Diabetes Tied to Increased Risk of Sudden Cardiac Death

Adults with type 1 diabetes (T1D) and type 2 diabetes (T2D) face substantially higher rates of sudden cardiac death (SCD) across all age groups, especially younger adults, according to findings from a Danish nationwide analysis.¹

Published in the European Heart Journal, these findings underscore SCD as a major contributor to reduced life expectancy among adults with diabetes and highlight the need for better cardiovascular risk stratification and prevention strategies. Investigators reviewed all 54,028 deaths that occurred in Denmark in 2010 and used death certificates, hospital summaries, and autopsy reports to identify 6862 cases of SCD. They then linked these records to national registries to determine diabetes status and quantify incidence rates (IR).

“This is an observational study, meaning that we can see a link between diabetes and sudden cardiac death, but we cannot prove that one causes the other,” Tobias Skjelbred, MD, lead study author and cardiologist at Copenhagen University Hospital, said in a news release.² “Sudden cardiac death is challenging to predict and prevent, but these findings reinforce the importance for people with diabetes to work with their clinicians to reduce cardiovascular risk.”

Risk Varies by Age, Diabetes Type

Compared with the general population, SCD was 3.7 times more common in adults with T1D (95% CI, 3.4-4.1) and 6.5 times more common with T2D (95% CI, 6.0-7.0).¹ The rate of SCD occurrence increased with age, and the IR ratio grew more similar between patients with and without diabetes as they got older, especially after age 80, when other age-related risk factors come into play.

The gap in risk was especially pronounced in younger adults with T1D—patients aged 30 to 40 years were 22.7 times more likely to experience SCD than the general population if they had T1D, but only 1.8 times more likely if they had T2D. Patients aged 40 to 50 had similarly increased risks: 6.3 times higher with T1D and 6 times higher with T2D. According to the authors, the higher IR ratio in younger adults likely reflects the low background rate of SCD in this age range.

“While sudden cardiac death risk increases with age for everyone, the relative difference is most pronounced when comparing younger people with diabetes to their peers in the general population,” Skjelbred said.²

Reduced Life Expectancy

The study also demonstrated notable reductions in life expectancy.¹ A 30-year-old patient with T1D had an average life expectancy 14.2 years shorter than the general population, 3.4 of which were attributable to SCD, according to the authors. For patients with T2D, their life expectancy was 7.9 years shorter, with 2.7 years lost specifically due to SCD.

Researchers pointed to several diabetes-specific mechanisms that may increase arrhythmogenic vulnerability, including ischemic heart disease, autonomic neuropathy, and hypoglycemia. Among SCD cases with diabetes, 37% of individuals with T1D and 7.2% with T2D had a documented history of severe hypoglycemia, suggesting metabolic instability may contribute to fatal ventricular arrhythmias.

“Our findings suggest that there is a large potential gain in improving prevention of ventricular arrhythmia in individuals with diabetes,” the study authors said. “The age at which SCD occurs is an important consideration, and we show that this group has a significantly shortened life span compared with the background population.”

As diabetes prevalence rises globally, identifying high-risk subgroups and better understanding the mechanisms of SCD will be increasingly important for prevention, risk stratification, and care coordination.³

“A key limitation of this study is that it focuses on deaths in 2010, before widespread use of newer glucose-lowering therapies such as SGLT2 inhibitors and GLP-1 receptor agonists,” Skjelbred noted.² “We therefore cannot assess how these treatments may have influenced sudden cardiac death in more recent years.”

References

1. Skjelbred T, Warming PE, Behr ER, et al. Diabetes and sudden cardiac death: a Danish nationwide study. Eur Heart J. Published online December 3, 2025. doi:10.1093/eurheartj/ehaf826
2. People with diabetes face higher risk of sudden cardiac death. News release. European Society of Cardiology. December 3, 2025. Accessed December 3, 2025. https://www.eurekalert.org/news-releases/1107954
3. Klein HE. Diabetes prevalence expected to double globally by 2050. AJMC^®. June 22, 2023. December 3, 2025. https://www.ajmc.com/view/diabetes-prevalence-expected-to-double-globally-by-2050