Figure. Difference Between Estimated and Measured Glomerular Filtration Rate (GFR) With and Without the African American (AA) Coefficient Across a Range of Estimated GFR Values.

Data from 2601 AA participants from the Chronic Kidney Disease Epidemiology Collaboration development and internal validation sample were analyzed. Measured GFR (mGFR) values were obtained using urinary clearance of iothalamate. Estimated GFR based on serum creatinine (eGFRcr) values were computed using serum creatinine traceable to an international reference standard. We computed eGFRcr values with (gray) and without (orange) the application of the AA coefficient and removed values less than the 2.5 percentile and greater than the 97.5 percentile of these distributions, leaving 2463 participants for the analysis. Model plotted represents the generalized additive models for eGFRcr (mL/min/1.73 m²) on the difference between mGFR and eGFRcr (mL/min/1.73 m²) (excluding an additional 190 participants from the plot). The colored area along the lines represents 95% CIs of the estimate. The dashed line and darker orange shading indicate extrapolation of the model beyond the available data.