1. Department of Rheumatology, Ajou University School of Medicine, Suwon, Korea.
2. Department of Rheumatology, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
3. Department of Rheumatology, Chung-Ang University College of Medicine, Seoul, Korea.
4. Division of Rheumatology, Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea.
5. Department of Medical Humanities and Social Medicine, Office of Biostatistics, Ajou University School of Medicine, Suwon, Korea.