Severe and active eczema increase risks for cardiac disease

Adults with severe and active eczema are at increased risk for non-lethal heart disease outcomes, according to a new study published in The BMJ.

“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,” stated lead investigator, Sinéad M. Langan, PhD, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London. “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.”

Emerging research findings indicate that the systemic inflammatory aspect of eczema could play a role in heart disease outcomes. Findings from specific cohort studies performed in the United States, Denmark, and Taiwan, however, have been mixed, with a lack of clarity as to whether either inflammation secondary to atopic eczema or increased cardiac risk factors are responsible for this relationship. Researchers also wonder whether eczema severity and activity could play a role in heart disease.

In this study, researchers examined whether adults with atopic eczema are at increased risk for cardiovascular disease, and whether this risk varies according to disease severity and activity over time.

In this population-based matched cohort study, the researchers mined electronic health record data from primary-care practices in the UK—with linked data reflecting hospital stays and cause-specific mortality. Using a validated algorithm, they identified atopic eczema in the sample. The algorithm demonstrated a comparable distribution of severity of atopic eczema with extant studies in the literature. Moreover, the researchers had access to information about body mass index, smoking, and severe alcohol use, which allowed for adjustment for potentially causal covariates.

Dr. Langan and colleagues matched 387,439 adult patients with atopic eczema to 1,528,477 adult patients without atopic eczema (median age: 43 years; 66% women). They followed subjects for a median duration of 5.1 years.

The team figured hazard ratios for the association between atopic eczema and each of the following outcomes: myocardial infarction, unstable angina, heart failure, atrial fibrillation, stroke, and cardiovascular death.

Subjects with severe eczema included those taking oral immunosuppressive drugs for eczema, those administered phototherapy treatment for eczema, and those presenting to dermatologists for the condition.

The investigators found that patients with severe atopic eczema displayed the following:

• 20% increased risk of stroke (HR: 1.22; 99% CI: 1.01-1.48);
• 40%-50% increased risk of myocardial infarction, unstable angina, atrial fibrillation, and cardiovascular death;
• 70% increased risk of heart failure (HR: 1.69; 99% CI: 1.38-2.06).

These associations held for severe atopic eczema following sensitivity analysis for potential confounders; they also held for the most active eczema group.

Counterintuitively, the authors found that compared with no eczema, low atopic eczema activity protected against death.

“This finding may be explained by the poor capture of data on activity: some patients may have active atopic eczema but do not adhere to treatment, thus being misclassified as never active,” they wrote. Dr. Langan and colleagues suggest possible limitations of their study. For instance, it was hard to tease the effects of long-term eczema therapy from severity due to the observational nature of this research. Additionally, they point to the possibility of further confounding, bias, and missing data.

Nevertheless, their findings are clinically relevant.

“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,” concluded Dr. Langan.

This research was funded by a Wellcome senior research fellowship in clinical science.