1. Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea.
2. Clinical Research Center for Rheumatoid Arthritis (CRCRA), Seoul, Korea.
3. Kyung Hee University Medical Center, Seoul, Korea.
4. Hanyang University Guri Hospital, Guri, Korea.
5. Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Catholic University of Daegu School of Medicine, Daegu, Korea.
7. Dong-A University Hospital, Busan, Korea.
8. Chonnam National University Hospital, Gwangju, Korea.
9. Ewha Womans University Mokdong Hospital, Seoul, Korea.
10. Chungnam National University Hospital, Daejeon, Korea.
11. Inje University Ilsan Paik Hospital, Goyang, Korea.