Comparison of Performance of Improved Serum Estimators of Glomerular Filtration Rate (GFR) to (99m)Tc-DTPA GFR Methods in Patients with Hepatic Cirrhosis.

Glomerular filtration rate (GFR) measurements are critical in patients with hepatic cirrhosis but potentially erroneous when based on serum creatinine. New equations for estimated GFR (eGFR) have shown variable performance in cirrhotics, possibly because of inaccuracies in reference methods for measured GFR (mGFR). The primary objective was to compare the performance of 4 improved eGFR equations with a 1-compartment, 2-sample plasma slope intercept 99mTc-DTPA mGFR method to determine whether any of the eGFR calculations could replace plasma 99mTc-DTPA mGFR in patients with cirrhosis. The secondary objective was to test the hypothesis that mGFR using voluntary voided urine collections introduces error compared with plasma-only methods. Methods: Fifty-four patients with hepatic cirrhosis underwent mGFR determinations from 2 plasma samples at 1 and 3 h after intravenous administration of 185 MBq of 99mTc-DTPA. GFR was also generated by a UV/P calculation derived from blood and urine samples. These mGFRs were compared with the eGFRs generated by 4 estimating equations: MDRD (Modified Diet in Renal Disease), CKD-EPI (Chronic Kidney Disease-Epidemiology Collaboration) (serum creatinine [SCr]), CKD-EPI (cystatin [CysC]), and CKD-EPI (CysC+SCr). eGFRs were compared with mGFRs by Pearson correlation, precision, bias, percentage bias, and accuracy (eGFRs varying by <10% [p10], <20% [p20] or <30% [p30] from the corresponding mGFR). Results: All eGFRs showed poorer performance when the UV/P 99mTc-DTPA mGFR was used as the reference than when the plasma 99mTc-DTPA mGFR was used. When compared with the plasma 99mTc-DTPA mGFR method, the performance of all eGFR equations was superior to most published reports. There was a moderately good positive correlation between eGFRs and mGFRs. When compared with plasma 99mTc-DTPA mGFR, precision of eGFRs was in the range of 14-20 mL/min and showed a negligible bias. Compared with the plasma 99mTc-DTPA mGFR, CKD-EPI (CysC+SCr) showed the best overall performance and accuracy, at 85.19% (p30), 75.93% (p20), and 42.59% (p10). Conclusion: Estimating equations for measuring eGFR performed better than in most published reports, attributable to use of the plasma 99mTc-DTPA mGFR method as a reference. CKD-EPI (CysC+SCr) eGFR showed the best overall performance. However, more discriminating methods may be required when accurate GFR measurements are necessary. mGFR measurements using urine collections may introduce error compared with plasma-only methods.

Haddadin Z ，Lee V ，Conlin C ，Zhang L ，Carlston K ，Morrell G ，Kim D ，Hoffman JM ，Morton K ... -  《-》

Serum cystatin C unmasks renal dysfunction in cirrhosis and performs better in estimation of glomerular filtration rate.

Velayudham B ，Thomas RG ，Vasudevan C ，Senthilkumar RP ，Thirumalvalavan ，Murugesan ... -  《-》

Cystatin C-Based Equation for Predicting the Glomerular Filtration Rate in Kidney Transplant Recipients.

Precise monitoring of the glomerular filtration rate (GFR) is needed to estimate the allograft function in kidney transplant recipients (KTRs). The GFR is widely estimated with the use of formulas based on serum cystatin C (SCys) and serum creatinine (SCr) levels. We compared the efficacy of SCys-based equations with that of SCr-based equations to predict the allograft function. We calculated the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI Cr), CKD-EPI creatinine-cystatin C (CKD-EPI Cr/Cys), and CKD-EPI cystatin C (CKD-EP ICys) equations in 70 KTRs. The measured GFR (mGFR) was defined as the GFR estimated by technetium-99m-diethylene triamine pentaacetic acid (99mTc-DTPA) clearance. The accuracy and precision of the equations were compared with the mGFR. The performance characteristics of SCr and SCys were analyzed with the use of receiver operating characteristic (ROC) curves to ascertain the sensitivity and specificity at the cutoff value of <45 mL/min/1.73 m2 DTPA. Overall, MDRD and CKD-EPICys did not show significant differences from mGFR (P = .05 and P = .077, respectively), whereas CKD-EPI Cr and CKD-EPI Cr/Cys significantly underestimated mGFR (P < .001 and P = .005, respectively). In the subgroup of patients with mGFR <45 mL/min/1.73 m2, CKD-EPI Cys showed little bias (P = .122), whereas MDRD significantly underestimated mGFR (P = .037). The area under the ROC curve for predicting mGFR <45 mL/min/1.73 m2 was 0.80 for SCys, which was better than that for SCr at 0.763. Cystatin C-based equations showed better predictive performance of the allograft function than creatinine-based equations for the KTRs, including patients with lower GFR. Cystatin C level might be a good alternate measurement to monitor the allograft function.

Yang Y ，Kim KY ，Hwang I ，Yim T ，Do W ，Kim MJ ，Lee S ，Jung HY ，Choi JY ，Park SH ，Kim YL ，Kim CD ，Cho JH ... -  《-》

Performance of the creatinine-based and the cystatin C-based glomerular filtration rate (GFR) estimating equations in a heterogenous sample of patients referred for nuclear GFR testing.

Cystatin C may be a more accurate marker of the glomerular filtration rate (GFR) than creatinine. We evaluated the performance of the creatinine-based abbreviated modification of diet in renal disease (MDRD), the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, and 6 cystatin C-based equations in estimating GFR (eGFR) in a heterogeneous sample of patients. Measured GFR (mGFR) was obtained from the plasma clearance of 99mtechnetium Diethylenetriaminepentaacetic acid in 42 adult patients referred for nuclear GFR testing (January to March 2008). We evaluated the bias, precision, and accuracy of the abbreviated MDRD, CKD-EPI, Filler, Grubb, Hoek, Larsson, Le Bricon, and Rule eGFR equations. Participants had a mean mGFR of 70.9 mL/min/1.73 m2 (range: 22-125 mL/min/1.73 m2), a median age of 57 years (interquartile range: 45, 66), were 62% male, and were 38% liver transplant recipients. Correlation coefficients between eGFRs and mGFR ranged from 0.65 to 0.87 (each P<0.001). The cystatin C-based Hoek equation had the best overall performance with a low bias (-1.4 mL/min/1.73 m2), good precision (13.3 mL/min/1.73 m2), and greatest accuracy, with 93% of values within 30% of mGFR. Although the CKD-EPI equation had the lowest bias (-0.6 mL/min/1.73 m2), it had poor precision (20.7 mL/min/1.73 m2) and low accuracy, with only 69% of values within 30% of mGFR. The Hoek equation remained accurate and had the least bias when patients were grouped according to the history of liver transplantation and the mGFR above or below 60 mL/min/1.73 m2. In this heterogeneous sample, the cystatin C-based Hoek equation performed the best overall, regardless of mGFR level or history of liver transplantation.

Huang SH ，Macnab JJ ，Sontrop JM ，Filler G ，Gallo K ，Lindsay RM ，Clark WF ... -  《-》

Performance of glomerular filtration rate estimation equations in Congolese healthy adults: The inopportunity of the ethnic correction.

Bukabau JB ，Sumaili EK ，Cavalier E ，Pottel H ，Kifakiou B ，Nkodila A ，Makulo JRR ，Mokoli VM ，Zinga CV ，Longo AL ，Engole YM ，Nlandu YM ，Lepira FB ，Nseka NM ，Krzesinski JM ，Delanaye P ... -  《PLoS One》