Quantile regression adjusted for comorbidities and age (fourth order polynomial) for CKD-EPI equation. The X axis displays eGFRs by quantiles (0-0.2 being the lowest 20% and 0.8- 1.0 being the highest 20%). The Y axis shows the difference in eGFR in ml/min in blacks compared to whites. For example, a black individual with an eGFR at the 40th percentile would have an eGFR approximately 3 ml/min higher than a white individual by CKD-EPI method. Using the MDRD equation, a black at the 40th percentile, would have an eGFR approximately 6 ml/min higher than a white individual.