1. Department of Rheumatology, Hospital at Gangdong Kyung Hee University Seoul Korea
2. Department of Rheumatology Asan Medical Center University of Ulsan College of Medicine Seoul Korea
3. Department of Rheumatology Pusan National University Hospital Pusan Korea
4. Division of Medical Pfizer Biopharmaceuticals Group Pfizer Pharmaceuticals Korea Limited Seoul Korea
5. Department of Biostatistics College of Medicine Korea University Seoul Korea
6. Department of Rheumatology Hanyang University Hospital for Rheumatic Diseases Seoul Korea