It was reported previously that GLP-1 reduced HbA1c levels to a greater extent than did DPP-4 inhibitors [32]–[33], yet data in this article showed no difference between DPP-4 inhibitors and GLP-1 in severe renal dysfunction while a relatively poorer reducing effect of DPP-4 inhibitors was indeed observed in moderate renal dysfunction. This evidence concerns the gene GLP1R and Abnormal renal physiology.