Performance of the European Kidney Function Consortium (EKFC) creatinine-based eGFR equation and other eGFR equations in a north European population. A multicentre study in Norway

OBJECTIVES: Accurate estimation of glomerular filtration rate (eGFR) is necessary for early detection and staging of chronic kidney disease (CKD), risk stratification, and guiding therapies that prevent complications and progression to advanced CKD. This study aimed to evaluate the performance of different eGFR equations in a large national cohort. METHODS: This multicentre study was conducted at six university hospitals in Norway. Retrospective data from patient's medical records from 2005 to 2024 for 5,552 adults and 2,981 children were used to validate several creatinine-based eGFR equations against measured GFR (mGFR) by Iohexol clearance. Performance was assessed using median bias and P30 accuracy (proportion of eGFR within ±30 % of mGFR). RESULTS: The European Kidney Function Consortium (EKFC) creatinine-based eGFR equation outperformed the CKD-EPI 2009 and 2021, the MDRD in adults, the Schwarts bedside and the CKiD U25 equations in children ≥2 years and was comparable to the Lund-Malmö equation (LM) in adults. Both CKD-EPI equations had the lowest accuracy and were overestimating GFR in young people (<25 years) and elderly patients (≥65 years). Replacing the CKD-EPI equations with the EKFC equation will result in lower eGFR values and a higher prevalence of CKD stages 3-5. Replacing the LM and MDRD with the EKFC equation will result in higher eGFR and a lower prevalence of CKD stages 3-5. CONCLUSIONS: The EKFC equation was overall the best suited creatinine-based eGFR equation for this Norwegian population from 2 years of age. Clinicians should be informed about clinical implications of shifting from other equations to the EKFC equation.