1. Division of Nephrology, University of Campania, Luigi Vanvitelli, Italy
2. Department of Medicine, VA San Diego Healthcare System and University of California at San Diego Medical School, San Diego, CA, USA
3. Medical Statistics Unit, University of Campania, Luigi Vanvitelli, Italy
4. Department of Internal and Experimental Medicine “Magrassi - Lanzara”, University of Campania, Luigi Vanvitelli, Italy
5. Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
6. Nephrology Unit, University Hospital “San Giovanni di Dio e Ruggi d'Aragona”, Salerno, Italy