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.