Prospects for improved glomerular filtration rate estimation based on creatinine-results from a transnational multicentre study

Background. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation is routinely used to assess renal function but exhibits varying accuracy depending on patient characteristics and clinical presentation. The overall aim of the present study was to assess if and to what extent glomerular filtration rate (GFR) estimation based on creatinine can be improved. Methods. In a cross-sectional analysis covering the years 2003-17, CKD-EPI was validated against measured GFR (mGFR; using various tracer methods) in patients with high likelihood of chronic kidney disease (CKD; five CKD cohorts, n ¼ 8365) and in patients with low likelihood of CKD (six community cohorts, n ¼ 6759). Comparisons were made with the Lund-Malmö revised equation (LMR) and the Full Age Spectrum equation. Results. 7In patients aged 18-39 years old, CKD-EPI overestimated GFR with 5.0-16 mL/min/1.73 m² in median in both cohort types at mGFR levels <120 mL/min/1.73 m². LMR had greater accuracy than CKD-EPI in the CKD cohorts (P₃₀, the percentage of estimated GFR within 30% of mGFR, 83.5% versus 76.6%). CKD-EPI was generally the most accurate equation in the community cohorts, but all three equations reached P₃₀ above the Kidney Disease Outcomes Quality Initiative benchmark of 90%. Conclusions. None of the evaluated equations made optimal use of available data. Prospects for improved GFR estimation procedures based on creatinine exist, particularly in young adults and in settings where patients with suspected or manifest CKD are investigated.