1. aDivision of Hospital Medicine
2. bCecil G. Sheps Center for Health Services Research
3. cDepartment of Biostatistics, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
4. dDivision of General Pediatrics and Adolescent Medicine, Department of Pediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
5. eDepartment of Pediatrics, Texas Tech University Health Sciences Center School of Medicine, Amarillo, Texas