Poor symptom control correlates with frequent exacerbations in severe asthma
Published online: July 1, 2021
Severe asthma patients are particularly prone to frequent exacerbations. Risk factors for frequent exacerbations include asthma comorbidities, smoking history and biomarkers of type 2 inflammation. These factors were identified in clinical trial cohorts or mixed asthma populations and therefore may not be applicable to a more general severe asthma population. Better understanding and management of factors associated with frequent exacerbations in patients with severe asthma would significantly reduce the health and socioeconomic burden of their condition.
In a UK Severe Asthma Registry (UKSAR) study published in The Journal of Allergy and Clinical Immunology: In Practice, Yang et al. investigated factors associated with frequent exacerbations in adult severe asthma patients in the UK. The UKSAR includes well-characterized severe asthma patients with good adherence and treated co-morbidities. Twenty-eight potential risk factors were assessed for associations with frequent exacerbations and then adjusted for factors with positive associations to identify independent factors related to frequent exacerbations. Furthermore, the authors investigated differences in risk factor profiles in those with and without maintenance oral corticosteroids (OCS) because type 2 inflammation is suppressed in the presence of OCS.
Several factors were associated with frequent exacerbations in 1,592 severe asthma patients, of whom 52% were on maintenance OCS. Asthma control questionnaire (ACQ-6) score greater than 1.5, past smoking history, blood eosinophilia, and high exhaled nitric oxide (FeNO) above 50ppb were associated with increased exacerbations. However, ACQ-6 demonstrated the strongest relationship with frequent exacerbations after adjustment for other factors. In those not on maintenance OCS, markers of type 2 inflammation such as blood eosinophilia and high FeNO were related to frequent exacerbations, but this was not independent of other factors. In those on maintenance OCS, previous smoking history was associated with frequent exacerbations. In both groups, ACQ-6 was the only common factor independently associated with frequent exacerbations. These findings lead the authors to conclude that poor symptom control has the strongest association with frequent exacerbations in patients with severe asthma, good adherence, and treated comorbidities. In addition, the relationship between biomarkers of type 2 inflammation and frequent exacerbations is less apparent in patients on maintenance OCS. This study proposed ACQ-6 as a useful clinical tool for identifying severe asthma patients who are at high risk of exacerbations. Prompt and effective treatment of this high-risk cohort would lead to significant improvements in both individual and organizational outcomes.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.