Late Asthma Boosts Cardiovascular Risks

The risk of cardiovascular disease (CVD) events is increased in patients who have late-onset asthma, according to a new study.

After more than a decade of observation, the rate of CVD events was 1.6‐fold higher in patients with late‐onset asthma-but not in those with early‐onset asthma-than in nonasthmatics after adjustment for age, sex, and CVD risk factors, stated the researchers, led by Matthew C. Tattersall, DO, MS, of the University of Wisconsin-Madison.

They followed participants from the Wisconsin Sleep Cohort who were free of CVD at baseline for a mean of 14 years for development of CVD (myocardial infarction, angina, stroke, coronary revascularization, heart failure, or CVD death). Late‐onset asthma was defined as physician‐diagnosed asthma beginning at age 18 years or older.

The study included 1269 participants, mean age 47.3 years. Of 166 patients with asthma, 111 had late‐onset and 55 had early‐onset. Those who had late‐onset asthma were more likely to be female and to have a higher body mass index (BMI) than those who did not have asthma. The mean age of asthma diagnosis in the late‐onset group was 39.5 years versus 8.9 years in the early‐onset group.

There was no interaction between BMI and age of asthma diagnosis on incident CVD, they stated.

Previous studies that investigated the associations of asthma and CVD showed mixed results, some finding no significant association with CVD, others finding limited associations with specific end points, and still others finding consistent associations with CVD, the researchers noted.

“The heterogeneity of associations between asthma and CVD observed in the prior reports may be due, in part, to the treatment of asthma as a homogeneous condition, when in fact asthma is a heterogeneous condition with unique pathophysiology that describes specific subtypes,” they stated.

Two previous studies looked specifically at the age of asthma onset and CVD risk. The Atherosclerosis Risk in Communities (ARIC) study found that only women with adult-onset asthma have a higher risk of coronary heart disease or stroke. An analysis of 1999–2006 NHANES data found an increased risk of CVD with adult-onset asthma.

Both studies found a significant effect modification by sex in the association of late‐onset asthma and CVD. Tattersall and colleagues did not find a significant effect modification by sex, but they noted that their study was smaller and may not have adequate power to detect effect modification.

“Despite the study size, we saw a similar magnitude of association in fully adjusted models, further strengthening the support for the association of late‐onset asthma and CVD,” they stated.

Early‐onset and late‐onset asthma are substantially different disease processes, even though they are often lumped together, the researchers noted. They differ in risk factors, pathophysiology, and responses to treatment. Early‐onset asthma generally is responsive to treatment with inhaled corticosteroids. Late‐onset asthma often is more severe and refractory to standard treatments.

“Given the public health burden of asthma, further investigations into the mechanisms of this association in specific asthma phenotypes are needed,” they concluded.

The researchers published their results online August 24, 2016 in the Journal of the American Heart Association.