1. Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
2. Department of Rheumatology, Coimbra University Hospital, Coimbra, Portugal
3. Department of Rheumatology, Zuyderland Medical Center, Herleen, The Netherlands
4. Department of Rheumatology, Tours University, Tours
5. Department of Rheumatology, Paris Descartes University, Hôpitaux de Paris and
6. INSERM (U1153), Clinical Epidemiology and Biostatistics, PRES Sorbonne Paris-City, Paris, France