J Coll Physicians Surg Pak 2020 Jul;30(7):701-706
Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan.
Objectives: To assess and compare the glomerular filtration rate (eGFR) estimated through MDRD and CKD-EPIcr equations in early and late stages of chronic kidney disease on biochemical marker creatinine (eGFRcr), cystatin C (eGFRcys); and combined (eGFRcr-cys), using CKD-EPI equation.
Study Design: Observational, comparative cross-sectional study.
Place And Duration Of Study: Chemical Pathology and Endocrinology Department, Armed Forces Institute of Pathology (AFIP), Rawalpindi in collaboration with Armed Forces Institute of Urology (AFIU), Rawalpindi from October 2019 to March 2020.
Methodology: GFR was assessed on the basis of creatinine clearance taking serum and 24-hour urinary specimens. MDRD and CKD-EPI equations were applied to calculate eGFR by serum creatinine (eGFRcr), cystatin C (eGFRcys), and combined (eGFRcr-cys). Pearson correlation technique was used to compare eGFR calculated by different equations with creatinine clearance in different stages of CKD. Performance of equations was evaluated and compared in different stage of CKD.
Results: A total of 181 subjects were enrolled. Median age was 57 years (IQR, 25). Median (IQR) GFR (ml/min/1.73m2) calculated by CrCl, MDRD, CKD-EPIcr, CKD-EPIcys and CKD-EPIcr-cys equations were 45.1 (41.5), 50.6 (23.8), 52.0 (28.0), 43.0 (65.0) and 45 (47), respectively. eGFR calculated by CKD-EPIcr had positive and slightly higher correlation (r=0.880) than MDRD study equation (r=0.867). While comparing the markers, it was observed that CKD-EPIcys had better correlation in early stages of CKD (r=0.889); whereas, CKD-EPIcr performed better in late stages (r=0.896). CKD-EPIcr-cys had the highest correlation (r=0.984) at all stages of CKD.
Conclusion: eGFR calculated by CKD-EPI equation considered as better diagnostic efficient response than MDRD equation in diagnosis and staging of chronic kidney disease. While applying CKD-EPI equation for measurement of eGFR, eGFRcr-cys performs better than any of eGFRcr or eGFRcys at all stages of CKD. Key Words: Estimated glomerular filtration rate (eGFR), Cystatin C (Cys), Creatinine (Cr), Creatinine clearance (CrCl), CKD-EPI equation, MDRD equation.