[1] Kuopio Univ Hosp, Dept Internal Med, SF-70210 Kuopio, Finland
[2] Oulu Univ Hosp, Dept Internal Med, Oulu, Finland
[3] Finnish Registry Kidney Dis, Helsinki, Finland
[4] Univ Helsinki, Cent Hosp, Div Nephrol, Dept Med, Helsinki, Finland
[5] Univ Tampere, Sch Publ Hlth, FIN-33101 Tampere, Finland