[1] Vet Affairs Puget Sound Hlth Care Syst, Gen Med Serv, Seattle, WA USA
[2] Vet Affairs Puget Sound Hlth Care Syst, Gastroenterol Serv, Seattle, WA USA
[3] Vet Affairs Puget Sound Hlth Care Syst, Epidemiol Res & Informat Ctr, Seattle, WA USA
[4] Vet Affairs Puget Sound Hlth Care Syst, Gastroenterol Sect, Seattle, WA USA
[5] Vet Affairs Puget Sound Hlth Care Syst, Hlth Serv Res & Dev, Seattle, WA USA
[6] Univ Washington, Sch Med, Div Gen Internal Med, Seattle, WA USA
[7] Univ Washington, Sch Med, Div Gastroenterol, Seattle, WA USA
[8] Portland VA Med Ctr, Gastroenterol Serv, Portland, OR USA
[9] Oregon Hlth & Sci Univ, Div Gastroenterol, Portland, OR 97201 USA
[10] Univ Washington, Sch Publ Hlth, Dept Epidemiol, Seattle, WA 98195 USA
[11] Univ Washington, Sch Publ Hlth, Hlth Serv Dept, Seattle, WA 98195 USA
[12] US Dept Vet Affairs, Off Specialty Care Serv, Vet Hlth Adm, Washington, DC USA