An Evaluation of the new 2021 Creatinine-Based Equation for Estimating Glomerular Filtration Rate (eGFR) in Pakistanis

Background: The new eGFR equation without race coefficients was recently developed and published by the CKD-EPI Collaboration. The new equation termed CKD-EPI 2021 has been endorsed by the National Kidney Foundation and the American Society of Nephrology. It is important to understand the impact this new equation might have on clinical decision making in practice; hence, this study is planned to evaluate the CKD-EPI 2021 equation in Pakistani population. To evaluate the performance of CKD-EPI 2021, CKD-EPI 2009, CKD-EPI Pak, and MDRD equations taking CrCl as gold standard. Methods: This retrospective cross-sectional study was conducted at the section of Chemical Pathology, Department of Pathology and Laboratory Medicine, in collaboration with section of Nephrology, Department of Medicine, Aga Khan University, Karachi. Consecutive laboratory results of subjects above 18 years; tested for CrCl or three months December 2021 to February 2022 was retrieved from the integrated laboratory management system (iLMS). Demographic details including gender and age alongside biochemical results of CrCl and serum Cr were recorded on a pre-structured questionnaire. Statistical analysis of the data will be performed using Statistical Package of Social Sciences (SPSS) version 22. Results: After excluding those below 18 years of age, 2,609 cases were included in the final data analysis, with 1,419 (54.4%) males and 1,190 (45.6%) females. Mean age of the group was 52.8 ± 14.9 years. Among the 4 formulae tested against CrCl, CKD-EPI Pak showed the strongest correlation (r² = 0.83), highest sensitivity 93.2% and negative predictive value of 93.0% with an overall agreement of 88%. Conclusions: The CKD-EPI Pak equation is more accurate and precise in estimating GFR in Pakistani population. Based on the successful five years of experience of reporting eGFR using this equation by a large tertiary care hospital in Pakistan, this is high time to propagate its incorporation reflexly with SCr laboratory reports with no additional cost constraints.