Under the current paradigm for chronic kidney disease (CKD), estimates of glomerular filtration rate (eGFR) and proteinuria are integral to defining the condition, determining its severity, gauging patients’ risk for adverse clinical outcomes, and estimating the population burden of disease.1 Patients’ risks for end-stage kidney disease (ESKD), mortality, cardiovascular events, and metabolic complications, which vary systematically by disease stage, are then important in guiding treatment recommendations and organizing care.