Led by the London School of Hygiene & Tropical Medicine, the study examined the health records of almost 2m people in the UK. Patients with severe eczema were found to experience a 20% increased risk of stroke (389/19,622 patients with severe eczema v 21,387/1,528,477 without), 70% increased risk of heart failure (419/19,624 v 16,983/1,528,477), and 40-50% increased risk of the remaining cardiovascular outcomes, including unstable angina, myocardial infarction, atrial fibrillation and cardiovascular death, compared to patients without eczema.
Patients with eczema of any kind were 10-20% more likely to experience non-fatal cardiovascular disease than patients without eczema, but the absolute risk is low (for example, over a one year period 25 in every 10,000 patients with eczema will have heart failure, compared to 21 in every 10,000 people without eczema).
Eczema can vary over time and patients whose eczema was active for most of their follow up were also at greater risk of cardiovascular outcomes. The risk was mainly confined to patients with severe eczema, including people on oral immunosuppressive drugs, those receiving phototherapy treatment for eczema or who were referred to dermatologists.
Although this observational study can't show cause and effect, cardiovascular prevention strategies among patients with severe and predominantly active eczema should be considered if findings are replicated by future studies.
Eczema, also known as atopic eczema or atopic dermatitis, is a common systemic inflammatory skin condition which affects up to 10% of adults in the UK and is becoming more common globally. Of those with eczema, 30% have moderate to severe disease with approximately 5% having severe disease. Symptoms include intense itch, pain and sleeplessness.
Dr Sinead Langan, Wellcome Trust Senior Fellow at the London School of Hygiene & Tropical Medicine and study lead investigator, said: "Eczema is a debilitating common condition. Increasing evidence suggests that severe eczema could be associated with a wider range of health problems than originally thought. Previous studies on the link between eczema and cardiovascular disease have reported mixed findings. However, these have lacked data on specific risk factors and have not assessed levels of eczema activity over time, points which our research addressed."
Using UK electronic health records from the Clinical Practice Research Datalink, Hospital Episode Statistics and data from the Office for National Statistics between 1998 and 2015, the researchers matched patients diagnosed with eczema and those without eczema on age, gender, general practice and calendar time. After adjusting for confounders such as socioeconomic status and age, the researchers examined the differences in cardiovascular disease risk between the two groups. Risks in severe eczema persisted after taking into account known cardiovascular risk factors, such as weight (BMI), smoking and alcohol intake.
Dr Langan said: "We found that severe eczema was linked with an increased risk of not only stroke and heart failure, but also a 30-40% increased risk of unstable angina, myocardial infarction, atrial fibrillation and cardiovascular death. Patients experiencing very severe eczema and those with symptoms the majority of the time were most at risk.
"It's important to highlight the absolute risk of people with eczema experiencing a cardiovascular event is low. However, with heart and circulatory disease causing more than a quarter of all deaths in the UK, it's important we explore all potential risk factors.
The links uncovered in our research, if robustly replicated by future studies, would support targeted screening and focus on primary prevention strategies to reduce cardiovascular disease among patients with eczema."
The authors acknowledge limitations of their study, including misclassification of eczema disease severity, though this is likely to have led to underestimation of the true associations. It is also not possible to completely disentangle the effects of eczema therapy and disease severity.