1Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts

2The Research Institute at Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio

Correspondence: Dr. Sahir Kalim, email: [email protected]

See related article, “Longitudinal Plasma Metabolome Patterns and Relation to Kidney Function and Proteinuria in Pediatric CKD,” on pages 837–850.