1. Department of Medicine, Dongguk University-Seoul, Seoul, South Korea.
2. Department of Family Medicine, Dongguk University Ilsan Hospital, Goyang si, South Korea.
3. Department of Palliative Medicine, Tohoku University School of Medicine, Sendai, Japan.
4. Department of Statistics, Dongguk University-Seoul, Seoul, South Korea.
5. Department of Family Medicine, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan.
6. Division of Palliative and Supportive Care, Seirei Mikatahara General Hospital, Hamamatsu, Japan.
7. Department of Family Medicine, Kaohsiung Medical University Hospital, and School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
8. Division of Psychiatry, Marie Curie Palliative Care Research Department, University College London, London, United Kingdom.
9. Division of Palliative Care, Konan Medical Center, Kobe, Japan.
10. Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
11. Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA.
12. Department of Family Medicine, School of Medicine, Catholic Kwandong University International St. Mary's Hospital, Incheon, South Korea.
13. Department of Family Medicine, Chungnam National University School of Medicine, Daejeon, South Korea.
14. Department of Family Medicine, Ilsan-Paik Hospital, College of Medicine, Inje University, Goyang, Korea.
15. Department of Family Medicine, Eunpyeong St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea.