In another randomized controlled study, compared with the metformin-glimepiride combination (metformin- sulphonylureas), the combination of metformin-gemigliptin (metformin-DPP-4 inhibitor) achieved more effective glycemic control in T2D patients without increasing the risk of hypoglycemia or weight gain, which may be related to improvements in gut microbiota (108). This evidence concerns the gene DPP4 and type 2 diabetes mellitus.