1. Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
2. Division of Rheumatology, Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
3. Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
4. Division of Rheumatology, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
5. Division of Rheumatology, Department of Internal Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea