[1] MCMASTER UNIV,DEPT MED,HAMILTON L8S 4L8,ONTARIO,CANADA
[2] MCMASTER UNIV,DEPT CLIN EPIDEMIOL & BIOSTAT,HAMILTON L8S 4L8,ONTARIO,CANADA
[3] WELLESLEY HOSP,RHEUMAT DIS UNIT,TORONTO M4Y 1J3,ONTARIO,CANADA
[4] UNIV TORONTO,DEPT MED,TORONTO M5S 1A1,ONTARIO,CANADA
[5] UNIV TORONTO,DEPT HLTH ADM,TORONTO M5S 1A1,ONTARIO,CANADA