SELECTED ARTICLES FROM THE RECENT LITERATURE 2004

10/15/04

Parameters associated with persistent airflow obstruction in severe asthma

Summary
Background - The mechanisms underlying persistent obstruction in severe asthma are not well defined with evidence for both bronchial inflammation and structural changes in the airways.

Findings - Bumbacea et al of the University de Medecina Carol Davila in Bucharest, Romania compared 2 groups of severe asthmatics defined by the characteristics of their post-bronchodilator FEV-1 (PBF). Group 1 had PBF <50% predicted; Group 2 had PBF >80% of predicted. They found that Group 1 patients were older and had longer duration of asthma. Exhaled nitric oxide levels and blood eosinophil counts were higher in the Group 1 patients. There was also greater bronchial wall thickening and dilatation in Group 1 with no greater air trapping than in Group 2. In individual patients, the degree of irreversible airflow obstruction correlated significantly with blood eosinophil levels and the degree of bronchial wall thickening.

However, there was no significant differences between Groups 1 and 2 in smoking history, atopic status, frequency of in-patient admissions for asthma flares, quality of life scores and the amount of oral and inhaled corticosteroids used.

Conclusions - Severe post bronchodilator airway obstruction is associated with greater inflammatory responses and evidence of airway remodeling even though there was no apparent difference in quality of life and corticosteroid treatment when compared to that in patients without such post bronchodilator obstruction.

Reference
Eur Respir J 2004;24:122-8

Editor's Comments
The expiratory airflow obstruction in asthma has traditionally been considered to be “reversible” with use of inhaled beta agonists (and sometimes only with inhaled corticosteroids). However, it is now recognized that a minority of asthmatics, particularly those with more severe disease, do not exhibit prominent reversibility of the airflow obstruction with inhaled beta agonists. Such “irreversible” obstruction appears to be progressive over time as witnessed in this study with increase frequency in older patients with asthma of longer duration. Both inflammatory and structural changes appear to play pathogenic roles. Yet, the quality of life does not appear to be significantly worse in those with such irreversible obstruction.

 

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