[1] Div Rheumatol, London, ON, Canada
[2] Univ S Florida, Dept Biostat, Tampa, FL USA
[3] Univ Toronto, Mt Sinai Hosp, Div Rheumatol, Toronto, ON, Canada
[4] Vasculitis Fdn, Kansas City, MO USA
[5] Univ Penn, Div Rheumatol, Vasculitis Ctr, Philadelphia, PA 19104 USA