DPP4 and type 2 diabetes mellitus: The main findings of this study are the following: (1) the activity of circulating DPP4 is abnormally increased in patients with T2DM; (2) increased activity of circulating DPP4 is independently associated with asymptomatic LVDD and LVSD in T2DM patients; and (3) T2DM patients with increased activity of circulating DPP4 exhibit a higher risk of presenting LVD independently of the presence of confounding factors.