People with diabetes face higher risk of sudden cardiac death

The risk of sudden cardiac death is higher both for people with type 1 and type 2 diabetes, according to a large study published in the European Heart Journal [1] today (Thursday). The increase in risk is especially noticeable among younger adults.

Sudden cardiac death is when someone dies suddenly and unexpectedly due to a problem with their heart. It is generally rare in young and seemingly healthy individuals.

The research also shows that people with diabetes have a shorter life expectancy on average, and that a proportion of this reduction is due to sudden cardiac death.

The research was led by Dr Tobias Skjelbred from Copenhagen University Hospital, Rigshospitalet, Denmark, and included data on the entire Danish population in 2010.

The researchers looked at all 54,028 deaths in the country over that year and used death certificates, hospital discharge summaries and autopsy reports to identify all sudden cardiac deaths. They found 6,862 cases.

By combining this with records of which people had type 1 diabetes, type 2 diabetes or neither, the researchers were able to compare rates of sudden cardiac death between the three groups.

They found that 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, compared with the general population. The difference in risk was greatest in younger adults, with people under 50 who have diabetes having a seven times higher risk of sudden cardiac death.

The research also showed that the average life expectancy was 14.2 years shorter for people with type 1 diabetes and 7.9 years shorter for people with type 2 diabetes. Sudden cardiac death was responsible for 3.4 of the years lost in people with type 1 diabetes and 2.7 in people with type 2 diabetes.

Dr Skjelbred said: “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 in individuals with diabetes. 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.

“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. 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.

“There are probably several reasons behind this link, and these may differ by age. Having diabetes predisposes people to ischaemic heart disease, which is a key mechanism. In addition, diabetes-specific factors such as hypoglycaemia and cardiac autonomic neuropathy may increase the chances of an irregular heartbeat and sudden cardiac death.

“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. We therefore cannot assess how these treatments may have influenced sudden cardiac death in more recent years.”

People who are known to have a very high risk of sudden cardiac death can be fitted with an implantable cardioverter-defibrillator, so researchers say the next step could be to identify subgroups within the diabetes population who might benefit from preventive strategies, and to study how to lower the risk for people with diabetes.

In an accompanying editorial [2], Dr Hanno Tan from Amsterdam UMC, University of Amsterdam, Netherlands and colleague said: “Despite significant advances in cardiovascular medicine, sudden cardiac death (SCD) remains a challenge for prevention and treatment due to its unpredictable nature and high fatality rate.

“Previous studies have indicated that the incidence of sudden cardiac arrest (SCA) in diabetics is elevated compared to the general population.

“In this issue of the European Heart Journal, Skjelbred et al expand upon these previous studies, furthering our understanding of the relationship between diabetes and SCD. For the first time, the extent of both loss in life expectancy due to diabetes and the contribution of SCD to this loss is quantified.

“Of particular interest is the finding that the diabetes-associated risk of SCD was higher among younger individuals than among older individuals. For example, the incidence rate was highest in the 30-40 year age group among type 1 diabetes patients (22.7), and in the 40-50 year age group among type 2 diabetes patients (6.0).

“[…] studies have been initiated to develop systems that may autonomously detect SCA and call the emergency number, e.g., through the use of wearables such as smartwatches. Such solutions may have particular relevance for type 1 diabetes patients, because the proportion of unwitnessed SCA events is higher in these patients than in the general population. Thus, type 1 diabetes patients may derive particular benefit from these solutions.

“[…] we may be able to reduce the burden of SCD in diabetes patients with the use of personalised treatment interventions that aim at preventing SCA and/or improving SCA treatment.”