[1] St Michaels Hosp, Dept Family & Community Med, Toronto, ON M5B 1W8, Canada
[2] Univ Toronto, Dept Family & Community Med, Toronto, ON M5S 1A1, Canada
[3] St Michaels Hosp, Ctr Res Inner City Hlth, Keenan Res Ctr, Li Ka Shing Knowledge Inst, Toronto, ON M5B 1W8, Canada
[4] Inst Clin Evaluat Sci, Toronto, ON, Canada
[5] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON M5S 1A1, Canada
[6] Univ Toronto, Dept Med, Toronto, ON M5S 1A1, Canada