Division of Nephrology, Department of Medicine, Koc University School of Medicine, Istanbul, Turkey. Department of Medicine, Koc University School of Medicine, Istanbul, Turkey. Division of Nephrology, Department of Medicine, Suleyman Demirel University School of Medicine, Isparta, Turkey. IIS-Fundacion Jimenez Diaz, Department of Medicine, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain. Department of Nephrology, Rigshospitalet, Copenhagen, Denmark. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. Department of Nephrology, Grigore T. Popa' University of Medicine, Iasi, Romania. Nephrology Clinic, Dialysis and Renal Transplant Center, 'C.I. Parhon' University Hospital, Iasi, Romania. Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece. Steno Diabetes Center Copenhagen, Copenhagen Denmark and University of Copenhagen, Copenhagen, Denmark.