1. Nephrology and Dialysis Unit, Department of Medicine, San Salvatore Hospital, Via Vetoio, 67100 L’Aquila, Italy
2. Department of Medicine and Surgery, Centro di Ricerca Clinica e Traslazionale, CERICLET, University of Perugia, 06126 Perugia, Italy
3. Nephrology and Dialysis Unit, Department of Medicine, S. Maria della Misericordia Hospital, 06156 Perugia, Italy
4. Dialysis Unit, Department of Medicine, Maria SS. dello Splendore Hospital, Viale Gramsci, 64021 Giulianova, Italy
5. Nephrology and Dialysis Unit, Department of Medicine, G. d’Annunzio University, Chieti-Pescara, SS. Annunziata Hospital, Via dei Vestini, 66013 Chieti, Italy