1. Division of Rheumatology, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
2. Samsung Biomedical Research Institute, Seoul, Korea
3. Department of Internal Medicine, Samsung Changwon Hospital, Changwon, Korea
4. Department of Internal Medicine, National Medical Center, Seoul, Korea
5. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea