[1] Hosp Gen de Vic, Rheumatol Unit, Vic 08500, Barcelona, Spain
[2] Univ Autonoma Barcelona, Hosp del Mar, Dept Internal Med, E-08193 Barcelona, Spain
[3] Hosp Gen de Vic, Dept Clin Epidemiol, Vic 08500, Barcelona, Spain
[4] Cetir Med Ctr, Nucl Med Serv, Barcelona, Spain
[5] Univ Autonoma Barcelona, Hosp del Mar, Dept Rheumatol, E-08193 Barcelona, Spain