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