1. Department of Medicine, Kingston General Hospital, Kingston, Ontario, Canada, Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada, Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, Ontario, Canada,
2. Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
3. Department of Medicine, Queen Elizabeth Health Sciences Center, Halifax, Nova Scotia, Canada
4. Program in Critical Care Medicine and Center for Health Evaluation and Outcome Sciences, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
5. Department of Public Health Sciences and Division of Critical Care Medicine, University of Alberta, Edmonton, Alberta, Canada
6. Critical Care, Hôpital Maisonneuve-Rosemont, Université de Montréal, Québec, Canada
7. Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, Ontario, Canada
8. Departments of Oncology and Medicine, McGill University and Jewish General Hospital, Montreal, Quebec, Canada