[1] United BioSource Corp, Ctr Hlth Outcomes Res, Bethesda, MD USA
[2] Pfizer Inc, New York, NY USA
[3] Univ N Carolina, Chapel Hill, NC USA
[4] Univ Gothenburg, Sahlgrenska Acad, Gothenburg, Sweden
[5] Univ Roma La Sapienza, St Andrea Hosp, Rome, Italy
[6] Royal Hallamshire Hosp, Sheffield S10 2JF, S Yorkshire, England
[7] Hosp Univ Penn, Philadelphia, PA 19104 USA