[1] Univ Calif Los Angeles, David Geffen Sch Med, Div Gen Internal Med & Hlth Serv Res, Los Angeles, CA 90095 USA
[2] RAND Corp, Santa Monica, CA USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Vatche & Tamar Manoukian Div Digest Dis, Los Angeles, CA 90095 USA
[4] Univ Calif Los Angeles, David Geffen Sch Med, Dept Med, Los Angeles, CA 90095 USA
[5] Univ Calif Los Angeles, David Geffen Sch Med, Div Geriatr, Los Angeles, CA 90095 USA
[6] Vet Affairs VA Greater Los Angeles Healthcare Sys, Los Angeles, CA USA