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