1 Division of Nephrology and Hypertension, 1st Department of Internal Medicine, AHEPA Hospital, School of Medicine, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece.
2 Faculty of Medicine, University of Nis, 18000 Nis, Serbia.
3 Department of Nephrology, School of Medicine, University of Ioannina, Ioannina, Greece.