[1] David Geffen Sch Med UCLA, Div Gen Internal Med & Hlth Serv Res, Los Angeles, CA 90095 USA
[2] VA Greater Los Angeles Healthcare Syst, Los Angeles, CA USA
[3] David Geffen Sch Med UCLA, Dept Surg, Los Angeles, CA USA
[4] Brigham & Womens Hosp, Div Gen Internal Med & Primary Care, Boston, MA USA
[5] Harvard Univ, T H Chan Sch Publ Hlth, Boston, MA USA
[6] Olive View UCLA Med Ctr, Sylmar, CA USA
[7] Harbor Univ Calif Los Angeles Med Ctr, Dept Surg, Torrance, CA 90509 USA
[8] Assoc Amer Med Coll, Washington, DC USA
[9] Univ Calif Los Angeles, Fielding Sch Publ Hlth, Dept Hlth Policy & Management, Los Angeles, CA USA