Increased hepatic expression of dipeptidyl peptidase 4 (DPP4) and high serum DPP4 activity have been demonstrated to be associated with NAFLD (10, 11), and NAFLD has been reported to be an independent predictor of the effect of sitagliptin (STG), an oral DPP4 inhibitor, in patients with T2DM (12). Here, DPP4 is linked to type 2 diabetes mellitus.