Long-term blood sugar control may not affect macrovascular atherosclerosis in type 1 diabetes patients: Study

Carotid intima-media thickness is a surrogate marker of atherosclerosis that predicts cardiovascular events, particularly stroke and myocardial infarction. It can be measured using ultrasound of the two innermost layers of the tunica intima, carotid artery wall, and tunica media. Ultrasound of the CIMT provides a reproducible, easy non-invasive tool to evaluate the risk of cardiovascular disease (CVD).

Type 1 diabetes (T1D) is known to increase the risk of cardiovascular disease and T1D patients are at a sixfold increased risk of stroke versus non-diabetic individuals. The researchers note that these patients with T1D have increased CIMT compared to healthy controls. Recent studies have shown that CIMT is a potential indicator of cerebral small vessel disease in patients with T1D, irrespective of blood glucose control. Jussi Inkeri, University of Helsinki, Helsinki, Finland, and colleagues aimed to explore the relationship between CIMT and the current glycemic control, as well as the long-term glycemic control over the preceding ten years, in a well-characterized cohort of Finnish individuals with type 1 diabetes.

For this purpose, the researchers recruited 508 individuals (43.4% men; median age 46) with type 1 diabetes in a cross-sectional retrospective sub-study, part of the Finnish Diabetic Nephropathy (FinnDiane) Study. Data on glycated haemoglobin (HbA1c) was collected retrospectively over ten years (HbA1c-mean overall) before the clinical study visit that included a biochemical sampling, clinical examination, and ultrasound of the common carotid arteries.

The study revealed the following findings:

· Individuals with T1D had a median CIMT of 606 μm and HbA1c of 8.0% during the study visit and HbA1c-meanoverall of 8.0%.

· CIMT did not correlate with HbA1c at visit or HbA1c-meanoverall.

· After controlling for relevant factors in multivariable linear regression analysis, only age was associated with CIMT.

· After further dividing CIMT into quartiles, no correlation between long-term glucose control and CIMT (%, 1st 8.1 versus 4th 7.9) was found.

The main finding of the study was the lack of association between long-term blood glucose control and CIMT in T1D patients.

"The finding was surprising considering previous data showing associations between blood glucose control and CIMT in other cohorts of people with T1D," the researchers wrote. "Only age was independently associated with CIMT, they added, "our findings, thus, suggest that there are other factors involved."

"We hope that our findings will pave the way for future studies that can shed light and further explore the complex interplay of various factors in determining CIMT in T1D," they concluded.

Reference:

Inkeri, J., Harjutsalo, V., Martola, J. et al. No correlation between carotid intima-media thickness and long-term glycemic control in individuals with type 1 diabetes. Acta Diabetol (2023). https://doi.org/10.1007/s00592-023-02211-y