Estimation of glomerular filtration rates after orthotopic liver transplantation: Evaluation of cystatin C-based equations.
Early detection of renal dysfunction in patients after orthotopic liver transplantation is important. Creatinine-based equations to estimate glomerular filtration rate (GFR) were found to be less accurate in liver transplant recipients than in their original populations. Since cystatin C (CysC) is independent from muscle mass and hepatic biosynthesis, we evaluated the diagnostic accuracy of 3 CysC-based equations (Larson, Hoek, and Filler formulae) that are based on the same CysC method as that of our center in comparison to the abbreviated creatinine-based modification of diet in renal disease (MDRD) formula in 59 liver transplant recipients. "True GFR" was measured by 99mTc-diethylene triamine pentaacetic acid ((99m)Tc-DTPA) clearance. Neither correlation with the GFR (correlation coefficients: 0.594-0.640) nor precision (root mean square error: 15.7-18.17 mL/min/1.73 m(2)) differed significantly between the tested formulae. The biases of the Hoek and Larsson formulae were significantly smaller than those of the MDRD and Filler equations (-0.1 and -2.3 vs. 10.1 and 7.9 mL/min/1.73 m(2), respectively; P </= 0.0023). Mean estimates of MDRD (61.9 +/- 21.4 mL/min/1.73 m(2)) and Filler (61.2 +/- 22.1 mL/min/1.73 m(2)) differed significantly from the measured GFR (52.3 +/- 17.5 mL/min/1.73 m(2); P < 0.005), whereas Larsson and Hoek did not (49.5 +/- 20.2 and 51.4 +/- 17.9 mL/min/1.73 m(2), respectively). Accuracy within 30% and 50% of the true GFR was best for the Hoek (76.3% and 93.2%) formula, albeit not significantly different from MDRD (64.4% and 83.1%). Taken together, these data show the best overall performance for GFR estimates derived from the Hoek equation with respect to bias, precision, and accuracy.
Gerhardt
Thomas
T
Department of Internal Medicine I, University of Bonn, Bonn, Germany. thomas.gerhardt@ukb.uni-bonn.de
Pöge
Uwe
U
Stoffel-Wagner
Birgit
B
Ahrendt
Manuela
M
Wolff
Martin
M
Spengler
Ulrich
U
Palmedo
Holger
H
Sauerbruch
Tilman
T
Woitas
Rainer P
RP
D000328:Adult; D003404:Creatinine / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis* / Q000178:diet therapy / Q000209:etiology*; D016031:Liver Transplantation / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011184:Postoperative Period; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D019275:Radiopharmaceuticals; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate