INS and diabetes mellitus: This prospective observational study increases the attention and focus on the effect of antihyperglycemic drugs and diet on EF, in subjects with diabetes or pre DM, above all regarding the role of new classes (DPP4i, GLP1a, SGLT2i), showing that there was a higher prevalence of preDM in the diet group compared to the total group, a shorter DM history together with lower HbA1c mean values in the diet group, and a longer DM history together with higher HbA1c mean values in the insulin group, both compared to the total group.