[1] Stanford Univ, Dept Med, Stanford, CA USA
[2] Stanford Univ, Sch Med, Stanford, CA USA
[3] VA Palo Alto Hlth Care Syst, Palo Alto, CA USA
[4] Stanford Univ, Dept Hlth Policy, Stanford, CA USA
[5] David Geffen Sch Med, Div Gen Internal Med & Hlth Serv Res, Los Angeles, CA USA
[6] Keio Univ, Dept Cardiol, Sch Med, Tokyo, Japan
[7] Stanford Univ, VA Palo Alto Hlth Care Syst, 870 Quarry Rd Extens, Palo Alto, CA 94304 USA