[1] Brown Univ, Warren Alpert Med Sch, Providence, RI 02912 USA
[2] Brown Univ, Dept Hlth Serv, Providence, RI 02912 USA
[3] Brown Univ, Dept Policy & Practice, Providence, RI 02912 USA
[4] Brown Univ, Dept Biostat, Providence, RI 02912 USA
[5] Brown Univ, Vet Affairs Med Ctr, Providence, RI 02912 USA