Aims: The effect of sitagliptin on the 2-year progression of the arterial stiffness and also to determine the effect of good glycemic control on the rate of progression of the arterial stiffness was examined.

Methods: The study participants were either allocated to add-on sitagliptin treatment or to continued treatment with conventional anti-diabetic agents. We succeeded in measuring the brachial-ankle pulse wave velocity (baPWV) at least two times during the 2-year study period in 96 subjects.

Results: The changes in the baPWV during the study period were similar between the both groups, overall. On the other hand, when the study subjects were divided into two groups according to the glycemic control status during the study period {good glycemic control group (GC) = hemoglobin (Hb)A1c < 7.0 at both 12 and 24 months after the treatment randomization poor glycemic control group (PC) = HbA1c ≥ 7.0 at either 12 months, 24 months, or both}, the 2-year increase of the baPWV was significantly larger in the PC group (144 235 cm/sec) as compared to that the GC group (−10 282 cm/sec) (p = 0.036).

Conclusion: While the present study could not confirm the beneficial effect of sitagliptin per se on the arterial stiffness, the results suggested that good glycemic control may be beneficial for delaying the annual progression of the arterial stiffness.