Estimation of glomerular filtration rate in South Asian healthy adult kidney donors

AIM: We evaluated the performance of serum creatinine based equations to estimate glomerular filtration rate (GFR) in South Asian healthy renal donors. METHODS: GFR by 99mTc-diethylenetriamine pentaacetic acid (DTPA) renogram (mGFR) in 599 renal donors was measured. GFR was estimated using a six variable modification of diet in renal disease formula (MDRD1), a four variable MDRD formula (MDRD2), Cockcroft-Gault creatinine clearance (CG CrCl), Cockcroft-Gault glomerular filtration rate (CG GFR) and the Mayo Clinic formula (Mayo GFR). The performance of various prediction equations was compared for global bias, precision (R(2)) and accuracy (percentage of estimated GFR (eGFR) falling within 15% and 30% of mGFR). RESULTS: The mean age was 37.4 +/- 11 years and 48.2% were male. The mGFR was 95.5 +/- 11.6 mL/min per 1.73 m(2). The bias (mL/min per 1.73 m(2)) was 7.5 +/- 0.9, -9.0 +/- 0.75, 13.1 +/- 0.9, 7.5 +/- 0.9 and 23.4 +/- 0.76 for CG CrCl, CG GFR, MDRD1, MDRD2 and Mayo GFR, respectively. R(2) was 0.082 for CG CrCl and MDRD1, 0.081 for CG GFR and MDRD2 and 0.045 for Mayo GFR. The percentages of eGFR falling within 15% and 30% of mGFR were 50.5 and 80.1 for CG CrCl, 65.8 and 84 for CG GFR, 50 and 74 for MDRD1, 54.3 and 80.1 for MDRD2 and 32 and 63.4 for Mayo GFR. Overall CG GFR performed better in estimating GFR in all subjects. CONCLUSION: The CG GFR equation was better than other equations to estimate GFR in South Asian healthy renal donors. We propose a new equation derived from the regression model in our study population to estimate GFR in a South Asian healthy adult population.