LATE-BREAKING ABSTRACT: Predictors of lung function decline in a cohort of subjects with severe asthma

Abstract

Introduction: fix airflow obstruction has been observed in asthma, but little is known about its risk factors from longitudinal studies. Objectives: to describe trends of FEV 1 in patients with previously untreated severe asthma, following long term treatment; and to identify predictors of a steeper decline in FEV 1 . Methods: A cohort study of an average 8 years of follow up, with a minimum of three complete visits: the first, upon enrollment (V enroll ) in the severe asthma programme, the second after one year of regular treatment with a combination of inhaled corticosteroids (iCS) and long acting beta 2 agonist (V baseline ) and the final visit (V final ). Comparisons between V baseline and V final were performed in relation to FEV 1 post bronchodilator. Variables that could influence lung function decline were tested using logistic regression. Cluster analysis was used to characterize the groups according to their patterns of lung function decline. Results: 184 patients completed all visits. 36 of 184 (19,6%) had a decline in FEV 1post-BD ≥50ml/yr. Three patterns were found with different trends in lung function. The group with steeper decline in FEV 1 comprised non-atopics, having early onset asthma and better FEF 25-75% in V baseline . The predictors of steeper lung function decline are number of exacerbations, higher FEV 1 in the first year of treatment and higher doses of iCS. Conclusion: some patients with severe asthma present steeper FEV 1 decline, which is associated to early onset and non-atopic asthma. The predictors of accelerated decline in FEV 1 were number of exacerbation and higher doses of iCS. Neither better lung function at the V baseline , nor the use of higher doses of iCS were protective.