Asthma characteristics in smoking patients with severe asthma
Published online January 31, 2025
Therapy with biologics is an established and effective treatment for patients with severe asthma. However, patients with more than 10 pack-years of smoking are frequently excluded from clinical trials, so little is known about this patient group.
A recent article by Biener et al., published in The Journal of Allergy and Clinical Immunology: In Practice analyzed data from 2,478 patients with severe asthma enrolled in the German Asthma Net (GAN). The study compared the characteristics of never-smokers and ever-smokers (active or former smoking history), who were further categorized into three groups based on cumulative tobacco exposure in pack-years (py). The authors examined differences in disease control, lung function parameters, biomarkers, medication use and co-morbidities - factors that are relevant, in determining eligibility for biologic therapy.
The sample included 56.8% never-smokers, 21.3% ever-smokers with less than 10 py, 12.3% with 10-20 py and 9.6% with more than 20 py. The mean age of all participants was 50.3 ± 17.1 years. At the time of examination, the majority of patients (60.2%) had inadequately controlled asthma; only 14.9% had well-controlled symptoms, while 24.1% had partially controlled asthma. Ever-smokers were older, more frequently male and had a higher body mass index. Regarding the primary outcome variables, patients with more than 20 py had poorer asthma control measured by the Asthma Control Test, and fractional exhaled nitric oxide (FeNO) levels were lower in ever-smokers. However, the other key parameters - including blood eosinophil count, serum IgE levels, forced expiratory volume in one second (FEV1), annual exacerbation rates, and long-term oral corticosteroid doses - were comparable across groups.
Smoking history was associated with a decrease in additional lung function parameters such as diffusion capacity and total lung volume. There were no major differences in medication use and comorbidities. Therefore, the authors concluded that patients with severe asthma and a smoking history beyond 10 pack-years may exhibit distinct features, but their core asthma characteristics are similar to those of never-smokers. This may be partly attributable to the precise characterization of asthma in the GAN registry.
In summary, the results underscore the importance of accurate asthma phenotyping and provide no justification for excluding patients from phenotype-tailored therapies such as biologics based solely on their smoking history. Nevertheless, smoking cessation remains a central focus of asthma treatment. Further studies are needed to better understand the impact of smoking history on the effectiveness of biologic therapies in asthma.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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