[1] Univ N Carolina, Sch Pharm, Div Pharmaceut Outcomes & Policy, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Chapel Hill, NC 27599 USA
[3] Univ N Carolina, Dept Hlth Policy & Adm, Chapel Hill, NC 27599 USA
[4] Univ Arkansas Med Sci, Div Pharmaceut Evaluat & Policy, Little Rock, AR 72205 USA