[1] Univ British Columbia, Dept Med, Vancouver, BC, Canada
[2] Univ British Columbia, Dept Family Med, Vancouver, BC V5Z 1M9, Canada
[3] Univ Calgary, Fac Nursing, Calgary, AB, Canada
[4] Univ Calgary, Dept Community Hlth Sci, Calgary, AB, Canada
[5] St Pauls Hosp, Ctr Hlth Evaluat Outcomes Sci, Vancouver, BC V6Z 1Y6, Canada