Comparison of Cystatin C and Creatinine-based Glomerular Filtration Rate Formulas with 51Cr-EDTA Clearance in Patients with Cirrhosis

Abstract

SummaryBackground and objectives Renal function is an important predictor of survival in cirrhosis and liver transplantation. GFR estimates using serum cystatin C (CysC) are proposed as better predictors of renal function than ones on the basis of serum creatinine (Cr). Our aims were: (1) evaluate correlations between serum CysC and different methods of creatinine measurements; (2) compare CysC and Cr GFR formulas with 51 Cr-EDTA; and (3) evaluate liver-related parameters potentially influencing GFR.Design, setting, participants, & measurements 254 blood samples in 65 patients with cirrhosis correlating CysC with four Cr methods were used; another 74 patients comparing 51 Cr-EDTA GFR to Modification of Diet in Renal Disease and Larsson and Hoek formulas for CysC were also included. Agreement was assessed using Bland-Altman plots and concordance correlation coefficients. Multivariate linear regression analysis was used for GFR predictors.Results Serum CysC correlated modestly with O'Leary modified Jaffe, compensated kinetic Jaffe, enzymatic creatinine, and standard kinetic Jaffe 0.72/0.71/0.72/0.72 (all P Ͻ 0.001). Bland-Altman agreement with 51 Cr-EDTA GFR was poor; the best agreement was Modification of Diet in Renal Disease (concordance 0.61; 95% CI, 0.47 to 0.71); the worst agreement was the Hoek formula (concordance 0.46; 95% CI, 0.27 to 0.61). A new GFR formula including the Child-Pugh score improved the accuracy of Cr GFR formulas compared with 51 Cr-EDTA GFR.Conclusions Estimated GFR in cirrhosis is not better with CysC formulas compared with creatinine ones: specific formulas may be necessary.

Difficulties in diagnosing acute kidney injury post liver transplantation using serum creatinine based diagnostic criteria

“…GFR estimations were significantly different to inulin clearance. In the second study serum cystatin C formulas not only significantly overestimated renal clearance compared with 51 Cr-EDTA but did not provide any advantage over serum creatinine formulas [35] , and serum cystatin C values were significantly affected by the presence of ascites. Although a third study reported cystatin C to more accurately represent renal function than serum creatinine [50] .…”

“…It has been recommended that creatinine results used for calculating eGFR should be traceable to an IDMS reference method [34] , but the IDMS standards do not correct for the effects of chromogens. To overcome the problem that these formulae were derived from cohorts without liver disease new formulae for patients with cirrhosis have been proposed including adding the Child Turcot Pugh (CTP) score and ascites into the formula [35] . These newer formulae have been reported to show better agreement with "true" GFR, compared to the MDRD formulae, but require further external validation before they can be introduced into clinical practice.…”

“…The original cystatin C equations were all derived from non-liver disease populations [47,48] . Recentstudies have evaluated cystatin C GFR formulas in patients with cirrhosis [35] . One reported that although cystatin C formulas were more accurate than the creatinine formulas [49] .…”

AKI in a Patient with Cirrhosis and Ascites

“…Cystatin C production is also affected by chronic liver disease, and it increases as patients progress from ChildTurcotte-Pugh stage A to C. Thus, as with serum creatinine, cystatin C also tends to overestimate kidney function, and it has not been proven to offer any advantages in assessing GFR over use of serum creatinine levels (18). Isotopic and radiocontrast methods can be used to assess kidney function in patients with cirrhosis, but they are susceptible to errors caused by redistribution within ascitic and extracellular fluid (19).…”

Performance of Methods to Assess Kidney Function in a Predominantly Overweight Sample of Patients with Liver Disease

“…17 The sum of information available to date on cystatin C-based assessment equations in patients with liver disease provides reasonable evidence in support of its use as a marker of GFR, but additional studies are needed to support regular use in clinical practice. [18][19][20][21][22][23] The characteristics of vancomycin (V) also make it a reasonable candidate to consider as a marker of kidney function. V is a tricyclic glycopeptide antibiotic commonly used in hospitalized patients with liver disease and often requires measurement of serum concentrations to evaluate therapy.…”