People with diabetes face a threefold to sixfold increased risk for sudden cardiac death and a shorter life expectancy than the general population, and this risk is especially noticeable among younger adults, a new study showed.

“We found that sudden cardiac death occurs more frequently in people with diabetes across all age groups, and that sudden cardiac death has a substantial impact on the shortened life expectancy seen in individuals with diabetes. That’s a new finding; and the magnitude of the contribution of sudden cardiac death to reduced life expectancy surprised us,” lead author Tobias Skjelbred, MD, of Copenhagen University Hospital in Copenhagen, Denmark, told Medscape Medical News. 

The study was published in the European Heart Journal on December 4.

The researchers analyzed data on all 54,028 deaths in Denmark during 2010. They examined death certificates, hospital discharge summaries, and autopsy reports to identify 6862 sudden cardiac deaths.

They then linked this information to patient records to establish which patients had diabetes.

Results showed sudden cardiac death was 3.7 times more common among people with type 1 diabetes and 6.5 times more common for people with type 2 diabetes than in the general population.

The incidence rate per 100,000 person-years of sudden cardiac death in individuals with type 1 diabetes and type 2 diabetes were 394 and 681, respectively. The incidence rate in the background population was 105.

The difference in risk was greatest in younger adults with diabetes, with people under 50 having a seven times higher risk for sudden cardiac death.

This probably reflects the low background risk for sudden cardiac death in younger people, making the relative impact of diabetes appear larger. In older age groups, the effect of diabetes is less pronounced due to the growing influence of other age-related risk factors for sudden cardiac death, the authors said.

The research also showed that the average life expectancy for individuals aged 30 years was 14.2 years shorter for those with type 1 diabetes and 7.9 years shorter for people with type 2 diabetes than the general population. And sudden cardiac death was responsible for 3.4 of the years lost in people with type 1 diabetes and 2.7 of the years lost in those with type 2 diabetes.

The increased risk for sudden cardiac death in diabetes persisted after adjustment for multiple confounders and across different age groups.

More than 500 million people are living with type 2 diabetes, and that number is expected to rise to about 780 million by 2045.

Complex Mechanisms

Researchers said the mechanisms underlying the link between diabetes and sudden cardiac death are complex, with the most common pathway related to underlying ischemic heart disease or other cardiovascular conditions.

But they noted that glycemic control has been proposed as a possible marker for risk stratification of sudden cardiac death in patients with diabetes.

Although glycemic control reduces the risk for cardiovascular events, it carries an increased risk for hypoglycemia, when glucose-lowering treatments include insulin and sulfonylureas. And acute hypoglycemia elicits sympathoadrenal activation, increases cardiac workload, and is associated with QT prolongation and hypokalemia. These potential arrhythmogenic factors might promote malignant arrhythmias leading to sudden cardiac death, the researchers said.

“These findings highlight the need to deepen our understanding of the diabetes-specific mechanisms that contribute to ventricular arrhythmias and sudden cardiac death,” they said.

Identify Highest-Risk Patients for ICDs

There would be a large potential gain in improving the prevention of ventricular arrhythmia in people with diabetes, according to the researchers.

As current prevention of sudden cardiac death relies on identification of high-risk patients who might benefit from an implantable cardioverter defibrillator (ICD), the researchers recommend further work to identify subsets of patients with diabetes in whom the benefits of an ICD may outweigh the possible risks and detrimental effects of such devices.

A key limitation of this study is that it focuses on deaths in 2010, which do not take into account the effect of newer cardioprotective diabetes treatments such as SGLT2 inhibitors and GLP-1 receptor agonists.

In an accompanying editorial, Yaxuan Gao, MD, and Hanno Tan, MD, of Amsterdam University Medical Center in Amsterdam, Netherlands, said this study highlights a crucial point — that patients with diabetes, particularly younger individuals, are at significantly elevated risk of sudden cardiac death.

While more data are needed to develop robust sudden cardiac arrest prediction models, the editorialists suggest it may be possible to reduce the burden of sudden cardiac death with personalized treatment interventions that aim to prevent sudden cardiac arrest.

“To achieve this, future research must delve deeper into the mechanisms underlying sudden cardiac arrest in diabetes, focusing on genetic susceptibility, cardiac ion channels, and the mechanisms of antidiabetic drugs. Understanding these interactions will inform more comprehensive prevention and treatment strategies for this population,” the editorialists concluded.

This work was supported by a research grant from the Danish Cardiovascular Academy, which is funded by the Novo Nordisk Foundation; and The Danish Heart Foundation. Skjelbred has received grants from the Danish Cardiovascular Academy. The editorialists reported having no disclosures.