"Comparison of creatinine based glomerular filtration rate estimation equations in voluntary Indian kidney donors: A single centre study"

Aim: In transplantation, accurate donor glomerular filtration rate (GFR) estimation is crucial. While various creatinine based equations are in use, none are validated in Indians, thus this study was conducted to judge accuracy of creatinine based GFR estimation equations and urinary creatinine clearance. Methods: A single-centre, observational and retrospective study at a tertiary care hospital. Adult voluntary donors GFR measured (mGFR) by Tc‑99m DTPA were included. Primary outcome was performance of estimated GFR (eGFR) by Cockcroft-Gault's formula corrected for body surface area (CG-BSA), Modification of diet in renal disease (MDRD) 4/6 and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI); Secondary outcome was performance of 24 hour urinary creatinine clearance (Cr Cl). Results: 102 kidney donors were analysed with mean age of 45.89 ± 9.98 years and 85.3% females. Mean ± SD mGFR by Tc‑99m DTPA was 82.11 ± 14.32 ml/min/1.73m2. Mean ± SD eGFR (ml/min/1.73m2) by CG-BSA was 99.68 ± 23.71, by MDRD-4 was 98.25 ± 28.61, by MDRD-6 was 93.66 ± 19.44 and by CKD-EPI was 111.14 ± 31.61. Lowest bias (2.3), highest precision (16.23) and accuracy (97.1%) was with MDRD-6; 24-hour urinary Cr Cl highly overestimated GFR (158.27 ml/min/1.73 m2) with highest bias, lowest precision and accuracy. Conclusion: Among the equations, MDRD-6 was the most precise and accurate with 24 hour urinary creatinine clearance being the least reliable. This study highlights the need for a correction factor or a new GFR estimation equation and not to consider urinary Cr Cl to assess donor GFR.