Greater CVD Focus Urged for T1D

MADRID — Emerging data pointed to the urgent need for cardiovascular risk reduction in all adults with type 1 diabetes (T1D), including those who are young and those diagnosed in adulthood.

At the European Association for the Study of Diabetes (EASD) 2024 Annual Meeting, two entire oral abstract sessions were devoted to research examining cardiovascular risk specifically in people with T1D. There is increasing evidence that as with type 2 diabetes (T2D), clinical visits need to focus on other cardiovascular risk factors and glucose.

Findings included the evidence of severe coronary artery disease (CAD) in asymptomatic adults with T1D, increased risks for mortality and cardiac events in people diagnosed with T1D in adulthood, and a greater cardiovascular risk for those with overweight/obesity and among those with more cumulative exposure to both hyperglycemia and dyslipidemia.

One speaker, Dr Rebecka Johanna Bergdal, of the Folkhälsan Research Center and the University of Helsinki, Helsinki, Finland, issued a “call to action,” saying, “We call on healthcare professionals to continue supporting and encouraging individuals with T1D towards better management of diabetes, including both glucose and lipid management.”

Session Moderator Krzysztof Strojek, MD, PhD, head of the Department of Internal Medicine, Diabetology and Cardiometabolic Diseases at the Medical University of Silesia, Katowice, Poland, told Medscape Medical News that all the data point in the same direction for T1D management, to “look not only at A1c and blood glucose control but also lipids, hypertension, smoking status, all these risk factors recognized in type 2…are also important in T1D.”

The ‘Alarming’ Finding of CAD in Asymptomatic Patients

Michal Dubsky, of the Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic, presented findings from 62 asymptomatic patients with T1D for > 10 years (mean, 36 years), with a mean A1c of 7.5% (58 mmol/mol), and no prior history of cardiovascular disease (CVD). They had slightly elevated CVD biomarkers, including a mean low-density lipoprotein (LDL) cholesterol level of 2.33 mmol/L, lipoprotein (a) level of 15 nmol/L, and N-terminal pro-B-type natriuretic peptide level of 125.3 ng/L. 

All underwent a noninvasive carotid ultrasound and coronary artery calcium (CAC) scoring. Of those, 12 patients had a CAC score > 400 and/or presence of two or more carotid plaques identified as high-risk.

Those 12 patients underwent coronary angiography and had a total of 29 vessels examined by optical coherence tomography (OCT), “an invasive intravascular method for assessing coronary atherosclerosis that is far more sensitive than standard coronary angiography, especially for the detection of high-risk vulnerable plaques without a hemodynamically significant stenosis,” Dubsky explained.

Coronary angiography showed obstructive CAD in 5 of the 12 patients. Their mean calcium score was 950 and mean number of carotid plaques was 2.8. Features associated with plaque vulnerability included microphage accumulation in 24 vessels, lipid-rich plaques in 23, spotty calcium in 19, and neovascularizations in 13.

Thin-cap fibroatheroma, a strong predictor of plaque rupture, was present in 7 of the 12 patients (58.3%), and four had features of very high-risk plaques, defined as thin-cap fibroatheroma with a minimal lumen area < 3.5 mm², a lipid arch > 180 degrees, and macrophages. 

“Our study showed that asymptomatic T1D patients with high CAC score and carotid plaques had very severe OCT findings. We observed a significant proportion of high-risk lesions potentially associated with plaque rupture and risk of CV death. Therefore, we believe these patients should be treated as very high-risk with target LDL below 1.4 mmol/L (55 mg/dL), even though they are completely asymptomatic,” Dubsky concluded.

He added that because OCT is invasive and costly, the CAC score can be used to guide the decision for statin use, with any score above 100 considered elevated risk. 

Study Co-author Martin Haluzik, MD, professor of internal medicine in the Charles University, Prague, Czech Republic, told Medscape Medical News, “I think it’s very alarming because some of these are basically very healthy-looking young people, so you don’t really expect them to have significant cardiovascular complications already or significant plaques. I think it shows that we should be more proactive in looking into the risk of cardiovascular complications and in looking into the early cardiovascular changes.”

Later Diagnosis Doesn’t Always Protect: Risk Seen in Adult-Onset T1D

Yuxia Wei, a PhD student at the Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, presented an analysis of data from Sweden’s national health databases comparing cardiovascular outcomes between 10,184 people diagnosed with T1D at ages 18-29 years, 30-39 years, and ≥ 40 years; another 375,523 people diagnosed with T2D at those ages; and 509,172 population controls matched for age, sex, and county.

Those diagnosed after age 40 years had higher A1c levels and were less likely to be using insulin pumps than those diagnosed at younger adult ages. 

Compared with population controls, at a median of about 7 years of follow-up, people with T1D had significantly higher all-cause mortality at all diagnosis age groups, with a hazard ratio of 1.71. This rose to 2.78 for those diagnosed at age 30-39 years.

Compared with those with T2D, the mortality risks weren’t significantly different at any age, but the risks for non-cardiovascular death, including from cancer and infection, were significantly higher among those diagnosed after age 40 years (1.31 overall). Those diagnosed with T1D at any adult age had lower risks for major cardiovascular events than those diagnosed with T2D. Hazard ratios ranged from 0.27 for those diagnosed at age 18-29 years to 0.78 for those diagnosed after the age of 40 years.

Smoking and A1c above target were the greatest contributors to mortality. Those two factors, along with body mass index (BMI), were the strongest contributors to major adverse cardiovascular events (MACE). 

“Adult-onset T1D carries excess risk of death and cardiovascular disease, without obvious attenuation over age at diagnosis…Smoking, A1c, and BMI are the key factors to be managed to improve prognosis in adult-onset T1D,” Wei concluded. 

BMI: Often Overlooked in T1D, but a Major CVD Risk Factor

Two studies examined the link between overweight/obesity and cardiovascular risk in T1D. One, by Dr Laurence Salle, of the Endocrinology, Diabetes and Metabolic Diseases Department at CHU Limoges, Limoges, France, was a prospective, longitudinal cohort study of 2367 people with T1D at 68 centers in France who didn’t have a cardiovascular history at baseline. 

Of those, 51% had normal BMI (18.5-24.9), 31% had overweight (25-29.9), and 18% had obesity (≥ 30). Cardiovascular risk factors, including LDL cholesterol, triglycerides, and hypertension increased with an increasing BMI. The 10-year CVD risk was significantly higher for those with overweight (9.61%) and obesity (9.93%) than for those with normal weight (7.24%), in both men and women. 

However, BMI was found to be an independent predictor of 10-year high cardiovascular risk in men but not women, while waist:height ratio independently predicted risk in both men and women, Salle reported.

The second BMI study, from Enrique Soto-Pedre, MBBS, of the Division of Population Health and Genomics at the University of Dundee, Dundee, Scotland, presented data on a retrospective follow-up from 1995 to 2019 of 1973 people with T1D aged > 18 years at diagnosis (42% women; mean age, 34.2 years; 18.9% had obesity. 

After 10 years of follow-up, those with overweight and obesity had significantly higher odds of developing arterial hypertension, even among those taking angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, with statistically significant adjusted hazard ratios of 1.73 and 3.37 for the obese and overweight groups, respectively. 

MACE were significantly more common among those with obesity, with an adjusted hazard ratio of 2.95, as was acute myocardial infarction, 3.33. 

“These results emphasize the importance of incorporating weight management into the overall management of individuals with T1D. No one has doubts about weight management in T2D, but in type 1, it’s not so clear. One of the main [concerns] would be safety [in terms of hypoglycemia],” Soto-Pedre concluded. 

Call for Action: Cumulative Glucose and Lipid Exposures Increase Risk

Bergdal presented data on the effects of cumulative glycemia and lipids on the risk for CAD in 3495 adults with T1D who had been diagnosed prior to the age of 40 years. The history of CAD or stroke was exclusion criteria. There were a total of 534 CAD events within a median follow-up of 19.4 years.

Cumulative glycemia, LDL cholesterol, triglycerides, and non–high-density lipoprotein cholesterol exposures were all significantly associated with CAD risk (P < .001 for all). With an adjustment for confounders, the highest tertile of glycemia was associated with a twofold increased risk for CAD. Both hyperglycemia and dyslipidemia were independently associated with CAD risk, Bergdal reported. 

“It’s important to minimize the time spent above A1c 7%, and lipid management in T1D must not be forgotten,” she said, prior to issuing her call for action.

Haluzik reported receiving honoraria for talks and/or consultancy and/or research funding from Eli Lilly, Novo Nordisk, Sanofi, AstraZeneca, Mundipharma, Bristol Myers Squibb, Amgen, Boehringer Ingelheim, Janssen, Ypsomed, and Johnson & Johnson. The presenters had no disclosures. 

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X: @MiriamETucker.