title: Accuracy of GFR estimation formula in determination of glomerular filtration rate in kidney donors: Comparison with 24 h urine creatinine clearance.
abstract: To determine the accuracy of estimated glomerular filtration rate (eGFR) using the modification of diet in renal disease (MDRD), Cockcroft-Gault (CG), and chronic kidney disease epidemiology (CKD-EPI) formulas in potential kidney donors compared with 24-h urine creatinine clearance, we studied 207 potential live kidney donors in our center. There were 126 (60.9%) males and 81 (39.1%) females. Male:female ratio was 1.6:1. The age of the donors ranged from 18-58 years, with mean age of 35.30 ± 9.23 years and most of the individuals were below 40 years of age. The body mass index (BMI) was calculated and venous blood samples were obtained for the measurement of serum creatinine and every study participant was instructed to collect 24-h urine. GFR was calculated based on 24-h urine creatinine clearance and the formulas. The accuracy of GFR estimation formula was taken as positive if the GFR calculated by the formulas and urine creatinine clearance fell between 90-120 mL/min/1.73 m(2). The accuracy of the MDRD formula was 48.8% and the CG formula was 41.5% whereas the accuracy of the CKD-EPI formula was 78.2%. The accuracy of the eGFR using the MDRD formula was significantly higher in males than females (57.9% vs. 33.3% P = 0.001), while there was no statistically significant difference in the eGFR between them in case of the use of the CG and the CKD-EPI formulas. BMI and obesity had no effect on the accuracy of eGFR by the use of the different formulas. The performance of GFR estimation formulas was sub optimal and these either underestimated and/or over-estimated the GFR in healthy subjects. CKD-EPI is closer to 24 -h urinary creatinine clearance in the calculation of eGFR. However, none of the eGFR formulas can be used in renal transplant donors because of their low accuracy, and 24-h urine creatinine clearance should be used for evaluation of the GFR in this population.
authors.forename: Abdul Rauf
authors.initials: AR
authors.lastname: Hafeez
authors.affiliation: Department of Nephrology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan.
authors.forename: Muhammad Khalid
authors.initials: MK
authors.lastname: Idrees
authors.forename: Syed Fazal
authors.initials: SF
authors.lastname: Akhtar
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D064368:Healthy Volunteers; D006801:Humans; D007668:Kidney / Q000502:physiology*; D016030:Kidney Transplantation / Q000379:methods*; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010154:Pakistan; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D016482:Urinalysis; D055815:Young Adult
chemical_list: D015415:Biomarkers; D003404:Creatinine