Insulin pump treatment vs. multiple daily insulin injections in patients with poorly controlled Type 2 diabetes mellitus: a comparison of cardiovascular effects

AIMS: Both hyperglycaemia and large glycaemic variability are associated with worse outcomes in patients with Type 2 diabetes mellitus (T2DM), possibly causing sympatho-vagal imbalance and endothelial dysfunction. Continuous subcutaneous insulin injection (CSII) improves glycemic control compared to multiple daily insulin injections (MDI). We aimed to assess whether CSII may improve cardiac autonomic and vascular dilation function compared to MDI. METHODS: We enrolled T2DM patients without cardiovascular disease with poor glycaemic control, despite optimized MDI therapy. Patients were randomized to continue MDI (with multiple daily peripheral glucose measurements) or CSII; insulin dose was adjusted to achieve optimal target ranges of blood glucose levels. Patients were studied at baseline and after 6 months by: 1) flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of the brachial artery; 2) heart rate variability (HRV) by 24-hour ECG Holter monitoring (HM). 7-day continuous glucose monitoring (CGM) was performed in 9 and 8 patients of Group 1 and 2, respectively. RESULTS: Overall, 21 patients were enrolled, 12 randomized to CSII (Group 1) and 9 to MDI (Group 2). The daily dose of insulin and Hb1AC did not differ significantly between the 2 groups, both at baseline and at follow-up. Glucose variability showed some significant improvement at follow-up in the whole population, but no differences were observed between the 2 groups. Both FMD and NMD, as well as HRV parameters, showed no significant differences between the 2 groups at 6-month follow-up. CONCLUSIONS: In this randomized small study we show that, in T2DM patients, CSII achieves a similar medium-term glycemic control compared to MDI, without any adverse effect on the cardiovascular system.