A new research study, published in JAMA Cardiology, aimed to further confirm a previous correlation between asthma and atrial fibrillation (AF) and to determine if the degree of asthma control affected the risk of developing AF.
Atrial fibrillation (AF) is a known risk factor for increasing cardiovascular mortality and stroke. Now a new research study aims to further confirm a previous correlation between asthma and AF and also to determine if the degree of asthma control affected the risk of developing AF.
Population data for this study was gathered from 2 health studies, HUNT 2 and HUNT 3, and split into patients with and without asthma. Patients with asthma were further categorized into 3 groups based on a questionnaire:
To determine if the severity of asthma control impacted the risk of AF, patients with asthma were also subcategorized into “well controlled,” “partly controlled,” and “poorly controlled” according to daytime symptoms, limitation of activity, nighttime awakenings, and use of asthma reliever medications. AF assessment was determined through an echocardiogram or written records reviewed by specialists in cardiology and internal medicine.
After a mean follow-up time of 15.4 years, patients categorized in the ever asthma group had an estimated 30% higher risk of developing AF than those without asthma (hazard ratio [HR], 1.30; 95% CI, 1.13-1.48). Patients in the diagnosed asthma and active asthma groups had an estimated 42% (HR, 1.42; 95% CI, 1.21-1.67) and 81% (HR, 1.81; 95% CI, 1.51-2.16) increased risk, respectively.
There was also a significant association between asthma control and the risk of AF (P< .001 for trend). In patients with controlled asthma, there was an estimated 19% increased risk of AF (HR, 1.19; 95% CI, 0.98-1.45). The risks were higher when asthma control was inadequate, with an estimated 42% increased risk in partly controlled patients (HR, 1.42; 95% CI, 1.16-1.73) and an estimated 74% increased risk in uncontrolled asthma patients (HR, 1.74; 95% CI,1.25-2.41). A sensitivity analysis that excluded the data of participants who only had a 5-year follow-up period and those with comorbid conditions (myocardial infarction, heart failure, diagnosed with asthma after age 40) also showed an association of asthma with AF.
One interesting finding was that neither β2-agonists use nor high sensitivity C-reactive protein (hsCRP) had significant heart rate changes or increased risk of AF. High dose β2-agonists used for asthma has shown increased risk of arrhythmias and electrolyte disturbances, 2 major factors of AF. In this study, however, β2-agonists did not seem to increase risks of AF. Higher levels of hsCRP also did not contribute to increased risks of AF. This finding was not as surprising because inflammation has never been proven to contribute to developing AF.
These study results are essential in not only associating asthma to an increased risk of developing AF, but also identifying that poor asthma control contributes to AF more than well-controlled asthma. By recognizing the association between asthma and AF, clinicians can observe their asthma patients more closely for signs of AF and to treat them more appropriately.
Cepelis A, Brumpton BM, Malmo V, et al. Associations of asthma and asthma control with atrial fibrillation risk [published online July 11, 2018]. JAMA Cardiol. doi:10.1001/jamacardio.2018.1901.