1. Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan
2. Department of Nephrology, Saiseikai Kawaguchi General Hospital, Saitama, Japan
3. Saitama Social Insurance Hospital, Saitama, Japan
4. Department of Nephrology, Dokkyo University Koshigaya Medical Center, Saitama, Japan
5. Department of Public Health, Jichi Medical University, Tochigi, Japan
6. Department of Internal Medicine, Mimami-uonuma City Hospital, Niigata, Japan