Heart Attack Deaths Static in Those With Type 1 Diabetes

Miriam E. Tucker

September 13, 2023

People with type 1 diabetes have not experienced the same improved survival after a heart attack over the past 15 years that has occurred in people with type 2 diabetes and those without diabetes, new research shows.

Between 2006 and 2020, the annual incidences of overall mortality and major adverse cardiovascular events after a first-time myocardial infarction dropped significantly for people with type 2 diabetes and those without diabetes (controls).

However, the same trend was not seen for people with type 1 diabetes.

"There is an urgent need for further studies understanding cardiovascular disease in people with type 1 diabetes. Clinicians have to be aware of the absence of the declined mortality trend in people with type 1 diabetes having a first-time myocardial infarction," lead author Thomas Nyström, MD, professor of medicine at the Karolinska Institute, Stockholm, Sweden, told Medscape Medical News.

The findings are scheduled to be presented October 5, 2023, at the annual meeting of the European Association for the Study of Diabetes (EASD).

Discussing potential reasons for the findings, the authors say that the standard care after a heart attack has improved with more availability of, for example, percutaneous coronary intervention and better overall medical treatment. However, this standard of care should have improved in all three groups.

"Although glycemic control and diabetes duration were much different between diabetes groups, in that those with type 1 had been exposed for a longer period of glycemia, the current study cannot tell whether glucose control is behind the association between mortality trends observed. Whether this is the case must be investigated with further studies," Nyström said.

Data From Swedish Healthcare Registry

Among people with a first-time MI recorded in national Swedish healthcare registries between 2006 and 2020, there were 2527 individuals with type 1 diabetes, 48,321 with type 2 diabetes, and 243,170 controls with neither form of diabetes.

Those with type 1 diabetes were younger than those with type 2 diabetes and controls (62 years vs 75 and 73 years, respectively). The type 1 diabetes group also had a higher proportion of females (43.6% vs 38.1% of both the type 2 diabetes and control groups).

The proportions of people with the most severe type of heart attack, ST-elevation MI (STEMI), vs non-STEMI were 29% vs 71% in the type 1 diabetes group, 30% vs 70% in the type 2 diabetes group, and 39% vs 61% in the control group, respectively.

After adjustment for covariates including age, sex, comorbidities, socioeconomic factors, and medication, there was a significant decreased annual incidence trend for all-cause death among the controls (-1.9%) and persons with type 2 diabetes (-1.3%), but there was no such decrease among those with type 1 diabetes.

For cardiovascular deaths, the annual incidence declines were -2.0% and -1.6% in the control group and the type 2 diabetes group, respectively, vs a nonsignificant -0.5% decline in the type 1 diabetes group. Similarly, for major adverse cardiovascular events, those decreases were -2.0% for controls and -1.6% for those with type 2 diabetes, but -0.6% for those with type 1 diabetes — again, a nonsignificant value.

"During the last 15 years, the risk of death and major cardiovascular events in people without diabetes and with type 2 diabetes after having a first-time heart attack has decreased significantly. In contrast, this decreasing trend was absent in people with type 1 diabetes. Our study highlights the urgent need for understanding the cardiovascular risk in people with type 1 diabetes," the authors conclude.

Nyström has received honoraria from AstraZeneca, Merck Sharp & Dohme, Novo Nordisk, Eli Lilly and Company, Boehringer Ingelheim, Abbott, and Amgen. The authors acknowledge the ALF agreement between Stockholm County Council and Karolinska Institutet.

To be presented October 5, 2023, at the European Association for the Study of Diabetes Annual Meeting; October 2-6, 2023; Hamburg, Germany.

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape, with other work appearing in the Washington Post, NPR's Shots blog, and Diabetes Forecast magazine. She is on Twitter @MiriamETucker.

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