DPP4 and type 2 diabetes mellitus: Henceforth, this study result is comparable with the CAROLINA study, an ongoing long-term actively controlled study of linagliptin and glimepiride in patients with T2DM.[40] Fourth, in this study, about 5 years’ worth of NHIS data were used, with a mean follow-up period of 2.1 years for the 5 DPP-4 inhibitors, including the recently introduced DPP-4 inhibitor gemigliptin.