[1] Gen Hosp Alexandroupoli, Dept Nephrol, Alexandroupolis, Greece
[2] Pieria, Hemodialysis Unit, Katerini, Greece
[3] Protypo, Hemodialysis Unit, Thessaloniki, Greece
[4] Therapeutiki, Hemodialysis Unit, Thessaloniki, Greece
[5] Aristotle Univ Thessaloniki, Hippokrat Hosp, Dept Nephrol, Thessaloniki, Greece
[6] Aristotle Univ Thessaloniki, AHEPA Hosp, Sect Nephrol & Hypertens, Dept Nephrol,Dept Med 1, Thessaloniki, Greece