Evaluation of 'CKD-EPI Pakistan' Equation for estimated Glomerular Filtration Rate (eGFR): A Comparison of eGFR Prediction Equations in Pakistani Population

Objective: To evaluate the results of 24-hour urinary creatinine clearance (CrCl) with estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), CKD-EPI Pakistan (CKD-EPI Pak), Cockcroft Gault (CG) and 4-variable Modification of Diet in Renal Disease (MDRD) equations. Study Design: Descriptive, cross-sectional study. Place and Duration of Study: Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University, Karachi, from June to October 2013. Methodology: Laboratory data of subjects >= 18 years ordering 24-hour urinary CrCl from June to October 2013 was retrieved. Statistical comparison of eGFR using CKD-EPI, CKD-EPI Pak, CG and MDRD with the timed urine collection CrCl was done using regression analysis. Results: The mean age of the group (n=670) was 51.3 +/- 15.4 years with a median of 53 (IQR:22.3) years, 55.7% being males. Median BMI of males and females was 26.98 kg/m(2) (IQR:7.09) and 26.16 kg/m(2) (IQR:6.97), respectively. Mean GFR using 24-hour creatinine clearance was 57.1 +/- 35.9 ml/min/1.73m(2) with a median of 51 ml/min/1.73m(2). Urinary creatinine clearance showed strong correlation with CG, MDRD, CKD-EPI and CKD-EPI Pak, showing r=0.78, r=0.79, r=0.82, and r=0.82, respectively. Sensitivity was highest for the CKD-EPI Pakistan (84.7%). Similarly, CKD-EPI Pakistan equation showed the highest agreement (88.7%) with CrCl compared to the other formulae. Conclusion: The CKD-EPI Pak equation is more accurate and precise than the CG, CKD-EPI and MDRD in estimating GFR in Pakistani population.