Insulin analogs as an add-on to metformin after failure to oral treatment in type 2 diabetic patients increase diastole duration. The INSUlin Regimens and VASCular Functions (INSUVASC) study.

BACKGROUND

Fast acting insulin analogues are known to improve arterial stiffness. The combination of metformin with insulin represents a widely used therapeutic strategy in diabetes. We hypothesized that insulin treatment in patients with type 2 diabetes (T2D) with long-acting, fast-acting or basal bolus insulin as an add-on to metformin would provide additional improvement of arterial stiffness.

METHODS

The INSUlin Regimens and VASCular Functions (INSUVASC) study is a pilot, randomized, open label three-arms study that included 42 patients with type 2 diabetes (T2D) in primary prevention, after a failure to oral antidiabetic agents. Arterial stiffness measurements were performed at fasting and after a standardized breakfast. During the first visit (V1) pre-randomization, participants took only metformin to perform the tests. The same tests were repeated after 4 weeks of insulin treatment during the second visit (V2).

RESULTS

Data were available for final analysis in 40 patients, with a mean age of 53.6±9.7 years and a mean duration of diabetes of 10.6±5.6 years. Twenty-one were females (52.5%), hypertension and dyslipidemia were present in 18 (45%) and 17 patients (42.5%), respectively. After insulin treatment, the metabolic control was associated to a decrease in oxidative stress and improvement of endothelial functions, with a post prandial diastole duration increased and a decrease of the peripheral arterial stiffness, with a better post prandial pulse pressure ratio and ejection duration after insulin. In hypertensive patients, insulin treatment provided positive effects by decreasing the pulse wave velocity and improving reflection time.

CONCLUSIONS

A short time treatment by insulin in addition to metformin improved myocardial perfusion. Moreover, insulin treatment in hypertensive patients provides a better hemodynamic profile in large arteries.