Estimation of cardiovascular risk (CVR) in individuals living with type 1 diabetes (T1D) was a key topic presented by Sophie Borot, MD, from Besançon University Hospital, Besançon, France, at the 40th congress of the French Society of Endocrinology. Borot highlighted the complexities of this subject, outlining several factors that contribute to its challenges.
A Heterogeneous Disease
T1D is a highly heterogeneous condition, and the patients included in studies reflect this diversity:
- The impact of blood glucose levels on CVR changes depending on diabetes duration, its history, the frequency of hypoglycemic episodes, average A1c levels over several years, and the patient’s age at diagnosis.
- A T1D diagnosis from the 1980s involved different management strategies compared with a diagnosis today.
- Patient profiles also vary based on complications such as nephropathy or cardiac autonomic neuropathy.
- Diffuse and distal arterial damage in T1D leads to more subtle and delayed pathologic events than in type 2 diabetes (T2D).
- Most clinical studies assess CVR over 10 years, but a 20- or 30-year evaluation would be more relevant.
- Patients may share CVR factors with the general population (eg, family history, smoking, sedentary lifestyle, obesity, hypertension, or elevated low-density lipoprotein [LDL] levels), raising questions about possible overlap with metabolic syndrome.
- Study criteria differ, with a focus on outcomes such as cardiovascular death, major adverse cardiovascular events like myocardial infarction and stroke, or other endpoints.
- CVR is measured using either absolute or relative values, with varying units of measurement.
A Recent Awareness
The concept of CVR in T1D is relatively new. Until the publication of the prospective Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study in 2005, it was believed that T1D control had no impact on CVR. However, follow-up results from the same cohort of 50,000 patients, published in 2022 after 30 years of observation, revealed that CVR was 20% higher in patients who received conventional hyperglycemia-targeted treatment than those undergoing intensive treatment. The CVR increases in conjunction with diabetes duration. The study also showed that even well-controlled glycemia in T1D carries CVR (primarily due to microangiopathy), and that the most critical factor for CVR is not A1c control but rather LDL cholesterol levels. 
These findings were corroborated by a Danish prospective study, which demonstrated that while CVR increased in conjunction with the number of risk factors, it was 82% higher in patients with T1D than in a control group — even in the absence of risk factors.
Key Takeaways
At diagnosis, a fundamental difference exists between T1D and T2D in terms of the urgency to address CVR. In T2D, diabetes may have progressed for years before diagnosis, necessitating immediate CVR reduction efforts. In contrast, T1D is often diagnosed in younger patients with initially low CVR, raising questions about the optimal timing for interventions such as statin prescriptions.
Recommendations
The American Diabetes Association/European Association for the Study of Diabetes guidelines (2024) include the following recommendations:
- For adults with T1D, treatment should mirror that for T2D:
- After age 40, statins should be prescribed systematically. Moderate-intensity statins are recommended for patients without CVR factors, targeting LDL < 0.7 g/L or a 50% reduction in LDL for those with at least one CVR factor.
- Between ages 20 and 40, statins are recommended if at least one CVR factor is present.
- For children 10 years of age or older with T1D, the LDL target is < 1.0 g/L. Statins are prescribed if LDL exceeds 1.6 g/L without CVR factors or 1.3 g/L with at least one CVR factor.
The European Society of Cardiology guidelines (2023) include the following:
- For the first time, a dedicated chapter addresses T1D. Like the American guidelines, routine statin use after age 40 is recommended.
- Before age 40, statins are prescribed if there is at least one CVR factor (microangiopathy) or a 10-year CVR ≥ 10% (based on a CVR calculator).
The International Society for Pediatric and Adolescent Diabetes guidelines (2022) recommend:
- For children 10 years of age or older, the LDL target is < 1.0 g/L. Statins are recommended if LDL exceeds 1.3 g/L.
CAC Score in High CVR
The French Society of Cardiology and the French-speaking Society of Diabetology recommend incorporating the coronary artery calcium (CAC) score to refine CVR classification in high-risk patients. For those without prior cardiovascular events, LDL targets vary based on CAC and age. For example:
- High-risk patients with a CAC of 0-10 are reclassified as moderate risk, with an LDL target of < 1 g/L.
- A CAC ≥ 400 indicates very high risk, warranting coronary exploration.
- Patients under 50 years of age with a CAC of 11-100 remain high risk, with an LDL target of 0.7 g/L.
Conclusion
CVR in patients with T1D remains challenging to define. However, it is essential to consider long-term outcomes, planning for 30 or 40 years into the future. This involves educating patients about the importance of prevention, even when reassuring numbers are seen in their youth.
This story was translated from Univadis France using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
