1. Department of Medicine, Yale University, New Haven, Connecticut, USA
2. Department of Medicine, VA-CT Healthcare System, West Haven, Connecticut, USA
3. Department of Medicine, Division of Gastroenterology and Hepatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
4. Department of Medicine, Gastroenterology Section, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, Pennsylvania, USA