Italian Study: Insulin Pumps vs. Daily Injections — What It Means for Your Heart

A study from Italy examined whether insulin pump therapy offers cardiovascular advantages over multiple daily injections for people with poorly controlled Type 2 diabetes — a question with real implications for the millions of Americans struggling to hit their blood sugar targets.

What the Researchers Did

Scientists at the Department of Cardiovascular Sciences, Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome enrolled 21 adults with Type 2 diabetes (T2DM) who were not meeting their blood sugar goals despite already being on optimized multiple daily injection (MDI) therapy. Patients had no existing cardiovascular disease at the start of the study.

Participants were randomly assigned to one of two groups:

• Group 1 (12 patients): Switched to a continuous subcutaneous insulin infusion pump (CSII), commonly known as an insulin pump
• Group 2 (9 patients): Continued multiple daily injections (MDI) with regular fingerstick glucose monitoring

Both groups were followed for six months. Researchers measured cardiovascular health using two key tools: flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of the brachial artery — both reliable indicators of blood vessel flexibility and health. They also analyzed heart rate variability (HRV) via 24-hour heart monitors, a measure of how well the nervous system regulates the heart. A subset of patients wore continuous glucose monitors (CGMs) for 7-day periods to track glucose swings.

What They Found

After six months, both groups showed similar results across the board:

• HbA1c levels did not differ significantly between groups. For reference, the American Diabetes Association (ADA) recommends an HbA1c below 7% (53 mmol/mol) for most adults — both groups remained above target but showed comparable improvement.
• Glucose variability improved somewhat across the full study population, but there was no significant difference between pump and injection users.
• Blood vessel function (FMD and NMD) showed no meaningful difference between groups.
• Heart rate variability — a marker of cardiac autonomic health — was also similar in both groups.

Importantly, insulin pump therapy did not cause any adverse cardiovascular effects.

US Unit Conversions

Blood glucose targets referenced in this study align with standard US goals. Optimal fasting blood glucose for most US patients with T2DM is 80–130 mg/dL (4.4–7.2 mmol/L), and post-meal glucose should stay below 180 mg/dL (10.0 mmol/L), per ADA 2024 guidelines.

Why This Matters for US Patients

Insulin pump use has traditionally been associated with Type 1 diabetes, but its use in Type 2 is growing in the United States. Many patients and doctors wonder whether making the switch to a pump delivers added cardiovascular benefits — especially since both high blood sugar and glucose swings are known to strain the heart and blood vessels.

This Italian study offers reassurance: switching to a pump in poorly controlled T2DM appears safe from a cardiovascular standpoint. However, it also suggests the pump may not provide a cardiovascular advantage over well-managed daily injections in the short term. For US patients considering a pump primarily for heart health reasons, this study suggests the decision should be based on lifestyle fit, glucose control convenience, and physician guidance — not an assumed cardiac benefit.

One important caveat: the study enrolled only 21 patients, making it too small to draw firm conclusions. Larger US-based trials are needed to confirm these findings.

Study Citation

Tremamunno, Tartaglione, Telesca. Insulin pump treatment vs. multiple daily insulin injections in patients with poorly controlled Type 2 diabetes mellitus: a comparison of cardiovascular effects. Endocrine (2024). PMID: 38197988. DOI: 10.1007/s12020-023-03651-w