10. Estimated glomerular filtration rate (GFR) ≤ 30 mL/min/1.73m² as calculated by Modification of Diet in Renal Disease (MDRD) study equation [MDRD = 186 X serum creatinine (mg/dl) 1.154 X years -0.203 X (0.742 if female) X (1.210 if African American)].