[1] VA Med Ctr, Dept Internal Med, Durham, NC USA
[2] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Hlth Policy & Management, Chapel Hill, NC USA
[3] Harvard Med Sch, Dept Populat Med, Boston, MA USA
[4] Harvard Pilgrim Hlth Care Inst, Boston, MA USA
[5] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Hlth Behav, Chapel Hill, NC USA
[6] Univ N Carolina, Lineberger Comprehens Canc Ctr, Chapel Hill, NC USA