People with persistent asthma have a higher carotid atherosclerotic plaque burden and higher levels of inflammatory biomarkers that put them at higher risk of major adverse cardiovascular events, a US study has shown.
The findings, published in the Journal of the American Heart Association, highlight the shared underlying inflammatory pathophysiology of asthma and cardiovascular disease, according to researchers at the University of Wisconsin in Madison.
“Many physicians and patients don’t realise that asthmatic airway inflammation may affect the arteries, so for people with persistent asthma, addressing risk factors for cardiovascular disease may be really helpful,” said lead study author Dr Matthew Tattersall of the university’s Division of Cardiovascular Medicine.
The researchers reviewed data from 5,029 healthy adults enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA) study, average age of 61, who had baseline risk factors for cardiovascular disease and for whom there was carotid ultrasound data.
A subgroup of 109 participants was identified with persistent asthma, defined as using daily controller medications to control asthma symptoms, in addition to 388 participants with intermittent asthma, defined as a history of asthma, but not using daily medications to control asthma symptoms.
At the start of the MESA study, all participants had an ultrasound of the left and right carotid arteries to identify any carotid artery plaque. The total plaque score defined the number of plaques in the walls of both carotid arteries. Blood levels of inflammatory biomarkers interleukin-6 (IL-6) and C-reactive protein (CRP) were also measured at the start of the MESA study.
Carotid plaque was present in 67% of participants with persistent asthma and 49.5% of those with intermittent asthma, and in 50.5% of the participants without asthma, who had an average of about one carotid plaque.
Those with persistent asthma had an average of two carotid plaques, and those with intermittent asthma about one carotid plaque.
After adjusting for factors such as age, sex, weight and smoking, participants with persistent asthma had nearly twice as high odds of having plaque in their carotid arteries than those without asthma (odds ratio, 1.83; p<.001)
When compared to participants without asthma, those with persistent asthma had higher levels of inflammatory biomarkers. (Individuals with persistent asthma had an average IL-6 level of 1.89 pg/mL, while those free from asthma had an average IL-6 level of 1.52 pg/mL.)
The association between persistent asthma and increased carotid artery plaque risk and burden remained after adjusting for inflammatory marker levels.
“This analysis tells us that the increased risk for carotid plaques among people with persistent asthma is probably affected by multiple factors,” said Dr Tattersall said.
“Participants who have persistent asthma had elevated levels of inflammation in their blood, even though their asthma was treated with medication, which highlights the inflammatory features of asthma. We know that higher levels of inflammation lead to negative effects on the cardiovascular system.”
Dr Tattershall noted that American Heart Association guidelines for primary prevention of cardiovascular disease include inflammatory disorders such as arthritis and lupus as cardiovascular risk-enhancing factors. He suggested that persistent asthma may also be included in future guidance.
“The most important message from our findings is that more significant forms of asthma are associated with more cardiovascular disease and cardiovascular events,” he said.
“Persistent asthma is an inflammatory syndrome that is associated with increased atherosclerotic cardiovascular disease risk, highlighting the importance of optimising control of atherosclerotic cardiovascular disease risk factors in patients with persistent asthma,” the authors concluded.