[1] VA Hlth Syst San Francisco, San Francisco, CA USA
[2] Leiden Univ, Med Ctr, Leiden, Netherlands
[3] Harvard Med Sch, Massachusetts Gen Hosp, Boston, MA USA
[4] Univ Calif San Francisco, San Francisco, CA USA
[5] Vrije Univ Brussel VUB, End Life Care Res Grp, Brussels, Belgium
[6] Univ Ghent, Ghent, Belgium