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

• Main Authors: Rönnebjerg L, Axelsson M, Kankaanranta H, Backman H, Rådinger M, Lundbäck B, Ekerljung L
• Format: Article
• Language: English
• Published: Dove Medical Press 2021-09-01
• Series: Journal of Asthma and Allergy
• Subjects: asthma epidemiology; asthma control; asthma-medication; asthma severity symptoms; lung function
• Online Access: https://www.dovepress.com/severe-asthma-in-a-general-population-study-prevalence-and-clinical-ch-peer-reviewed-fulltext-article-JAA

Lina Rönnebjerg,1 Malin Axelsson,2 Hannu Kankaanranta,1,3,4 Helena Backman,5 Madeleine Rådinger,1 Bo Lundbäck,1 Linda Ekerljung1 1Krefting Research Centre, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; 2Department of Care Science, Faculty of Health and Society, Malmö University, Malmö, Sweden; 3Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland; 4Tampere University Respiratory Research Group, Faculty of Medicine and Health Technology, University of Tampere, Tampere, Finland; 5Department of Public Health and Clinical Medicine, Umeå University, Umeå, SwedenCorrespondence: Lina RönnebjergKrefting Research Centre, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, University of Gothenburg, Box 424, 405 30, Gothenburg, SwedenTel [phone]Email [e-mail]: 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 epidemiology, asthma control, asthma-medication, asthma severity symptoms, lung function