1. Department of Family Medicine, General Practice and Community Health, Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
2. Department of General Medicine, Tsukuba Central Hospital, Ushiku, Ibaraki, Japan.
3. Department of Pharmacy, Tsukuba Central Hospital, Ushiku, Ibaraki, Japan.
4. Department of Palliative and Supportive Care, Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.