Russell J Steele1, Mireille E Schnitzer2, Ian Shrier3. 1. From the Department of Mathematics and Statistics, McGill University, Montreal, QC, Canada. 2. Faculté de pharmacie, Université de Montréal. 3. Centre for Clinical Epidemiology, Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Family Medicine, McGill University, Montreal, QC, Canada.