[1] VA Palo Alto Hlth Care Syst, VA Cooperat Studies Program Coordinating Ctr, VA HSR&D Hlth Econ Resource Ctr, Menlo Pk, CA 94025 USA
[2] St Michaels Hosp, Li Ka Shing Knowledge Inst, Keenan Res Ctr, Ctr Res Inner City Hlth, Toronto, ON M5B 1W8, Canada
[3] St Michaels Hosp, Div Gen Internal Med, Toronto, ON M5B 1W8, Canada
[4] Univ Toronto, Dept Med, Toronto, ON M5S 1A1, Canada
[5] Univ Toronto, Dept Hlth Policy Management & Evaluat, Toronto, ON M5S 1A1, Canada
[6] Univ York, Ctr Hlth Econ, York YO10 5DD, N Yorkshire, England
[7] St Pauls Hosp, Ctr Hlth Evaluat & Outcome Sci, Vancouver, BC V6Z 1Y6, Canada
[8] Canadian HIV Trials Network, Vancouver, BC, Canada
[9] VA Palo Alto Hlth Care Syst, Palo Alto, CA USA
[10] James J Peters VA Med Ctr, Bronx, NY USA
[11] VA Cooperat Studies Program Coordinating Ctr, West Haven, CT USA
[12] Univ Ottawa, Ottawa Hosp Res Inst, Div Infect Dis, Ottawa, ON, Canada
[13] Royal Free Hosp, London NW3 2QG, England
[14] Univ British Columbia, Dept Hlth Care & Epidemiol, Vancouver, BC V6T 1W5, Canada
[15] Stanford Univ, Ctr Primary Care & Outcomes Res, Stanford, CA 94305 USA