1. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
2. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
3. Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea
4. Department of Internal Medicine, Konyang University School of Medicine, Daejeon, Korea
5. Department of Internal Medicine, St. Vincent’s Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea