFR (eGFR) calculated separately by six equations (C-MDRD, C _cys , C _scr-cys , CKD-EPI _scr , CKD-EPI _cys , and CKD-EPI _scr-cys equations) was compared with the reference GFR (rGFR) measured by the ^99m Tc-DTPA renal dynamic imaging method. Participants were divided into age and rGFR specific subgroups.
Results: CKD-EPI _scr-cys equation had a larger area under receiver operating characteristic curve (ROC ^AUC ) and relative higher sensitivity (79.8 %) and specificity (93 %) to diagnose CKD. CKD-EPI _scr-cys and CKD-EPI _cys equations appeared to be more accurate with higher proportion of eGFR within 30 % of rGFR (P ₃₀ ) value. Those two equations performed as well in older people as in the younger population. The CKD-EPI _scr-cys equation acquired the highest P ₃₀ (80.9 %) in subgroups with rGFR ≥60 mL/min/1.73 m ² , while the CKD-EPI _cys equation yielded the best performance in the rGFR <60 mL/min/1.73 m ² subgroup.
Conclusion: CKD-EPI _scr-cys formula had better capability to accurately evaluate GFR in the participants CKD stages 1-2 in Chinese ethnic. The application of the cystatin C-based equations may be the optimal one for patients of moderately to severely injured GFR. Considering the accuracy in the entire range of participants less ideally, the additional of the Chinese racial factor is assumed to be essential.