[1] British Columbia Ctr Subst Use, 400-1045 Howe St, Vancouver, BC V6Z 2A9, Canada
[2] Univ British Columbia, Dept Med, Vancouver, BC, Canada
[3] Canadian AIDS Soc, Ottawa, ON, Canada
[4] Yale Sch Med, Gen Internal Med, New Haven, CT USA
[5] Yale Sch Publ Hlth, Social & Behav Sci, New Haven, CT USA