[1] Univ Calif San Francisco, Dept Med, Div Gen Internal Med, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, San Francisco Gen Hosp, Ctr Vulnerable Populat, San Francisco, CA 94143 USA
[3] Kaiser Permanente No Calif, Div Res, Oakland, CA USA
[4] Univ Washington, Sch Publ Hlth & Community Hlth, Seattle, WA 98195 USA
[5] Univ Calif San Francisco, Ctr Hlth & Community, San Francisco, CA 94143 USA
[6] Kaiser Fdn Hlth Plan, Internet Serv Grp, Oakland, CA USA