[1] Univ Calif San Francisco, Dept Med, Div Hosp Med, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Psychiat, San Francisco, CA 94143 USA
[4] Univ Massachusetts, Sch Publ Hlth & Hlth Sci, Amherst, MA USA
[5] Ctr Qual Care Res, Baystate Med Ctr, Springfield, MA USA
[6] Tufts Univ, Sch Med, Dept Med, Boston, MA 02111 USA