High prevalence of severe asthma in a large random population study

Publication date: Available online 20 September 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): Roxana Mincheva, Linda Ekerljung, Apostolos Bossios, Bo Lundbäck, Jan Lötvall
BackgroundThe prevalence of asthma severity is not well described at a population level.ObjectiveTo determine the prevalence of phenotypic signs of asthma severity among individuals with asthma in a general population, and to describe risk factors for asthma severity.MethodsEpidemiological study conducted between 2008 and 2012 (West Sweden Asthma Study). A postal questionnaire was sent to random population (N = 30,000) in West Sweden, with 18,087 responses. A total of 2,006 individuals were carefully phenotyped. Only individuals with "active asthma" (symptoms or medication in the last year, N = 744) were analyzed in this study, to determine degree of severity of the disease within an asthma cohort. Phenotypes of severity were calculated based on: 1) multiple symptoms during the day despite the ongoing use of asthma medications, 2) FEV1 below 70% of predicted value, 3) daily or almost daily use of rescue medications, 4) nighttime symptoms once a week or more, and 5) oral corticosteroid use/emergency room visits. Asthmatics were grouped as non-severe, one sign of severity or two or more signs of severity.ResultsA total of 36.2% of asthmatics expressed at least one sign of asthma severity, and 13.2% had two or more signs. The group with two or more signs was older in age, had higher BMI, a higher rate of tobacco smoking and lower lung function. Bronchial hyperreactivity, airway inflammation and sensitization were significantly different among the three groups. At a population level, the prevalence of asthma severity was 3.1% for one sign, and 1.3% for at least two signs.ConclusionMore than one in three asthmatics show at least one sign of asthma severity. The phenotypes of asthma severity are highly diverse, which is important to consider when implementing personalized medicine in asthma.Clinical implicationsOur data is based on a random population, which results in minimal bias vs patient selection, and argues that asthma severity is present in 13% to 36% of asthmatics.

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Teaser

Every third asthmatic showed at least one sign of asthma severity which indicates that there are still many unmet needs in managing this disease. Asthma severity phenotypes are very diverse prompting an individualized approach to patients.


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