Automated Reporting of Estimated Glomerular Filtration Rate: A Comparison of Creatinine Clearance, Modification of Diet in Renal Disease and Cockcroft Gault Equations from Pakistan

Abstract

Objectives: To facilitate early detection of chronic kidney disease, many organizations now recommend reflex reporting of estimated glomerular filtration rate (eGFR) whenever serum creatinine (Cr) is measured. To compare two widespread eGFR equations with creatinine clearance (CrCl) calculated through a timed urine collection. Methodology: Laboratory data of subjects’ ≥ 18 years tested for CrCl from October 2010 to December 2010 was retrieved from laboratory information system of Aga Khan University Hospital. Statistical comparison of eGFR using Cockcroft Gault (CG) and 4-variable Modification of Diet in Renal Disease (MDRD) formulae with CrCl was performed. Results: Six hundred and seventy subjects with CrCl were studied. Mean age of the group was 51 ±15 years, 55.7 % being males. Mean glomerular filtration rate using CrCl, MDRD and CG were 57.1 (±35.9), 57.8 (±33.6) and 68.7 (±41.5) ml/min respectively. Deming regression analysis generated MDRD = 5.23 + 0.92 (CrCl) and CG = 0.23 + 1.2 (CrCl) for comparison of CrCl results with those of MDRD and CG respectively. Comparing MDRD and CrCl, Bland Altman revealed acceptable agreement with a minimal bias of 0.65 ml/min. Conclusion: We suggest that automatic reporting of eGFR using MDRD can be implemented in clinical laboratories when serum Cr is reported.