[1] Gunma Univ, Dept Healthcare Qual & Safety, Grad Sch Med, Maebashi, Gunma, Japan
[2] Kyoto Univ, Dept Nephrol, Grad Sch Med, Kyoto, Japan
[3] St Lukes Int Hosp, Dept Nephrol, Tokyo, Japan
[4] Tokyo Med Univ, Dept Med, Div Gen Internal Med, Ibaraki Med Ctr, Ibaraki, Japan
[5] St Lukes Int Hosp, Div Gen Internal Med, Dept Med, Tokyo, Japan
[6] Ohta Nishinouchi Hosp, Dept Gen Internal Med, Koriyama, Fukushima, Japan