1. 1Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
2. 2Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
3. 3Department of Medical Statistics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
4. 4Department of Statistics and Actuarial Science, Soongsil University, Seoul, Republic of Korea
5. 5Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University, and Liverpool Chest and Heart Hospital, Liverpool, U.K.
6. 6Danish Center for Clinical Health Services Research, Aalborg University, Aalborg, Denmark