1. Department of Rheumatology and Clinical Immunology, Charité University Medicine, Berlin, Germany
2. Department of Rheumatology and Immunology, Medical University Graz, Graz, Austria
3. Divisions of Rheumatology and Epidemiology, and Departments of Internal Medicine and Health Sciences Research, Mayo Clinic College of Medicine, Rochester, Minnesota
4. Department of Rheumatology, Southend University Hospital, Southend, United Kingdom