INS and type 2 diabetes mellitus: Patients were divided into five groups: 1) No T2DM (n = 2,603); 2) T2DM on oral hypoglycaemic agents (OHA) including metformin (n = 251); 3) T2DM OHA not including metformin (n = 148); 4) T2DM on insulin (n = 89); 5) T2DM – diet controlled (n = 126).