Cystatin C is a biomarker for predicting acute kidney injury in patients with acute-on-chronic liver failure

Abstract

Aim: To investigate serum cystatin C level as an early biomarker for predicting acute kidney injury (AKI) in patients with acute-on-chronic liver failure (ACLF).

Methods: Fifty-six consecutive patients with hepatitis B virus-related ACLF who had normal serum creatinine (Cr) level (< 1.2 mg/dL in men, or < 1.1 mg/dL in women) were enrolled in the Liver Failure Treatment and Research Center of Beijing 302 Hospital between August 2011 and October 2012. Thirty patients with chronic hepatitis B (CHB) and 30 healthy controls in the same study period were also included. Measurement of serum cystatin C (CysC) was performed by a particle-enhanced immunonephelometry assay using the BN Prospec nephelometer system. The ACLF patients were followed during their hospitalization period.

Results: In the ACLF group, serum level of CysC was 1.1 ± 0.4 mg/L, which was significantly higher (P < 0.01) than those in the healthy controls (0.6 ± 0.3 mg/L) and CHB patients (0.7 ± 0.2 mg/L). During the hospitalization period, eight ACLF patients developed AKI. Logistic regression analysis indicated that CysC level was an independent risk factor for AKI development (odds ratio = 1.8; 95%CI: 1.4-2.3, P = 0.021). The cutoff value of serum CysC for prediction of AKI in ACLF patients was 1.21 mg/L. The baseline CysC-based estimated glomerular filtration rate (eGFR(CysC)) was significantly lower than the creatinine-based eGFR (eGFR(CG) and eGFR(MDRD)) in ACLF patients with AKI, suggesting that baseline eGFR(CysC) represented early renal function in ACLF patients while the Cr levels were still within the normal ranges.

Conclusion: Serum CysC provides early prediction of renal dysfunction in ACLF patients with a normal serum Cr level.

Keywords: Acute kidney injury; Acute-on-chronic liver failure; Creatinine; Cystatin C; Prediction.

Figure 1

Scatter plots. A: Serum cystatin C (CysC) level vs model for end-stage liver disease (MELD) score; B: Serum CysC level vs serum creatinine (Cr) level.

Figure 2

Receiver operating characteristic curve. Receiver operating characteristic curve analysis was performed to compare the efficacy of serum cystatin C, creatinine, blood urea nitrogen (BUN) and serum sodium level in predicting acute kidney injury.

Figure 3

Performance of four equations for measuring estimated glomerular filtration rate in patients with acute-on-chronic liver failure. A: Baseline estimated glomerular filtration rate (eGFR) between patients with or without acute kidney injury (AKI); B: Comparison of four eGFR values in patients with AKI. eGFR_CG: The Cockcroft and Gault formula; eGFR_MDRD: The modification of the diet in renal disease equation; eGFR_CysC-1: Cystatin C-based Hoek estimate; eGFR_CysC-2: Chronic Kidney Disease Epidemiology Collaboration cystatin C equation. ^bP < 0.01 vs GFRc_ysC in patients without AKI; ^dP < 0.01 vs e-GFR_CG, and e-GFR_MDRD in patients with AKI.