Respiratory medicine
Is COPD worse in people who also have asthma?
Open access · cc by · source: Europe PMC
Smokers with COPD who had asthma earlier in life had similar lung function to those with COPD alone but worse quality of life and far more frequent flare-ups.
Study at a glance
- Design
- Cross-sectional — Cross-sectional comparison within the multicentre COPDGene study of COPD patients (GOLD 2-4) with versus without physician-diagnosed asthma before age 40, adjusted for age, sex, race and pack-years.
- N
- N=915 · 915 COPD subjects with asthma history available (119 with asthma, rest COPD only), from the first 2500 COPDGene participants; a secondary analysis without the age limit included 1026.
- Population
- Non-Hispanic white and African American current or former smokers aged 45-80 with at least 10 pack-years and GOLD stage 2-4 COPD, from 21 US centres
- Outcome
- Respiratory exacerbations in the prior year, St George's Respiratory Questionnaire quality of life, BODE index, spirometry, six-minute walk and chest CT emphysema, gas trapping and airway wall measures
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Key findings
About 13% of the COPD group had early-onset asthma; they were younger, had smoked less and were more often African American. Despite similar lung function, walking distance and BODE scores, they had worse quality of life (about 5.2 points higher on the St George's questionnaire, a clinically meaningful difference), were nearly twice as likely to have had a severe exacerbation and more than three times as likely to be frequent exacerbators. On CT they showed more air trapping but no more emphysema, and African American race doubled the odds of having asthma alongside COPD.
Methodology
Using data from the first 2500 participants of COPDGene, a large US study of smokers, the researchers selected 915 people with moderate to very severe COPD. They compared the 119 who reported a doctor's diagnosis of asthma before age 40 with those who had COPD alone. Groups were compared on flare-ups (exacerbations) in the previous year, a respiratory quality-of-life questionnaire, lung function tests, a six-minute walk, and CT-scan measures of emphysema, air trapping and airway walls, with regression models adjusting for age, sex, race and smoking.
Limitations
Because the data are cross-sectional, the study cannot show how asthma and COPD interact over time or whether asthma causes the more severe course. Asthma was defined by self-report of a past doctor's diagnosis, which can be mistaken, and exacerbations were recalled for the prior year rather than tracked prospectively. Participants had not stopped their inhalers before spirometry, which may have hidden differences in bronchodilator response, and the sample was restricted to heavy smokers who were white or African American, so it may not generalise to other groups.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Earlier asthma marks a more flare-prone form of COPD.
Asthma history changes the course of COPD: among 915 COPDGene smokers with COPD, the 13% with asthma before age 40 had similar lung function but worse quality of life and were more than three times as likely to be frequent exacerbators.
Evidence for the claim as stated.
Earlier asthma marks a more flare-prone form of COPD.
Asthma history changes the course of COPD: among 915 COPDGene smokers with COPD, the 13% with asthma before age 40 had similar lung function but worse quality of life and were more than three times as likely to be frequent exacerbators.
Scope note — Cross-sectional, self-reported asthma diagnosis and recalled exacerbations.
Limits the claim's scope: a different population, assay, or outcome.
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