[1] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Sch Pharm, Div Pharmaceut Outcomes & Policy, Chapel Hill, NC 27599 USA
[3] Vet Affairs Maryland Hlth Care Syst, Baltimore, MD USA
[4] Acon Res Ltd, Div Hlth Econ, Ft Worth, TX USA
[5] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD USA
[6] Univ Maryland, Sch Med, Baltimore, MD 21201 USA
[7] Johns Hopkins Univ, Sch Med, Dept Ophthalmol, Baltimore, MD 21205 USA
[8] Univ N Carolina, Sch Pharm, Chapel Hill, NC USA
[9] Husson Coll, Bangor, ME USA