1. Department of Health Administration, Namseoul University, Cheonan, Korea.
2. Institute of Health Services Research, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Hospital Management, Graduate School of Public Health, Yonsei University, Seoul, Korea.
5. Department of Medicine, University of Wisconsin School of Medicine and Public Health, Milwaukee, WI, USA.
6. Center for Senior Health and Longevity, Aurora Health Care, Milwaukee, WI, USA.