[1] Univ Calif Davis, Dept Pediat, Sch Med, Sacramento, CA 95817 USA
[2] Univ Calif Davis, Div Emergency Med, Dept Internal Med, Sch Med, Sacramento, CA 95817 USA
[3] Univ Calif Davis, Ctr Hlth Serv Res Primary Care, Sch Med, Sacramento, CA 95817 USA