1 North Carolina Rural Health Research Program, Cecil G. Sheps Center for Health Services Research, The University of North Carolina at Chapel Hill, Chapel Hill. Electronic address: tmalone@live.unc.edu.
2 North Carolina Rural Health Research Program, Cecil G. Sheps Center for Health Services Research, The University of North Carolina at Chapel Hill, Chapel Hill.
3 Department of Emergency Medicine, University of New Mexico, Albuquerque; Department of Psychiatry and Behavioral Sciences, University of New Mexico, Albuquerque.