Abstract
It is uncertain whether phenotypes of asthma and chronic obstructive pulmonary disease (COPD) vary between populations with different genetic and environmental characteristics. Here, our objective was to compare the phenotypes of airways disease in two separate populations.
This was a cross-sectional observational study in adult populations from New Zealand and China. Participants aged 40–75 years who reported wheeze and breathlessness in the last 12 months were randomly selected from the general population and underwent detailed characterisation. Complete data for cluster analysis were available for 345 participants. Hierarchical cluster analysis was undertaken, based on 12 variables: forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity ratio, bronchodilator reversibility, peak expiratory flow variability, transfer coefficient of the lung for carbon monoxide, exhaled nitric oxide fraction, total IgE, C-reactive protein, age of symptom onset, body mass index, health status and cigarette smoke exposure.
Cluster analysis of the combined dataset described five phenotypes: “severe late-onset asthma/COPD overlap group”, “moderately severe early-onset asthma/COPD overlap group”, “moderate to severe asthma group with type 2 predominant disease”, and two groups with minimal airflow obstruction, differentiated by age of onset. Separate analyses by country showed similar patterns; however, a distinct obese/comorbid group was observed in the New Zealand population.
Cluster analysis of adults with symptomatic airways disease suggests the presence of similar asthma/COPD overlap phenotypes within populations with different genetic and environmental characteristics, and an obese/comorbid phenotype in a Western population.
Abstract
Evidence of asthma/COPD overlap phenotypes in China and NZ populations and obese/comorbid group in NZ http://ow.ly/APWk30eVBm5
Footnotes
This article has supplementary material available from erj.ersjournals.com
The NZRHS is registered with the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) with identifier number ACTRN12610000666022
Support statement: Primary funder: AstraZeneca AB, Sweden. Secondary funding: Health Research Council of New Zealand (reference 10/174), a Government funding organisation; the Medical Research Institute of New Zealand receives funding from the Health Research Council of New Zealand through the Independent Research Organisations Capability Fund (14/1002); the Research Special Fund for Capital Health Development (Shou-Fa 2011-1004-01); Project in the National Science and Technology Pillar Program during the Twelfth Five-Year Plan Period (2012BAI05B02, 2014BAI08B04, 2013BAI09B10). This was an investigator-sponsored and -designed study. The primary funder had the opportunity to review and comment on the study protocol prior to initiation of the study. Funding information for this article has been deposited with the Crossref Funder Registry.
Conflict of interest: Disclosures can be found alongside this article at erj.ersjournals.com
- Received May 9, 2017.
- Accepted August 29, 2017.
- Copyright ©ERS 2017
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