| Affiliation: | 1. School of Medicine, University of North Carolina, , Chapel Hill, North Carolina;2. Department of Family Medicine, University of North Carolina, , Chapel Hill, North Carolina;3. Department of Biostatistics, University of North Carolina, , Chapel Hill, North Carolina;4. Department of Anesthesiology, University of North Carolina, , Chapel Hill, North Carolina;5. Department of Social Medicine, University of North Carolina, , Chapel Hill, North Carolina;6. Department of Medicine, University of North Carolina, , Chapel Hill, North Carolina;7. Department of Emergency Medicine, University of North Carolina, , Chapel Hill, North Carolina |
