[1] Duke Univ, Sch Med, Dept Med, Durham, NC USA
[2] Duke Univ, Sch Med, Duke Clin Res Inst, Durham, NC USA
[3] North Carolina State Lab Publ Hlth, North Carolina Dept Hlth & Human Serv, Raleigh, NC USA
[4] Healthspring Global Inc, Bradenton, FL USA
[5] Duke Global Hlth Inst, Durham, NC USA
[6] Duke Univ, Hubert Yeargan Ctr Global Hlth, Durham, NC USA
[7] Duke Univ, Sanford Sch Publ Policy, Durham, NC USA
[8] Duke Univ Lib, Med Ctr, Durham, NC USA
[9] Duke Univ, Sch Med, Dept Biostat & Bioinformat, Durham, NC USA
[10] Duke Univ, Duke Canc Inst, Sch Med, Durham, NC USA
[11] Univ N Carolina, Ctr Hlth Equ Res, Chapel Hill, NC USA
[12] Univ North Carolina Chapel Hill, Dept Social Med, Chapel Hill, NC USA
[13] Univ North Carolina Chapel Hill, Dept Med, Chapel Hill, NC USA
[14] Univ North Carolina Chapel Hill, Dept Internal Med, Chapel Hill, NC USA
[15] Duke Univ, Sch Med, Dept Pediat, Durham, NC USA
[16] Duke Univ, Sch Med, Dept Pathol, Durham, NC 27710 USA