Patients aged 50 and older with recent active asthma are at elevated risk of abdominal aortic aneurysm and aneurysm rupture, according to new research.
A common inflammatory pathway between asthma and AAA, first observed nearly a decade ago in mice, is thought to be responsible.
The new findings, published online Feb. 11 in Arteriosclerosis, Thrombosis, and Vascular Biology (Arterioscler Thromb Vasc Biol. 2016. doi: 10.1161/ATVBAHA.115.306497) support the association in humans.
©Dr. Cong-Lin Liu
This is a fragment of a ruptured human abdominal aortic aneurysm.
In a news release accompanying the findings, lead study author Guo-Ping Shi, D.Sc., of Brigham and Women’s Hospital and Harvard Medical School, Boston, said that the findings had clear clinical implications for older patients with a recent asthma diagnosis. Such patients, particularly older men, “should be checked for signs” of abdominal aortic aneurysm, Dr. Shi said.
For their research, Dr. Shi, along with colleagues at Zhengzhou (China) University, used data from a large Danish population-based cohort of nearly 16,000 patients (81% men) with AAA between 1996 and 2012, of which about 4,500 patients had rupture. They also looked at data from a comparison cohort of patients with and without AAA from a slightly larger population-based vascular screening trial of men in Denmark.
The investigators showed that hospital diagnosis of asthma within the previous year (n = 514) was associated with significantly higher risk of hospital admission with AAA rupture (n = 146) both before and after adjustment for AAA comorbidities (adjusted odds ratio 1.51-2.06). Higher risk of rupture also was seen for patients filling prescriptions for bronchodilators within the previous 3 months (aOR = 1.10-1.31), and for patients prescribed anti-asthma drugs (aOR OR = 1.09-1.48), which were seen as indicative of an outpatient asthma diagnosis.
“A hospital diagnosis of asthma or a recently filled prescription of an anti-asthmatic drug is associated with an increased risk of admission with rAAA compared with admission with intact AAA, both before and after adjusting for AAA comorbidities and relevant medications,” the researchers wrote in their analysis.
Moreover, “an asthma diagnosis or the use of bronchodilators or other anti-asthmatic drug prescriptions closer to the date of admission with AAA correlated directly with a higher risk of aortic rupture. The results remained robust after adjusting for a wide range of relevant possible confounders,” the researchers wrote.
In the cohort of patients from the vascular screening study, which included age-matched controls without AAA, asthma (measured by recent anti-asthmatic medication use) was seen associated with a significantly elevated risk of AAA before (OR = 1.45) and after adjustment for smoking (OR = 1.45) or other risk factors (OR = 1.46). This does not refer to rupture but just AAA.
Dr. Shi and colleagues noted that the AAA cohort lacked sufficient information on cigarette smoking, a known risk factor for AAA and AAA rupture, to preclude the possibility of confounding; however, the second all-male cohort did have extensive data on smoking, “and the risk of AAA among patients with asthma remained 45% higher than that of patients with nonasthma” even after adjustment.
The researchers hypothesized that an inflammatory response characterized by elevated immunoglobulin E may be the link between AAA pathogenesis and asthma, and that other allergic inflammatory diseases, including atopic dermatitis, allergic rhinitis, and some ocular allergic diseases, could potentially carry risks for AAA formation and rupture. Dr. Shi and colleagues previously investigated the IgE and aneurysm link in animal studies.
“The results have implications for the development of much needed advances in the prevention, screening criteria, and treatment of AAA, common conditions for which we currently lack sufficiently effective approaches,” the investigators wrote.
The Chinese, Danish, and U.S. governments sponsored the study. The investigators disclosed no conflicts of interest.