1. Department of Internal Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea
2. Department of Internal Medicine, Chungbuk National University Hospital, Cheongju, Korea
3. Department of Internal Medicine, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea
4. Department of Internal Medicine, Jeju National University College of Medicine, Jeju, Korea