Carotid plaque linked to later cardiovascular events in adults with type 1 diabetes

The study

This is a cohort study published in Cardiovascular Diabetology. It asked whether carotid atherosclerosis predicts future cardiovascular events (CVE) and death in adults with type 1 diabetes (T1D) who had no previous event (primary prevention).

The adults took part in a cardiovascular risk assessment programme that included carotid ultrasound. They were eligible if they were aged 40 years or more, or had diabetic kidney disease at any age or diabetes duration, or had T1D for 10 years or more plus at least one other cardiovascular risk factor.

The primary endpoint was the first CVE. A secondary endpoint combined CVE with death from any cause. The authors used Kaplan-Meier curves and Cox regression models.

What they found

The study followed 701 people for a mean of 5.85 years. Mean age was 48.5 years, mean T1D duration was 27 years, and 51.9% were men. Carotid plaques were present in 40.4%.

During follow-up there were 45 CVE: 18 coronary artery disease, 14 peripheral artery disease, 6 stroke, 3 heart failure and 4 deaths. There were also 5 non-cardiovascular deaths.

Event-free survival fell step by step as plaque burden rose (log-rank p < 0.001).

In unadjusted analyses, any plaque was associated with a higher risk of CVE (HR 3.14, 95% CI 1.69-5.84). It was also associated with a higher risk of the composite endpoint (HR 3.07, 95% CI 1.71-5.51).

After adjustment for demographic, metabolic and microvascular factors, a high plaque burden (3 or more plaques) stayed associated with a higher risk of CVE (HR 3.38, 95% CI 1.37-8.38). It also stayed associated with a higher risk of the composite endpoint (HR 2.64, 95% CI 1.13-6.21).

How much weight to give it

The authors concluded that preclinical carotid atherosclerosis was independently associated with higher risk of events and death. They suggest carotid ultrasound may have a role as a complementary risk tool.

The cohort design supports association only. It cannot show that plaque causes events, or that scanning improves outcomes.

The sample is moderate in size and the number of events is small (45). The confidence intervals are wide, especially after adjustment, so the size of the risk is uncertain. The abstract reports adjusted results only for high plaque burden, not for any plaque.

The abstract does not report funding, how plaque was defined, which factors were adjusted for in detail, or whether plaque added predictive value beyond standard risk factors or risk scores. It also does not say whether scanning led to any change in care. The full paper should be checked for these points.

For your clinic

In this cohort of adults with T1D, carotid plaque, especially several plaques, was associated with a higher risk of cardiovascular events and death. The authors suggest that carotid ultrasound may have a potential role as a complementary tool for cardiovascular risk assessment in adults with T1D.

The study does not show that adding carotid ultrasound to routine care improves outcomes, and it does not say how a scan result should change management. Do not change practice on this study alone. Read the full paper, and check current guidelines on cardiovascular risk assessment in T1D, before using carotid ultrasound for this purpose.