1. Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital Harvard Medical School Boston Massachusetts USA
2. Centre for Clinical Epidemiology Lady Davis Institute, Jewish General Hospital Montreal Québec Canada
3. Department of Medicine McGill University Montreal Québec Canada
4. Division of Rheumatology Jewish General Hospital Montreal Québec Canada
5. Department of Epidemiology, Biostatistics, and Occupational Health McGill University Montreal Québec Canada