Impact of switching from the CKD-EPI2009 to the EKFC equation on the epidemiology of chronic kidney disease and Nephrology workload

Background Chronic kidney disease (CKD) can be diagnosed by estimating the glomerular filtration rate (eGFR) using serum creatinine-based equations, mainly CKD-EPI2009. The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently supported adopting the European Kidney Function Consortium (EKFC) equation. Methods We compared eGFR values obtained using CKD-EPI2009 and EKFC in analytical records from a single lab corresponding to 216 637 individual adults receiving Primary and Specialized healthcare in 2023 in a catchment area in Madrid (Spain). Results Switching from CKD-EPI2009 to EKFC resulted in a 39.6% higher prevalence of low eGFR consistent with CKD G3-G5 (13.4% vs 9.6% in the full population and 36.3% vs 25.6% among people aged ≥ 65 years). Among 33 789 patients with albuminuria assessments, the prevalence of eGFR and albuminuria values consistent with CKD G1-G5 was 36.3% for EKFC and 32.5% for CKD-EPI2009. Among newly identified patients with potential CKD G3-G5, 25% had A2-A3 albuminuria. Differences in CKD prevalence between both equations were observed for men and women. According to National guidelines, in the first year after the switch, 0.33 to 0.58 full-time nephrologist equivalents would be needed to care for newly diagnosed patients with CKD in this catchment area, potentially resulting in 5 to 9 nephrologists needed for the Madrid region. Conclusion In this retrospective analysis, a switch from the creatinine-based CKD-EPI2009 to the EKFC eGFR equation would increase the prevalence of CKD, especially among the elderly. EKFC may identify patients with A2-A3 albuminuria as having CKD that may have been missed by CKD-EPI2009in healthcare systems with low uptake of albuminuria assessments.