[1] Univ Edinburgh, E Hlth Grp, Ctr Populat Hlth Sci, Edinburgh EH8 9AG, Midlothian, Scotland
[2] Univ Aberdeen, Hlth Econ Res Unit, Aberdeen, Scotland
[3] Edinburgh Hlth Serv Res Unit, Edinburgh, Midlothian, Scotland
[4] Edinburgh Napier Univ, Dept Nursing, Edinburgh, Midlothian, Scotland
[5] Univ Edinburgh, Dept Geriatr Med, Edinburgh EH8 9AG, Midlothian, Scotland
[6] Brigham & Womens Hosp, Div Gen Internal Med & Primary Care, Brigham, MA USA
[7] Harvard Univ, Sch Med, Dept Med, Boston, MA USA