Lung Function Trajectory Types in Never-Smoking Adults With Asthma: Clinical Features and Inflammatory Patterns.
10.4168/aair.2018.10.6.614
- Author:
Joo Hee KIM
1
;
Hun Soo CHANG
;
Seung Woo SHIN
;
Dong Gyu BAEK
;
Ji Hye SON
;
Choon Sik PARK
;
Jong Sook PARK
Author Information
1. Division of Pulmonology, Allergy and Critical Care, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.
- Publication Type:Original Article
- Keywords:
Adult;
asthma;
disease progression;
forced expiratory volume;
inflammation;
phenotype
- MeSH:
Adult*;
Airway Obstruction;
Asthma*;
Disease Progression;
Eosinophils;
Forced Expiratory Volume;
Humans;
Immunoglobulin E;
Immunoglobulins;
Inflammation;
Longitudinal Studies;
Lung*;
Methods;
Neutrophils;
Phenotype;
Sputum;
Steroids
- From:Allergy, Asthma & Immunology Research
2018;10(6):614-627
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: Asthma is a heterogeneous disease that responds to medications to varying degrees. Cluster analyses have identified several phenotypes and variables related to fixed airway obstruction; however, few longitudinal studies of lung function have been performed on adult asthmatics. We investigated clinical, demographic, and inflammatory factors related to persistent airflow limitation based on lung function trajectories over 1 year. METHODS: Serial post-bronchodilator forced expiratory volume (FEV) 1% values were obtained from 1,679 asthmatics who were followed up every 3 months for 1 year. First, a hierarchical cluster analysis was performed using Ward's method to generate a dendrogram for the optimum number of clusters using the complete post-FEV1 sets from 448 subjects. Then, a trajectory cluster analysis of serial post-FEV1 sets was performed using the k-means clustering for the longitudinal data trajectory method. Next, trajectory clustering for the serial post-FEV1 sets of a total of 1,679 asthmatics was performed after imputation of missing post-FEV1 values using regression methods. RESULTS: Trajectories 1 and 2 were associated with normal lung function during the study period, and trajectory 3 was associated with a reversal to normal of the moderately decreased baseline FEV1 within 3 months. Trajectories 4 and 5 were associated with severe asthma with a marked reduction in baseline FEV1. However, the FEV1 associated with trajectory 4 was increased at 3 months, whereas the FEV1 associated with trajectory 5 was persistently disturbed over 1 year. Compared with trajectory 4, trajectory 5 was associated with older asthmatics with less atopy, a lower immunoglobulin E (IgE) level, sputum neutrophilia and higher dosages of oral steroids. In contrast, trajectory 4 was associated with higher sputum and blood eosinophil counts and more frequent exacerbations. CONCLUSIONS: Trajectory clustering analysis of FEV1 identified 5 distinct types, representing well-preserved to severely decreased FEV1. Persistent airflow obstruction may be related to non-atopy, a low IgE level, and older age accompanied by neutrophilic inflammation and low baseline FEV1 levels.
