1. Department of Medicine, Duke University School of Medicine , Durham, NC, USA
2. Department of Medicine, Medical University of South Carolina , Charleston, SC, USA
3. Department of Medicine, Vanderbilt University School of Medicine , Nashville, TN, USA
4. Biomedical Informatics Center, Medical University of South Carolina , Charleston, SC, USA
5. Department of Internal Medicine, East Tennessee State University College of Medicine , Johnson City, TN, USA
6. Department of Medicine, University of North Carolina School of Medicine , Chapel Hill, NC, USA