M1717 Serum Cystatin-C and Creatinine Compared with Standard GFR in Cirrhotic Patients

Abstract

Background: Assessment of glomerular filtration rate (GFR) by common creatinine-based methods is potentially inaccurate in patients with cirrhosis. Cirrhotic patients have several underlying conditions that contribute to falsely low serum creatinine concentrations, even in the presence of moderate to severe renal impairment, therefore creatinine-based methods usually overestimate true GFR in these patients. Cystatin-C is a low molecular weight protein and an endogenous marker of GFR. We compared the accuracy of plasma cystatin-C and creatinine in assessing renal function in cirrhotic patients. Methods: We serially enrolled cirrhotic patients admitted in our ward if they met the inclusion criteria and consented to participate. Child-Pugh (CP) score was calculated for all patients. GFR was calculated using serum creatinine, serum Cystatin-C, and 99mTc-DTPA clearance with the last one serving as the gold standard. The area under curve (AUC) on Receiver-operating characteristic curves were used to compare the diagnostic accuracy of each calculated GFR with that measured by DTPA. Results: Fourty-eight patients were enrolled (32 males, 66.7%). Nine were in class-A, 20 in class-B and 19 in class-C of CP score. Cystatin-C did not perform well in predicting the true GFR, while serum creatinine performed relatively accurate at GFR 20 a GFR<80 could also be predicted by serum creatinine (ROC curve AUC=0.739, p=0.034). Serum creatinie could also predict GFR<80ml/min in patients with CP class A & B (ROC curve AUC=0.795, p=0.01), but not in patients with CP class C. Conclusion: Neither serum creatinine nor Cystatin-C are good predictors of GFR in cirrhostic patients, although serum creatinine seems to perform better in selected subgroups.