1 Instituto de Investigación Sanitaria de Santiago, Division of Rheumatology, Santiago University Clinical Hospital, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain.
2 University of Cantabria School of Medicine-IDIVAL-CIBERESP, Avenida Herrera Oria s/n, 39011 Santander, Spain.