Large swings in blood sugar could harm the heart in type 1 diabetes

Researchers from the University of Michigan have shown that a wider variance in blood glucose results may lead to increased risk of heart problems in people with type 1 diabetes.
The research team monitored 44 patients with type 1 diabetes using continuous glucose monitors. The participants had above target HbA1c levels, an average of 8% (64 mmol/mol) but no signs of heart disease, high cholesterol or high blood pressure. Glucose level data was taken for 5 days and cardiovascular autonomic neuropathy (damage to the nerves of the heart) was measured using cardiovascular reflex testing and heart rate variability.
The researchers found that a higher variability in glucose levels that resulted in hypoglycemia was associated with reduced heart rate variability, which is associated with higher rates of mortality.
The study suggests that wide swings in blood glucose levels resulting in hypoglycemia puts stress upon the heart and may lead to an increased risk of heart problems later in life. The researchers found that the increased risk associated with swings in blood sugar existed independently of HbA1c levels. It is important to note that higher HbA1c levels are associated with greater risk of heart disease too.
Heart disease is one of the main complications of type 1 diabetes. The study suggests that when aiming to reduce HbA1c, it is important to ensure that this is not done in a way that increases hypo severity or increases the time spent with low blood glucose levels.