COPENHAGEN – Adults with atopic dermatitis are at significantly increased risk of acute MI compared with the general population, according to a Danish national population-based case-control study.
Indeed, Danish adults with atopic dermatitis (AD) were at a 1.67-fold increased risk for an MI in a Cox regression analysis adjusted for age, gender, education level, and cardiovascular risk factors, Dr. Jette Lindorff Riis reported at the annual congress of the European Academy of Dermatology and Venereology.
“The associated MI risk is comparable to that of Danish patients with psoriasis, another inflammatory skin disease, which has been associated with increased cardiovascular risk,” said Dr. Riis of Aarhus (Denmark) University Hospital.
Her study included all 5,278 Danish adult AD patients who met the study enrollment criteria: born in 1900-1983, received a hospital discharge diagnosis of AD during 1977-2012, and had at least one additional hospital inpatient or outpatient visit for AD during follow-up. Three-quarters of patients were born in 1960-1983, the rest earlier. The follow-up period began at the time of hospital diagnosis of AD and continued to the time of MI, death, or the end of 2012.
The requirement that participants had to be diagnosed as having AD by a hospital-based physician, in most cases a dermatologist, and that they had to have a second hospital encounter for AD was created to minimize the likelihood of misdiagnosis, a not uncommon occurrence in the primary care setting, she explained.
Each of the 5,278 adults with AD was matched based upon age and gender with 10 controls. Follow-up was accomplished through linkages between Denmark’s comprehensive cradle-to-grave population-wide registries.
During a maximum follow-up of 35 years, the AD patients were at a 1.67-fold greater risk than that of controls after adjustment for potential confounders, including standard cardiovascular risk factors, stroke, and the use of antihypertensive, lipid-lowering, and antidiabetic medications.
The Danish registry data do not contain specific information about patients’ AD disease severity, so as a crude proxy the investigators looked at the number of hospital inpatient or outpatient visits for AD. They found that patients with 2-4 visits had an adjusted 1.31-fold increased risk of acute MI compared with controls, those with 5-9 visits had a 1.83-fold increased risk, and those with 10 or more hospital encounters for AD during follow-up had a 2.42-fold increased risk.
When Dr. Riis and coinvestigators compared adult Danes with AD to a Danish national cohort of psoriasis patients, they found the AD patients were at an adjusted 15% increased risk of MI, a nonsignificant difference. That’s an important finding, since a link between psoriasis and increased cardiovascular risk was first reported nearly a decade ago and has since been confirmed in multiple studies. Given that AD is quite common among adults – various studies have reported prevalence rates of 2%-10% – and that the skin disease appears to boost the risk of what is already the No. 1 cause of mortality in developed countries, the new findings have major implications for clinical practice.
“We might have to think more about cardiovascular risk factor reduction on a daily basis in order to take good care of our atopic dermatitis patients,” Dr. Riis observed.
The Danish study is the latest in a very recent flurry of research pointing for the first time to increased cardiovascular risk in adult AD. Earlier this year investigators at Northwestern University, Chicago, reported finding that adult atopic dermatitis patients have increased levels of cardiovascular risk factors (J Allergy Clin Immunol. 2015 Mar;135:721-8.e6), and even more recently they reported increased rates of coronary artery disease and MI in adults with self-reported AD in analyses of the National Health and Nutrition Examination Survey and the 2010 and 2012 Health Interview Survey (Allergy. 2015 Oct;70:1300-8).
Moreover, earlier this year, Dr. Riis’ colleagues at Aarhus reported a significantly increased rate of asymptomatic coronary artery stenosis in AD patients compared with controls (Am J Med. 2015 Jun 18. pii: S0002-934300545-8).
Dr. Riis said she’s eager to see studies evaluating whether systemic treatments for AD, which dampen systemic inflammation, also curb the elevated acute MI risk.
Audience comments centered around the issue of whether the Danish results apply to the many less-severe cases of adult AD that never necessitate a trip to the hospital. Are those patients also at increased risk of MI? Dr. Riis said that remains an unanswered question, given that the investigators couldn’t find a reliable indicator of disease severity in the databases. They tried using systemic therapy as a proxy, but it turned out too few AD patients used systemic agents to be able to draw conclusions, which suggests the study population wasn’t at the extreme end of the AD severity spectrum.