1. Rheumatism Center, Department of Internal Medicine, Inha University College of Medicine, Incheon, Korea
2. Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea
3. Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Korea
4. Division of Rheumatology, Regional Rheumatoid and Degenerative Arthritis Center, Chungnam National University Hospital, Daejeon, Korea