1. Department of Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
2. Department of Medicine, Faculty of Medicine, Division of Respirology, University of Ottawa, Ottawa, Ontario, Canada
3. Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada
4. Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
5. Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada