1. Clinical Research Center for Rheumatoid Arthritis (CRCRA), Seoul, Korea.
2. Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea.
3. Department of Rheumatology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.
4. Department of Rheumatology, Catholic University of Daegu, School of Medicine, Daegu, Korea.
5. Department of Rheumatology, Jeju National University Hospital, Jeju, Korea.
6. Department of Rheumatology, Ajou University Hospital, Suwon, Korea.
7. Department of Rheumatology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea.
8. Department of Rheumatology, Hanyang University Guri Hospital, Guri, Korea.
9. Department of Rheumatology, Chungnam National University Hospital, Daejeon, Korea.
10. Department of Rheumatology, Inje University Ilsan Paik Hospital, Goyang, Korea.
11. Department of Rheumatology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
12. Department of Rheumatology, Dong-A University Hospital, Busan, Korea.
13. Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Korea.
14. Department of Rheumatology, Kyung Hee University Hospital, Seoul, Korea.
15. Department of Rheumatology, Ewha Womans University Mokdong Hospital, Seoul, Korea.
16. Department of Rheumatology, Eulji University Hospital, Daejeon, Korea.
17. Department of Rheumatology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.
18. Department of Rheumatology, Hallym University College of Medicine, Seoul, Korea.