1. Department of Clinical Epidemiology and Biostatistics; McMaster University; Hamilton Canada
2. Department of Medicine; McMaster University; Hamilton Canada
3. Clinical Epidemiology Unit, Ottawa Hospital Research Institute; Ottawa Hospital; Ottawa Ontario Canada
4. Bristol Heart Institute; University of Bristol, Bristol Royal Infirmary; Bristol UK
5. Department of Internal Medicine; American University of Beirut; Beirut Lebanon
6. Portland VA Medical Center and Department of Medicine; Oregon Health and Science University; Portland Oregon USA