Written by: Prof. Zuzana Diamant Affiliations: Skane University Hospital Lund, Sweden and University Medical Center Groningen, the Netherlands
Asthma is a highly prevalent disorder associated with comorbidities, affecting over 350 million people worldwide and imposing a significant health and socioeconomic burden . In 2015, as many as 400,000 asthma deaths have been reported .
Traditionally, asthma is diagnosed by (a history of) symptoms including wheeze, dyspnoea, chest tightness, and/or cough in combination with variable, often reversible, airway narrowing. Hallmarks of asthma underlying its clinical presentation include chronic airway inflammation, airway hyperresponsiveness, and structural changes within the airways referred to as ‘’airway remodelling’’. These characteristics are interrelated and have been shown to be more prominently present in uncontrolled disease . Indeed, severe exacerbations reflecting an intense flair-up of the airway inflammation have been found to cause an accelerated decline in lung function in patients with more severe asthma [3,4]. This underscores the vital importance of reaching optimal asthma control and preventing exacerbations.
Despite increased awareness, patient counselling, implementation of comprehensive, evidence-based guidelines, and recent advances in pharmacological treatment options, data from studies and surveys demonstrate that the vast majority of asthma patients are inadequately controlled [5-7]. According to some studies, the percentage of uncontrolled asthmatic patients in Europe amounts up to 45% . Apart from externally contributing factors such as non-adherence to treatments, inadequate inhalation technique, life style, and environmental triggers, some asthma subtypes (especially severe asthma) may be truly difficult to control due to its heterogeneous nature and (relative) unresponsiveness to standard pharmacological treatment [9,10].
Patients with severe asthma, defined as those requiring treatment with high-dosed inhaled corticosteroids (ICS) plus a second controller and/or systemic corticosteroids (after other causes for lack of control, including adherence, inhalation technique, and comorbidities have been addressed), comprise approximately 5-10% of the entire asthma population but account for >80% of the total healthcare costs of asthma . To aid the development of targeted treatment options, there is an urgent need to identify precipitating factors and inflammatory pathways of distinct subphenotypes of severe asthma.
- Global Strategy for Asthma Management and Prevention. 2018 GINA Report.
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- Price D, et al. NPJ Prim Care Respir Med. 2014;24:14009.
- Chung KF, et al. Eur Respir J. 2014;43(2):343-73.
- Israel E, Reddel HK. New Engl J Med. 2017;377(10):965-76.
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