Is Serum Cystatin-C a Useful Marker Predicting the Initiation of Maintenance Dialysis?

Choi, Hye Min; Kim, Hye Won; Lee, Jae Won; Hyun, Young Youl; Lee, Sang Won; Lee, Ji Eun; Kwon, Young Joo; Pyo, Heui Jung

Abstract

PURPOSE: Cystatin-C is produced at a constant rate, and has been known to be unaffected by non-renal factors. However, there are limited data on its superiority to serum creatinine as a marker of renal function in ESRD population. The aims of our study were to compare serum cystatin-C and serum creatinine with estimated GFR in ESRD patients at the initiation of dialysis, whether the non-renal factors may influence on serum cystatin-C levels, and whether serum cystatin-C may be a useful marker of the start of dialysis.
METHODS
This study was cross-sectional about 163 ESRD patients. We measured serum cystatin-C and serum creatinine levels at the initiation of dialysis, and determined GFR from 24 hour urine collection [G (Ccr)], Cockcroft-Gault [G (C&G)], and the modification of diet in renal disease [G (MDRD)] formula. We considered age, gender, body weight and diabetic nephropathy as non-renal factors.
RESULTS
The mean serum cystatin-C was 5.0+/-0.9 mg/dL, serum creatinine 11.4+/-5.9 mg/dL, G (Ccr) 5.0+/-2.9 mL/min/1.73m2, G (C&G) 7.5+/-3.1 mL/min/1.73m2, G (MDRD1) 5.7+/-2.9 mL/min/1.73m2, and G (MDRD2) 5.5+/-2.5 mL/min/1.73m2. We found significant correlation between estimated GFR and serum cystatin-C. However, comparing to serum creatinine, serum cystatin-C had no merits in estimating renal function and in predicting urgent hemodialysis. In the multivariate linear regression models, serum cystatin-C had no significant correlation with gender, body weight, and diabetic nephropathy, but decreased with the age.
CONCLUSION
Serum cystatin-C is not superior to serum creatinine for estimating renal function and predicting urgent hemodialysis in ESRD patients. Besides, serum cystatin-C seems to be influenced by non-renal factors, age.