Vagus Nerve Stimulation & Blood Sugar Control in Diabetes

What Was This Study About?

Many people with diabetes develop a condition called autonomic neuropathy — nerve damage that affects automatic body functions like digestion and heart rate. This damage can also make blood sugar levels harder to control and more unpredictable. Researchers wanted to find out if a non-invasive treatment called transcutaneous vagus nerve stimulation (tVNS) — which uses a small device to gently stimulate a major nerve in the neck through the skin — could help stabilize blood sugar levels in people with this complication.

How Was the Study Done?

The trial enrolled 145 people with diabetes (70 with Type 1, 75 with Type 2) who also had autonomic neuropathy. Participants were randomly assigned to either:

• Active tVNS: Real nerve stimulation using the device
• Sham (fake) stimulation: A device that felt similar but delivered no real stimulation

Participants used the device themselves at home — 4 times daily for 1 week, then 2 times daily for 8 weeks, with a rest period in between. Blood sugar was tracked continuously using CGM (Continuous Glucose Monitoring) sensors throughout the study. Researchers looked at two main measurements:

• Coefficient of Variation (CV): How much blood sugar fluctuates up and down
• Time in Range (TIR): How many hours per day blood sugar stays within a healthy target zone

What Did the Results Show?

Overall, the study found no significant difference between the active tVNS group and the sham group in blood sugar variability or time in range — for either the 1-week or the 8-week treatment periods. However, there was one notable finding in a subgroup:

• People with Type 1 diabetes who used active tVNS for 8 weeks showed a significant reduction in blood sugar variability (CV) compared to the Type 1 sham group. Their estimated improvement was about 11.6% less variability.

No significant changes were seen in HbA1c or other secondary measurements between groups.

What Does This Mean for Patients?

This study suggests that vagus nerve stimulation does not broadly improve blood sugar control in all people with diabetes and autonomic neuropathy. However, the finding in Type 1 diabetes patients is intriguing and warrants further investigation in larger, longer studies. If you have Type 1 diabetes and autonomic neuropathy and struggle with unpredictable blood sugar swings, this research — while early — hints that tVNS could one day be a helpful add-on therapy. For now, speak with your diabetes care team about the best strategies for managing glucose variability.