Diagnostic value of serum cystatin C for evaluation of hepatorenal syndrome

Background: The evaluation of renal function in patients with decompensated cirrhosis is important for prognosis, dosage assessment of potentially nep hrotoxic drugs and recognition of changes in glomerular filtration rate (GF R) to decide paracentesis and diuretic therapy. Patients with many differen t disorders of hepatic function can present with various abnormalities of r enal function in the absence of other known causes of renal failure which h as been called hepatorenal syndrome (HRS), Some reports have pointed out th at serum creatinine levels frequently failed to rise above normal levels ev en when glomerular filtration rate (GFR) is very low in cirrhotic patients with hepatorenal syndrome. The aim of this study was to determine if estima tion of serum cystatin C could replace creatinine clearance in routine GFR determinations for patients with cirrhosis. Methods: Serum cystatin C, crea tinine clearance (Clcr), and 99mTc-DTPA clearance were determined in 26 pat ients with cirrhosis. According to Child-Pugh's classification, 21 patients were in group C and 5 were in Group B. Results: Pearson correlation analys es showed that correlation between serum cystatin C and 99mTc-DTPA clearanc e was r = -0.522, p = 0.006, between serum creatinine and 99mTc-DTPA was r = -0.373, p = 0.06. The results of our study demonstrated that neither seru m creatinine nor creatinine clearance (Clcr) were good indicators of hepato renal syndrome because the mean value for Clcr was found to be higher than Tc-DTPA clearance, and there was no correlation between these two parameter s (r = 0.059). Additionally, the mean value of serum creatinine was found t o be within the normal range, whereas the mean DTPA clearance level was low er than normal range. Conclusions: This finding could be explained by the f act that cirrhotic patients with poor nutrition may have decreased protein intake, low muscle mass and lack of converting capacity of creatine to crea tinine. Thus, we suggest that serum cystatin C assay, which has good analyt ical performance, could replace or at least be added to creatinine measurem ent for GFR assessment in patients with cirrhosis. (C) 2001 Elsevier Scienc e B.V. All rights reserved.