[1] Univ Calif Irvine, Dept Med, Div Gen Internal Med, iTEQC Res Program, 100 Theory,Suite 120, Irvine, CA 92617 USA
[2] Univ Calif Los Angeles, Borun Ctr, David Geffen Sch Med, Los Angeles, CA USA
[3] Vet Adm GRECC, Los Angeles, CA USA
[4] RAND Hlth, Santa Monica, CA USA
[5] Univ Chicago, Dept Publ Hlth Sci, Chicago, IL USA