[1] Duke Univ, Sch Med, Duke Clin Res Inst, Durham, NC 27710 USA
[2] Duke Univ, Sch Med, Dept Med, Div Cardiol, Durham, NC 27710 USA
[3] Duke Univ, Sch Med, Dept Populat Hlth Sci, Durham, NC 27710 USA
[4] Wake Forest Univ, Bowman Gray Sch Med, Dept Epidemiol & Prevent, Winston Salem, NC USA
[5] Univ Mississippi, Med Ctr, Dept Med, Div Cardiol, Jackson, MS USA
[6] Univ Mississippi, Med Ctr, Dept Med, Jackson, MS 39216 USA