Aspirin sensitivity and severity of asthma: evidence for irreversible airway obstruction in patients with severe or difficult-to-treat asthma.

BACKGROUND: Patients with aspirin sensitivity experience hyperplastic sinusitis and nasal polyposis. We speculated that similar mechanisms could be acting in the lower airway and that these individuals would demonstrate more severe asthma and irreversible loss of lung function.
OBJECTIVE: We sought to investigate the role of aspirin-exacerbated respiratory disease (AERD) as a risk factor for the development of irreversible airway obstruction.
METHODS: The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study is a multicenter observational study of subjects with severe or difficult-to-treat asthma. Data were compared between subjects who reported asthma exacerbation after aspirin ingestion and those who did not. The primary measure of bronchodilator-resistant obstruction (possible remodeling) was the maximally achieved postbronchodilator spirometry averaged over the 3-year duration of the study.
RESULTS: Adult subjects (>/=18 years) with AERD (n = 459) were compared with subjects with non-aspirin-sensitive asthma (n = 2848). Subjects with AERD had significantly lower mean postbronchodilator percent predicted FEV(1) compared with subjects with non-aspirin-sensitive asthma (75.3% vs 79.9%, P < .001). Differences in spirometry between the 2 cohorts persisted after controlling for potential confounding variables. In addition, subjects with AERD were more likely to have severe asthma by means of physician assessment (66% vs 49%, P < .001), to have been intubated (20% vs 11%, P < .001), to have a steroid burst in the previous 3 months (56% vs 46%, P < .001), and to have required high-dose inhaled corticosteroids (34% vs 26%, P < .001).
CONCLUSIONS: These data suggest that aspirin sensitivity is associated with increased asthma severity and possible remodeling of both the upper and lower airways.