1. British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC V6Z 1Y6, Canada
2. Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
3. Department of Educational & Counselling Psychology & Special Education, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
4. Centre for Health Evaluation and Outcome Sciences, Providence Health Care, Vancouver, BC V6Z 1Y6, Canada
5. Department of Family Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada