1. Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center , Nashville, TN 37203 , USA
2. School of Medicine, Vanderbilt University , Nashville, TN 37203 , USA
3. Department of Computer Science, Vanderbilt University , Nashville, TN 37203 , USA
4. Department of Biomedical Informatics, Vanderbilt University Medical Center , Nashville, TN 37203 , USA
5. Department of Surgery, Vanderbilt University Medical Center , Nashville, TN 37203 , USA
6. Metamor Institute, Pennington Biomedical Research Center , Baton Rouge, LA 70808 , USA