1. Health Insurance Review and Assessment Research Institute, Health Insurance Review and Assessment Service
2. Department of Preventive Medicine, Konkuk University School of Medicine
3. Department of Thoracic and Cardiovascular Surgery, The Catholic University of Korea College of Medicine
4. Department of Thoracic and Cardiovascular Surgery, Konkuk University Medical Center, Konkuk University School of Medicine
5. Department of Thoracic and Cardiovascular Surgery, Keimyung University School of Medicine
6. Thoracic and Cardiovascular Surgery, Kangwon National University Hospital