"Link found between severe eczema and heart problems," reports The Guardian.
A large UK study found that people with severe eczema were more likely than people without eczema to develop a range of heart conditions, including unstable angina, heart attack and heart failure.
The researchers were looking at the most common type of eczema, atopic eczema, which causes skin to become itchy, red, dry and cracked.
The study used NHS records for 387,439 adults with eczema and a matched sample of 1,528,477 people without the condition. Over an average follow-up period of 5 years, researchers found that people with eczema were more likely to have unstable angina (where people have unpredictable symptoms and not just when being physically active), heart failure, heart arrhythmia or stroke.
However, this difference was mainly driven by results from the 5% of people in the study with severe forms of eczema. For people with mild eczema, there was little, if any, increase in risk of heart problems.
We also cannot tell what's behind the risk. It could be because long-term inflammation caused by the disease damages the heart and blood vessels, while another possibility is that long-term use of severe-eczema medications might increase the risk of heart problems.
The researchers said GPs should be aware of the potential risk so patients with eczema can be advised about ways to protect against heart problems. These include keeping active, cutting down on salt and saturated fats, and not smoking. Read more advice about heart health.
Where did the story come from?
The researchers were from the London School of Hygiene and Tropical Medicine, and Royal Sussex County Hospital in the UK; the University of California in the US; and Aarhus University in Denmark. The study was funded by the Wellcome Foundation and published in the British Medical Journal, and is free to read online.
The Guardian story was balanced and accurate, making clear that we do not know the reasons for the link between eczema and heart problems.
What kind of research was this?
This was a matched cohort study, where people with eczema were matched with similar people without the condition and then followed up to see what happened in terms of their cardiovascular health.
This type of study is good for spotting links between factors (such as eczema and cardiovascular disease), but it cannot show that one factor directly causes another.
What did the research involve?
The researchers used a large UK primary care database, the Clinical Practice Research Datalink, to identify anonymised information about adults diagnosed with eczema.
They then identified up to 5 people of the same sex, in a similar age group and in the same geographical area, and checked whether they received a cardiovascular disease diagnosis during an average follow-up period of 5.1 years. The researchers also used data from the Office for National Statistics, and NHS Hospital Episode Statistics, which record people's interactions with secondary care.
After accounting for potential confounding factors, they estimated the risk of having a cardiovascular disease for people with eczema in comparison with those who did not have the condition, focusing on:
- heart attack
- unstable angina
- heart failure
- atrial fibrillation
- death from cardiovascular disease
- heart bypass operations
Severe eczema was defined as eczema where a person had been prescribed immunosuppressant tablets, phototherapy (where UV light is used to reduce inflammation) or having been referred to secondary care for eczema treatment.
In addition to disease severity, researchers took account of the following in the main analysis:
- period people were in the study
- time since diagnosis
- deprivation levels
- body mass index
- high cholesterol
- high blood pressure
- depression or anxiety
- excessive alcohol intake
The main analysis did not account for medicine use, but the researchers did a separate analysis adjusting figures for use of high-dose oral corticosteroid tablets. Long-term use of these can increase blood pressure, weight and blood sugar, raising the chance of heart problems.
What were the basic results?
The main analysis found that people with eczema had a 7% to 17% increased chance of unstable angina, heart failure, atrial fibrillation and stroke.
When taking account of high-dose oral corticosteroid use, the risks for the same conditions held true but were slightly lower.
However, the risks were greater when looking at results for people with severe eczema. In comparison with people without eczema, they had a:
- 37% increased chance of heart attack (hazard ratio [HR] 1.37, 95% confidence interval [CI] 1.12 to 1.68)
- 41% increased chance of unstable angina (HR 1.41, 95% CI 1.02 to 1.95)
- 67% increased chance of heart failure (HR 1.67, 95% CI 1.36 to 2.05)
- 35% increased chance of atrial fibrillation (HR 1.35, 95% CI 1.14 to 1.59)
- 30% increased chance of cardiovascular death (HR 1.30, 95% CI 1.10 to 1.53)
- 36% increased chance of heart bypass (HR 1.36, 95% CI 1.10 to 1.69)
How did the researchers interpret the results?
The researchers said the results showed "a clinically relevant increase in the risk of cardiovascular outcomes in patients with atopic eczema" but that the increased risk "is largely confined to patients with severe or more active" forms of the condition.
They added that doctors should consider "developing prevention strategies to reduce the risk of cardiovascular disease among patients with severe or predominantly active atopic eczema".
Headlines about an increased risk of heart problems if you have eczema might be worrying, but these results only apply to the small minority of people with very severe eczema – not to people with mild eczema.
The results may help doctors better target cardiovascular disease prevention strategies at people with severe eczema to reduce future risk. The results also add to our growing understanding of how diseases that cause inflammation in the body may also contribute to cardiovascular disease risk.
The study was large and well conducted, but it did have 3 significant limitations:
- it cannot distinguish between the effects of the disease and the effects of treatments, as people with more severe eczema receive stronger treatments
- almost 20% of the original study group had to be excluded because of missing data (mainly BMI values)
- classifying disease severity by the treatments people were given may have meant missing anyone who had severe eczema but had declined treatment
As is the case for everyone, the risk of cardiovascular disease for people with eczema can be reduced by eating a healthy diet, taking exercise, maintaining a healthy weight, not smoking and not drinking too much alcohol.
Find out more about how to reduce the chances of cardiovascular disease.