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. 2021 Sep 16:14:1105-1115.
doi: 10.2147/JAA.S327659. eCollection 2021.

Severe Asthma in a General Population Study: Prevalence and Clinical Characteristics

Lina Rönnebjerg  1 , Malin Axelsson  2 , Hannu Kankaanranta  1   3   4 , Helena Backman  5 , Madeleine Rådinger  1 , Bo Lundbäck  1 , Linda Ekerljung  1
Affiliations

Severe Asthma in a General Population Study: Prevalence and Clinical Characteristics

Lina Rönnebjerg et al. J Asthma Allergy. .

Abstract

Purpose: Current guidelines primarily use medication levels to distinguish severe asthma from other types of asthma. In addition, severe asthma must also be uncontrolled at high-intensity treatment or become uncontrolled if treatment level is decreased. To date, only a few studies have used this definition to investigate the prevalence and clinical characteristics of severe asthma in population-based samples. Therefore, the aim of this study was to evaluate the prevalence and clinical characteristics of individuals with severe asthma in the population-representative West Sweden Asthma Study.

Materials and methods: In this cross-sectional population-based study, a randomly selected sample (n=1172) and a separate asthma sample (n=744) underwent clinical examinations, completed a structured interview and responded to questionnaires. Severe asthma was defined as at least one feature of uncontrolled asthma despite treatment in line with the Global Initiative for Asthma (GINA) steps 4/5. This treatment level required a minimum medium dose of inhaled corticosteroids (ICS) plus a second controller or oral corticosteroids.

Results: The prevalence of severe asthma was 1.1% in the adult random sample and 9.5% within the asthma sample. Individuals with severe asthma were older and had more symptoms, activity limitations, heart disease and blood neutrophils compared to those with other asthma. They also had lower lung function and despite these impairments, 32% did not have annual contact with a healthcare provider.

Conclusion: The prevalence of severe asthma was higher compared to previous studies, and many individuals with severe asthma did not have regular contact with healthcare providers. Due to the high burden of symptoms and impairments for individuals with severe asthma, it is important that the healthcare system implement strategies to improve follow-up and evaluate these patients according to existing guidelines.

Keywords: asthma control; asthma epidemiology; asthma severity symptoms; asthma-medication; lung function.

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Conflict of interest statement

Ms Lina Rönnebjerg reports personal fees from AstraZeneca, outside the submitted work. Professor Hannu Kankaanranta reports personal fees, non-financial support from AstraZeneca, Orion Pharma; personal fees from Boehringer-Ingelheim, Chiesi Pharma, GlaxoSmithKline, MSD, Mundipharma, Novartis, and Sanofi, outside the submitted work. Dr Helena Backman reports personal fees from Astra Zeneca and Boehringer Ingelheim, outside the submitted work. Professor Bo Lundbäck reports grants from ThermoFisher, personal fees from Sanofi, outside the submitted work. The authors report no other conflicts of interest in this work.

Figures

Figure 1
Figure 1
Flowchart with sampling procedure of the study population and prevalence of severe, other and no asthma in the random sample (A) and prevalence of severe and other asthma in the asthma sample (B). Image of Europe and West Sweden made by Anders Euren, University of Gothenburg.
Figure 2
Figure 2
Lung function measurements among individuals with severe vs other asthma in proportions (A) and medians and median ratios (B). Spirometry available in: n=735 (69 severe and 666 other asthma) and 714 for reversibility test (66 severe and 648 other asthma). #FVC was the only continuous variable that was normally distributed in both of the groups. Mean FVC for severe and other asthma was 91.3 (SD 17.8) and 101.6 (SD 13.0), respectively. The p-value from the two-tailed independent samples t-test however, was not deviating from the Mann–Whitney U-test. For consistency, we present median with IQR and statistical significance from the Mann–Whitney U-test for FVC also.
Figure 3
Figure 3
Impact on daily life. Prevalence of symptoms and events within the last 12 months among persons with severe vs other asthma. ACT, Asthma Control Test; only available in n=432 (46 severe and 386 other asthma). Responses from remaining variables were available in 84–100% of asthma sample (n=744).
See this image and copyright information in PMC

References

    1. Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014;43(2):343–373. doi:10.1183/09031936.00202013 - DOI - PubMed
    1. Global Initiative for Asthma. Global strategy for asthma management and prevention. Available from:www.ginasthma.org/gina-reports/. Accessed October13 2020.
    1. Shaw DE, Sousa AR, Fowler SJ, et al. Clinical and inflammatory characteristics of the European U-BIOPRED adult severe asthma cohort. Eur Respir J. 2015;46(5):1308–1321. doi:10.1183/13993003.00779-2015 - DOI - PubMed
    1. Aubier M, Thabut G, Fabry-Vendrand C. Characteristics of patients with severe, uncontrolled, eosinophilic asthma enrolled in a French cohort. J Asthma Allergy. 2018;11:217–224. doi:10.2147/JAA.S170866 - DOI - PMC - PubMed
    1. Backman H, Jansson SA, Stridsman C, et al. Severe asthma-A population study perspective. Clin Exp Allergy. 2019;49(6):819–828. doi:10.1111/cea.13378 - DOI - PubMed

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