[1] VAMC, Ctr Hlth Serv Res Primary Care, Durham, NC 27710 USA
[2] Duke Univ, Med Ctr, Div Gen Internal Med, Durham, NC 27706 USA
[3] St Pauls Hosp, Ctr Hlth Evaluat & Outcome Sci, Vancouver, BC, Canada
[4] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[5] Purdue Univ, W Lafayette, IN 47907 USA
[6] Duke Univ, Med Ctr, Div Biometry & Bioinformat, Durham, NC USA
[7] Emory Univ, Atlanta VAMC, Atlanta, GA 30322 USA
[8] Emory Univ, Nell Hodgson Woodruff Sch Nursing, Atlanta, GA 30322 USA
[9] Pittsburgh VAMC, Pittsburgh, PA USA
[10] St Louis VAMC, St Louis, MO USA
[11] Hunter Holmes McGuire VA Med Ctr, Richmond, VA USA