Characterisation of patients with frequent exacerbation of asthma.

Background: Exacerbation is one of the most significant problems in patients with asthma. Although subpopulation of patients is more susceptible to exacerbations than others, which clinical features characterise susceptibility to exacerbation are not well understood.

Methods: Consecutive non-smoking adult patients with asthma who had multiple exacerbations (ME) despite regular maintenance treatment were compared with those who had at most single exacerbation as control during the previous 1 year. Exacerbation of asthma is defined initiations or escalations of systemic corticosteroid as part of the management for aggravated asthma condition.

Results: Patients with ME (n=32, male: 6, mean age: 46.7 years) were characterised by intensive current maintenance treatment (dose of inhaled corticosteroid; 1037.5+/-452.8 vs 621.6+/-257.3 microg, P=0.0005, proportion of oral corticosteroid users; 28.1% vs 2.7%, P=0.008), severe episodes of exacerbation (asthma-related hospitalisations; 71.9% vs 23.4%, P=0.0002, arrival on ambulance; 37.5% vs 8.1%, P=0.008), concomitant chronic sinusitis (34.4% vs 10.8%, P=0.038) and intolerance to non-steroidal anti-inflammatory drugs (NSAIDs) (34.4% vs 5.4%, P=0.006) in comparison with controls (n=37, male:11, mean age:44.4). Pulmonary function in patients with ME was characterised by persistent airflow limitation and reduced reversibility.

Conclusion: Patients with ME are at increased risk for severe exacerbation despite more intensive maintenance anti-inflammatory treatment. Persistent irreversible airflow limitation and complications of chronic sinusitis and/or NSAIDs intolerance are characteristics to this subpopulation.