1. Clinical Epidemiology Program, Ottawa Hospital Research Institute
2. Department of Anesthesiology and Pain Medicine, Faculty of Medicine, University of Ottawa
3. Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa
4. Department of Educational Studies, University of South Carolina
5. Keele Cardiovascular Research Group, Centre for Prognosis Research, Keele University, Keele, UK
6. Institute for Clinical Evaluative Sciences, Ontario, Canada
7. Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA