1. Department of Clinical and Experimental Medicine (L.Z., A.G., L.LC., L.F., M.C., L.M., P.C.), University of Catania, Italy.
2. Department of Clinical Biochemistry, Royal Free Hospital campus, University College London, United Kingdom (D.P.M.).
3. Diabetes Center, Division of Endocrinology and Metabolism, First Department of Internal Medicine, AHEPA University Hospital, Thessaloniki, Greece (N.K.).
4. Eye Clinic (N.C., A.L.), University of Catania, Italy.
5. Internal Medicine, St Elia Hospital, Caltanissetta, Italy (G.G.).
6. Nephrology and Dialysis Unit, Giovanni Paolo II Hospital, Ragusa, Italy (C.S.).
7. Infectious Diseases, Giovanni Paolo II Hospital, Ragusa, Italy (F.M., M.A.D.R.).
8. Infectious Diseases, Policlinico di Catania, Italy (A.M.).