Figure 1.

Changes caused by switching from the 2009 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation with a race coefficient to the 2021 CKD-EPI creatinine equation refit without the race variable as a function of age (x-axis, 18-92 years) and the 2009 CKD-EPI estimated glomerular filtration rate (eGFR) values (y-axis, 1-105 mL/min/1.73 m²). (A) Contour plots of absolute differences in eGFR (2021 CKD-EPI refit minus 2009 CKD-EPI). Contours were drawn for every 1 mL/min/1.73 m² difference. Areas where the 2021 CKD-EPI refit eGFR was lower than that in the 2009 CKD-EPI were shaded in red and where it was higher were shaded in green. (B) Contour plots of the relative differences in eGFR (100 × [2021 CKD-EPI refit − 2009 CKD-EPI] / 2009 CKD-EPI). Contours were drawn for every 1% difference. Areas where the 2021 CKD-EPI refit eGFR was lower than that in the 2009 CKD-EPI were shaded in red and where it is higher were shaded in green. (C) Region plots showing discordant chronic kidney disease stages. Areas where the chronic kidney disease stage according to 2021 CKD-EPI refit was higher than that according to 2009 CKD-EPI (ie, eGFR was worse) were shaded in red, and areas where the chronic kidney disease stage was lower (ie, eGFR was better) were shaded in green. In the white areas, chronic kidney disease stages are the same with both equations.