1. Division of General Medicine and Clinical Epidemiology, Department of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill
2. Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill, Chapel Hill
3. Division of General Pediatrics and Adolescent Medicine, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill
4. Department of Pediatrics, Wake Forest School of Medicine, Winston-Salem, North Carolina
5. Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina