[1] Kingston Gen Hosp, Clin Evaluat Res Unit, Kingston, ON K7L 2V7, Canada
[2] McMaster Univ, Dept Med, Hamilton, ON, Canada
[3] McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[4] Univ Alberta, Fac Med & Dent, Div Crit Care Med, Edmonton, AB, Canada
[5] Univ Manitoba, Dept Med, Winnipeg, MB, Canada
[6] Univ Manitoba, Dept Community Hlth Sci, Winnipeg, MB R3T 2N2, Canada
[7] Univ Calgary, Dept Crit Care Med, Inst Publ Hlth, Calgary, AB, Canada
[8] Alberta Hlth Serv Calgary Zone, Calgary, AB, Canada
[9] Univ Toronto, Mt Sinai Hosp, Interdept Div Crit Care Med, Toronto, ON M5G 1X5, Canada
[10] St Pauls Hosp, Div Crit Care Med, Vancouver, BC V6Z 1Y6, Canada
[11] St Pauls Hosp, Ctr Hlth Evaluat & Outcome Sci, Vancouver, BC V6Z 1Y6, Canada
[12] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[13] Univ Toronto, St Michaels Hosp, Interdept Div Crit Care, Toronto, ON, Canada
[14] Queens Univ, Dept Crit Care Med, Kingston, ON, Canada
[15] Univ Laval, CHU Quebec Res Ctr, Dept Anesthesiol & Crit Care Med, Quebec City, PQ, Canada
[16] Univ Laval, CHU Quebec Res Ctr, Populat Hlth & Optimal Hlth Practices Res Unit, Quebec City, PQ, Canada
[17] Univ Toronto, Sunnybrook Hosp, Interdept Div Crit Care Med, Toronto, ON, Canada