Abstract:

ABSTRACT    Objective：Cystatin C （CysC）has been recognized as an alternative marker to serum creatinine (SCr). However, whether CysC would be superior to SCr in Chinese population, especially in elderly, has been rarely compared, referring to glomerular filtration rate (GFR). The objective of this study was to assess diagnostic significance of serum CysC in evaluation of kidney function for elderly Chinese. Methodology：99mTc-DTPA clearance was measured as reference GFR (rGFR). SCr was determined using enzymatic method and CysC was assayed by particle-enhanced immunoturbidimetry assay. Pearson correlation analysis was applied to explore the association between kidney function markers and rGFR. Area under receiver operating characteristic curve (ROCAUC) was measured to compare diagnostic accuracy of the two markers. The detection rate of CKD in mild impaired kidney function stage was analyzed to compare the sensitivity of markers. Linear regression analysis was applied to clarify the influence factors of the markers. Results: A total of three hundred and eighteen Chinese participants (18~95y, mean age 52.95 ± 17.13yr) were enrolled. There was significantly better diagnostic accuracy and more sensitivity with CysC than that with SCr: relationship with GFR (-0.807 vs -0.650), AUCROC (0.867 vs 0.772) and sensitivity (0.88 vs. 0.56) for predicting CKD or the detection rate of CKD patients in CKD stage 2 (4.83% vs 0.69%) and stage 3 (72.58% vs 46.77%). Moreover, these merits were more distinctly observed in elderly participants. Linear regression analysis manifested SCr was affected by gender (P < 0.05); however, CysC, in conformity with GFR, was out of this influence. Conclusions: CysC may accurately predict GFR. In comparison with SCr, CysC could be more sensitive and reliable to screen CKD patients with less influence factors. Furthermore, this superiority of CysC may be more remarkable when applied for elderly participants.

Key words: Key Words  , glomerular filtration rate  , Cystatin C   , creatinine   , elderly