Treatment responsiveness of phenotypes of symptomatic airways obstruction in adults.
BACKGROUND
Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous disorders encompassing different phenotypes of airflow obstruction, which might differ in their response to treatment.


OBJECTIVE
The aim of this study was to determine distinct phenotypes comprising the syndromes of asthma and COPD and the treatment responsiveness of these phenotypes to inhaled β-agonist, antimuscarinic, and corticosteroid therapy.


METHODS
We undertook a cross-sectional study with 3 phases. In phase 1, 1,264 participants aged 18 to 75 years with self-reported current wheeze and breathlessness were identified from a random population sample of 16,459. In phase 2, 451 participants attended for detailed assessment, including responsiveness to inhaled salbutamol and ipratropium bromide. In phase 3, 168 steroid-naive participants were enrolled in a 12-week trial of inhaled budesonide. Cluster analysis was performed in 389 participants who completed phase 2 with full data. Treatment responsiveness was compared between phenotypes.


RESULTS
Cluster analysis identified 5 phenotypes: moderate-to-severe childhood-onset atopic asthma, asthma-COPD overlap, obese-comorbid, mild childhood-onset atopic asthma, and mild intermittent. Bronchodilation after salbutamol was equal to or greater than that after ipratropium for all phenotypes. The moderate-to-severe childhood-onset atopic asthma, asthma-COPD overlap, and obese-comorbid phenotypes had greater efficacy with inhaled corticosteroid treatment than the mild intermittent group.


CONCLUSIONS
Cluster analysis of adults with symptomatic airflow obstruction identifies 5 disease phenotypes, including asthma-COPD overlap and obese-comorbid phenotypes, and provides evidence that patients with the asthma-COPD overlap syndrome might benefit from inhaled corticosteroid therapy.
Medical Research Institute of New Zealand, Wellington, New Zealand; Capital & Coast District Health Board, Wellington, New Zealand; Victoria University of Wellington, Wellington, New Zealand.
James
J
Fingleton
Medical Research Institute of New Zealand, Wellington, New Zealand; Hutt Valley District Health Board, Lower Hutt, New Zealand.
Justin
J
Travers
Medical Research Institute of New Zealand, Wellington, New Zealand.
Mathew
M
Williams
Medical Research Institute of New Zealand, Wellington, New Zealand.
Thomas
T
Charles
Medical Research Institute of New Zealand, Wellington, New Zealand; Capital & Coast District Health Board, Wellington, New Zealand.
Darren
D
Bowles
Medical Research Institute of New Zealand, Wellington, New Zealand.
Rianne
R
Strik
Medical Research Institute of New Zealand, Wellington, New Zealand; Capital & Coast District Health Board, Wellington, New Zealand.
Philippa
P
Shirtcliffe
Capital & Coast District Health Board, Wellington, New Zealand; University of Otago Wellington, Wellington, New Zealand.
Mark
M
Weatherall
Medical Research Institute of New Zealand, Wellington, New Zealand; Capital & Coast District Health Board, Wellington, New Zealand; Victoria University of Wellington, Wellington, New Zealand. Electronic address: richard.beasley@mrinz.ac.nz.
Richard
R
Beasley
D000293:Adolescent; D058666:Adrenergic beta-2 Receptor Agonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D000420:Albuterol / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D019819:Budesonide / Q000627:therapeutic use; D016000:Cluster Analysis; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D009241:Ipratropium / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000627:therapeutic use; D009765:Obesity / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D010641:Phenotype; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D058666:Adrenergic beta-2 Receptor Agonists; D018927:Anti-Asthmatic Agents; D005938:Glucocorticoids; D018727:Muscarinic Antagonists; D019819:Budesonide; D009241:Ipratropium; D000420:Albuterol
Phenotype; asthma; bronchodilator; chronic obstructive pulmonary disease; inhaled corticosteroid