[1] Kaiser Permanente San Francisco, Dept Gastroenterol, San Francisco, CA USA
[2] Div Res, Kaiser Permanente Northern Calif, Oakland, CA USA
[3] Kaiser Permanente Informat Technol, Pleasanton, CA USA
[4] Harvard Med Sch, Dept Populat Med, Boston, MA USA
[5] Harvard Pilgrim Hlth Care Inst, Boston, MA USA
[6] Beth Israel Deaconess Med Ctr, Div Infect Dis, Boston, MA USA
[7] Dept Adult & Family Med, Kaiser Permanente San Francisco, San Francisco, CA USA
[8] 2238 Geary Blvd, San Francisco, CA 94115 USA