1. Divisions of Nephrology, University of Texas Health Science Center San Antonio, San Antonio, Texas
2. School of Health Professions, University of Texas Health Science Center San Antonio, San Antonio, Texas
3. Audie L. Murphy Veterans Memorial Hospital, STVHCS, San Antonio, Texas
4. Division of Nephrology, Western Galilee Hospital, Nahariya, Israel
5. Clinical Epidemiology, School of Medicine, University of Texas Health Science Center San Antonio, San Antonio, Texas
6. Division of Endocrinology, University of Pisa, Italy