Conventional creatinine-based glomerular filtration rate (GFR) equations are 
insufficiently accurate for estimating GFR in cirrhosis. The Chronic Kidney 
Disease Epidemiology Collaboration (CKD-EPI) recently proposed an equation to 
estimate GFR in subjects without cirrhosis using both serum creatinine and 
cystatin C levels. Performance of the new CKD-EPI creatinine-cystatin C equation 
(2012) was superior to previous creatinine- or cystatin C-based GFR equations. 
To evaluate the performance of the CKD-EPI creatinine-cystatin C equation in 
subjects with cirrhosis, we compared it to GFR measured by nonradiolabeled 
iothalamate plasma clearance (mGFR) in 72 subjects with cirrhosis. We compared 
the "bias," "precision," and "accuracy" of the new CKD-EPI creatinine-cystatin C 
equation to that of 24-hour urinary creatinine clearance (CrCl), Cockcroft-Gault 
(CG), and previously reported creatinine- and/or cystatin C-based GFR-estimating 
equations. Accuracy of CKD-EPI creatinine-cystatin C equation as quantified by 
root mean squared error of difference scores (differences between mGFR and 
estimated GFR [eGFR] or between mGFR and CrCl, or between mGFR and CG equation 
for each subject) (RMSE = 23.56) was significantly better than that of CrCl 
(37.69, P = 0.001), CG (RMSE = 36.12, P = 0.002), and GFR-estimating equations 
based on cystatin C only. Its accuracy as quantified by percentage of eGFRs that 
differed by greater than 30% with respect to mGFR was significantly better 
compared to CrCl (P = 0.024), CG (P = 0.0001), 4-variable MDRD (P = 0.027), and 
CKD-EPI creatinine 2009 (P = 0.012) equations. However, for 23.61% of the 
subjects, GFR estimated by CKD-EPI creatinine-cystatin C equation differed from 
the mGFR by more than 30%.
CONCLUSION: The diagnostic performance of CKD-EPI creatinine-cystatin C equation 
(2012) in patients with cirrhosis was superior to conventional equations in 
clinical practice for estimating GFR. However, its diagnostic performance was 
substantially worse than reported in subjects without cirrhosis.