1. Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
3. Department of Internal Medicine, The Cathoilc University of Korea College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.