1. Department of Medicine; University of Pennsylvania; Philadelphia PA
2. Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA
3. Department of Medicine; University of Arizona; Phoenix AZ
4. Department of Medicine; Mayo Clinic; Rochester MN
5. Department of Medicine; Penn State Milton S. Hershey Medical Center; Hershey PA