[1] Univ Toronto, Dept Med, Toronto, ON, Canada
[2] Univ Toronto, Dept Hlth Policy Management & Evaluat, Toronto, ON, Canada
[3] St Michaels Hosp, Div Respirol, Toronto, ON M5B 1W8, Canada
[4] St Michaels Hosp, Dept Med, Ctr Res Inner City Hlth, Keenan Res Ctr, Toronto, ON M5B 1W8, Canada
[5] St Michaels Hosp, Li Ka Shing Knowledge Inst, Toronto, ON M5B 1W8, Canada
[6] St Michaels Hosp, Div Gen Internal Med, Toronto, ON M5B 1W8, Canada