[1] Univ Penn, Sch Nursing, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[2] Univ Penn, Sch Nursing, Ctr Hlth Outcomes Res & Policy, Philadelphia, PA 19104 USA
[3] Univ Kentucky, Coll Nursing, Lexington, KY USA
[4] Minneapolis Vet Adm Med Ctr, Ctr Chron Dis Outcomes Res, Minneapolis, MN USA
[5] Univ Colorado, Denver Hlth Med Ctr, Denver, CO 80202 USA