1. Department of Internal Medicine, Seoul Medical Center, Seoul, Korea
2. Division of Rheumatology, Department of Internal Medicine, Wonkwang University Hospital, Iksan, Korea
3. Division of Rheumatology, Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea
4. Division of Rheumatology, Department of Internal Medicine, Kyung Hee University Hospital, Seoul, Korea
5. Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
6. Division of Rheumatology, Department of Internal Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea