[1] McGill Univ, Ctr Hlth, Dept Med, Div Clin Immunol Allergy, Montreal, PQ H3A 1A1, Canada
[2] McGill Univ, Ctr Hlth, Dept Med, Div Clin Epidemiol, Montreal, PQ H3A 1A1, Canada
[3] Univ Calif San Francisco, Div Rheumatol, Dept Med, San Francisco, CA 94143 USA
[4] McGill Univ, Dept Epidemiol & Biostat, Montreal, PQ H3A 1A1, Canada
[5] Bristol Myers Squibb Co, Global Epidemiol & Outcomes Res, Princeton, NJ USA