1. Department of Internal Medicine, Myongji Hospital, Hanyang University College of Medicine, Goyang, Korea
2. Department of Internal Medicine, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea
3. Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea
4. Department of Internal Medicine, Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Seoul, Korea
5. Department of Internal Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea