1. Department of Medicine, Division of Infectious Diseases, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania , USA
2. Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania , USA
3. Department of Medicine, Division of Gastroenterology, University of California San Francisco , San Francisco, California , USA
4. Department of Infectious Disease, Cleveland Clinic, Cleveland Clinic Lerner College of Medicine , Cleveland, Ohio , USA
5. Department of Medicine, Division of Gastrointestinal and Liver Diseases, University of Southern California , Los Angeles, California , USA
6. Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine at UCLA , Los Angeles, California , USA
7. Department of Medicine, Section of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Chicago , Chicago, Illinois , USA