Fixed airways obstruction among patients with severe asthma: findings from the Singapore General Hospital-Severe Asthma Phenotype Study.

Autor: Yii AC, Tan GL, Tan KL, Lapperre TS, Koh MS; Department of Respiratory and Critical Care Medicine, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore. mariko.koh.s.y@sgh.com.sg.
Jazyk: angličtina
Zdroj: BMC pulmonary medicine [BMC Pulm Med] 2014 Dec 03; Vol. 14, pp. 191. Date of Electronic Publication: 2014 Dec 03.
DOI: 10.1186/1471-2466-14-191
Abstrakt: Background: A subset of severe asthma patients has fixed airways obstruction, which is characterized by incomplete reversibility to bronchodilator challenge. We aimed to elucidate the factors associated with fixed airways obstruction in a cohort of patients with severe asthma in Singapore.
Methods: 245 patients from the Singapore General Hospital-Severe Asthma Phenotype Study (SGH-SAPS) were screened. These patients fulfilled World Health Organization criteria for "treatment-resistant severe asthma" and were all on combination of high-dose inhaled corticosteroids and long-acting beta2 agonists. 76 patients had pre- and postbronchodilator lung function tests and were selected for analysis. They were divided into two groups based on postbronchodilator (Post BD) forced expiratory volume in one second, PostBDFEV1 % predicted: ≥70% (Non-Fixed Obs) and < 70% (Fixed Obs). We compared clinical and demographic parameters between the two groups.
Results: Patients in the Fixed Obs group were more frequently past or current smokers and had a higher pack-year smoking history. Overall, pack-year smoking history had a modest negative correlation with PostBDFEV1 % predicted. Atopy, allergen sensitization (type and numbers), comorbidities, symptoms, health care utilization and medication use did not differ between the two groups. The prebronchodilator FEV1 % predicted, FEV1/FVC and FVC % predicted were significantly lower in the Fixed Obs group. In addition, prebronchodilator FVC % predicted accounted for more variability than FEV1/FVC in predicting PostBDFEV1% predicted.
Conclusion: Smoking is associated with fixed airways obstruction in patients with treatment-resistant severe asthma in Singapore. Furthermore, our results suggest that both small and large airways obstruction contribute independently to fixed airways obstruction in severe asthma.
Databáze: MEDLINE
Externí odkaz: