[1] Boston Univ, Sch Med, Gen Internal Med Sect, Boston Med Ctr, Boston, MA 02118 USA
[2] Massachusetts eHlth Collaborat, Waltham, MA USA
[3] Brigham & Womens Hosp, Div Gen Internal Med, Boston, MA 02115 USA
[4] Partners HlthCare Syst Inc, Wellesley, MA USA
[5] Harvard Pilgrim Hlth Care Inst, Boston, MA USA
[6] Dept Populat Med, Boston, MA USA
[7] Harvard Univ, Sch Med, Boston, MA USA
[8] Harvard Univ, Sch Publ Hlth, Boston, MA 02115 USA
[9] VA Boston Healthcare Syst, Gen Internal Med Sect, Boston, MA USA