1. HIRA Research Institute, Health Insurance Review & Assessment Service, Wonju, Korea.
2. Department of Family Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Department of Family medicine, Seoul National University College of Medicine, Seoul, Korea.
4. National Emergency Medical Center, National Medical Center, Seoul, Korea.
5. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
6. Department of Health Policy and Management, Seoul National University College of Medicine, Seoul, Korea.
7. Public Healthcare Center, Seoul National University Hospital, Seoul, Korea.