Sungkyunkwan University - Department of Medicine, Gyeongsang National University - Department of Medicine, Sungkyunkwan University - Division of Hematology-Oncology, Ajou University - Department of Medicine, Dong-A University - Department of Medicine, Chung-Ang University, College of Medicine, Department of Medicine, Catholic University of Korea - Department of Medicine, Inje University - Department of Medicine, Konkuk University - Department of Medicine, Yonsei University - Department of Medicine, Catholic University of Korea - Department of Medicine, Sungkyunkwan University - Statistics and Data CenterSungkyunkwan University - Department of Ophthalmology, Sungkyunkwan University - Statistics and Data Center, Sungkyunkwan University - Department of Medicine, Sungkyunkwan University - Department of Medicine and Sungkyunkwan University - Department of Medicine