1. Division of Gastroenterology; Department of Medicine; University of Pennsylvania; Philadelphia PA
2. Department of Biostatistics and Epidemiology; Perelman School of Medicine, University of Pennsylvania; Philadelphia PA
3. Leonard Davis Institute of Health Economics; University of Pennsylvania; Philadelphia PA
4. HealthCore, Inc.; Wilmington DE
5. Division of Pulmonary, Allergy, and Critical Care; Department of Medicine; University of Pennsylvania; Philadelphia PA