[1] Niigata Univ, Sch Med, Dept Internal Med 3, Niigata 9518510, Japan
[2] Ken Ritsu Tyu Oh Hosp, Joh Etsu, Japan
[3] Shinrakuen Hosp, Niigata, Japan
[4] Niigata City Hosp, Niigata, Japan
[5] Shibata Prefectural Hosp, Niigata, Japan
[6] Saiseikai Second Hosp, Niigata, Japan
[7] Nippon Dent Univ Hosp, Niigata, Japan
[8] Sanjyo Saiseikai Hosp, Niigata, Japan