In a prospective population cohort study published in JAMA Cardiology, Aivaras Cepelis, MSc, of the Department of Public Health and Nursing, Faculty of Medicine and Health Science at the Norwegian University of Science and Technology in Trondheim, Norway, and colleagues found that asthma and a lack of asthma control were associated with a moderately increased risk for atrial fibrillation (AF) in a dose-response manner.
The lifetime risk for AF is 26%. As the population ages, there is a growing epidemic of AF, which increases the risk for stroke and cardiovascular mortality 2-fold. Evidence suggests that both uncontrolled asthma and AF are associated with high levels of systemic inflammation biomarkers. Moreover, short-acting and long-acting β2-agonists, which are the most commonly prescribed asthma medications, may affect heart rate and increase the risk for arrhythmias.
Investigators analyzed data from 54,567 adults; 5961 (10.9%) of whom reported ever having asthma, and 2485 of whom reported having active asthma (4.6%). During a mean 15.4-year follow-up, AF developed in 2071 (3.8%) participants. Individuals with clinician-diagnosed asthma were at an estimated 38% higher risk for AF (adjusted hazard ratio, 1.38) than those without asthma. Furthermore, the investigators noted a dose-response relationship between levels of asthma control and risk for AF (P for trend <.001). The highest risk for AF occurred in individuals with uncontrolled asthma (adjusted hazard ratio, 1.74; 95% CI, 1.25-2.41; P for trend <.001).
The study was limited by its observational nature, which carries the possibility of residual confounding. The investigators also noted that they did not have a full data set on heart failure, which is an important comorbidity of AF. In addition, sleep apnea can worsen asthma symptoms throughout the day and vice versa (eg, asthma can affect sleep apnea with nighttime awakenings and difficulty breathing), thus potentially confounding the results. Finally, the lack of a gold standard for asthma diagnosis may have resulted in misclassification of patients.
Nonetheless, the authors suggested that the high prevalence of asthma should give clinicians pause, and they should be aware of the possible connection between the 2 disorders. They also called for further investigation into the underlying mechanisms of the association.
Cepelis A, Brumpton BM, Malmo V, et al. Associations of asthma and asthma control with atrial fibrillation risk. Results from the Nord-Trøndelag Health Study (HUNT) [published online July 11, 2018]. JAMA Cardiol. doi:10.1001/jamacardio.2018.1901