Increased Blood Eosinophil Counts, IgE Levels Linked to Higher Exacerbation Rates in Severe Asthma

November 17, 2020
Sydney Jennings
Sydney Jennings

Increased blood eosinophil counts and IgE levels are associated with higher exacerbation rates in patients with severe asthma, according to new research presented at ACAAI 2020.

New research presented at the virtual American College of Allergy, Asthma & Immunology Annual Scientific Meeting, showed a “substantial burden” of asthma exacerbations across increased blood eosinophil counts (BEC) and total immunoglobulin E (IgE) levels in patients with severe asthma not receiving biologics or systemic corticosteroids (SCS).

Research has shown an association between asthma exacerbation frequency and increased BEC; however, few studies have analyzed the real-world, contemporary frequency of asthma exacerbations by total IgE levels in patients with severe asthma.

Using data from patients enrolled in the CHRONICLE study, researchers examined the association between biomarkers (highest BEC and highest total IgE) and annualized rates of asthma exacerbations, emergency department (ED) visits, and hospitalizations while patients were not receiving biologics or SCS.

CHRONICLE is an ongoing observational study of US adults aged ≥18 years with severe asthma treated by allergists/immunologists or pulmonologist at participating sites. Asthma exacerbation was defined in this study as an exacerbation requiring inpatient hospitalization or treatment with ≥3 days of oral corticosteroids or ≥1 corticosteroid injection.

Of the 1884 patients enrolled in CHRONICLE between February 2018 and February 2020, 1196 did not receive biologics or SCS. Of these patients, 584 had BEC and 266 had total IgE levels reported.

Also, results showed that higher BEC (≥300 cells/μL) and total IgE were associated with higher rates of asthma exacerbations, ED visits, and hospitalizations, a finding the study authors note in their conclusion that is consistent with previous research.

“Total IgE <30, for which there is no labeled dosage of the anti-IgE biologic omalizumab, was associated with higher exacerbation risk,” concluded authors. “The higher exacerbation rates with lower total IgE levels may be due to increased disease severity among non-allergic patients, particularly among this population of patients not treated by biologics.”