title: Comparison of equations to estimate the glomerular filtration rate in post-renal transplant chronic kidney disease patients.
abstract: We determined the performance of estimated glomerular filtration rate equations (eGFR) including MDRD2-Isotope Dilution Mass Spectrometry (MDRD2-IDMS), Cockcroft-Gault (CG) and Virga to measure post-transplant chronic kidney disease (CKD) stages 1-4, using simultaneous isotope GFR (iGFR) measurement. The study was conducted in 97 patients. The eGFR results measured by CG and Virga were normalized to 1.73 m². Analysis of relative and absolute bias, error, scatter, correlation coefficient of variance and accuracy within the 30% range from the reference iGFR result was performed using standard techniques. There were 135, 242, 314 and 82 scans, respectively, in CKD stages 1-4. Bias and accuracy of GFR estimators varied significantly across the CKD stages. In stages 1 and 2, CG had the best error of -12.7 and 0.2 mL/min/1.73 m², respectively, while Virga had the highest accuracy of 74.3% and 85.5, respectively. In stages 3 and 4, MDRD2-IDMS had the best error of -0.52 and 5.8, respectively. Accuracy was the best at 75.1% for Virga in stage 3, while it was the highest of 70.7% for MDRD2-IDMS in stage 4. Virga had the highest accuracy of 75.2% in stage 4. The worst bias was for MDRD2-IDMS in stage 2 (-36.8 mL/min/1.73 m²) and the best bias was for CG in stage 2 (-0.33 mL/min/1.73 m²). The eGFR estimators have inconsistent performances in the various stages of CKD and, thus, another limitation is added to their validity to substitute for the gold standard methods.
authors.affiliation: National Liver Institute, Menoufiya University, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Attia
authors.forename: Ahmed
authors.initials: A
authors.lastname: Zahran
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shoker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002138:Calibration; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology / Q000601:surgery*; D007674:Kidney Diseases / Q000503:physiopathology / Q000601:surgery*; D007677:Kidney Function Tests / Q000592:standards; D016030:Kidney Transplantation; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011865:Radioisotope Dilution Technique; D019275:Radiopharmaceuticals; D012015:Reference Standards; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016284:Technetium Tc 99m Pentetate; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019275:Radiopharmaceuticals; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate