1 Department of Emergency Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC. Electronic address: tim_platts-mills@med.unc.edu.
2 Cecil G. Sheps Center for Health Services Research and Schools of Social Work and Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC.
3 Cecil G. Sheps Center for Health Services Research and Department of Family Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC.