[1] Univ Penn, Perelman Sch Med, Div Gastroenterol & Hepatol, 3400 Civ Ctr Blvd,4th Floor,South Pavil, Philadelphia, PA 19104 USA
[2] Univ Penn, Leonard David Inst Hlth Econ, Philadelphia, PA 19104 USA
[3] Harvard Med Sch, Beth Israel Deaconess Med Ctr, Div Gastroenterol Hepatol & Nutr, Boston, MA 02115 USA
[4] Univ Penn, Perelman Sch Med, Dept Biostat Epidemiol & Informat, Tenter Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[5] Vet Affairs Puget Sound Healthcare Syst, Dept Med, Div Gastroenterol, Seattle, WA USA
[6] Univ Washington, Seattle, WA 98195 USA
[7] Vet Affairs Puget Sound Healthcare Syst, Hlth Serv Res & Dev, Seattle, WA USA
[8] Yale Univ, Sch Med, Div Digest Dis, New Haven, CT USA
[9] VA Connecticut Healthcare Syst, West Haven, CT USA
[10] Corporal Michael J Crescenz VA Med Ctr, Dept Med, Philadelphia, PA USA
[11] Univ Miami, Miller Sch Med, Div Digest Hlth & Liver Dis, Dept Med, Miami, FL 33136 USA