1 Division of Medicine and Hepatology, University Hospital of Messina, Italy.
2 Division of Medicine and Hepatology, University Hospital of Messina, Italy; Department of Clinical and Experimental Medicine, University of Messina, Italy.
3 Unit of Statistical and Mathematical Sciences, Department of Economics, University of Messina, Italy.
4 Division of Medicine and Hepatology, University Hospital of Messina, Italy; Department of Clinical and Experimental Medicine, University of Messina, Italy. Electronic address: raimondo@unime.it.