[1] Brown Univ, Sch Publ Hlth, Ctr Gerontol & Healthcare Res, Box G-5121 6, Providence, RI 02912 USA
[2] Providence VA Med Ctr, Providence, RI USA
[3] Brown Univ, Warren Alpert Med Sch, Providence, RI 02912 USA
[4] Brown Univ, Sch Publ Hlth, Dept Hlth Serv Policy & Practice, Providence, RI 02912 USA