- Poor symptom control
- Frequent severe exacerbations / flare-ups / attacks
- Serious exacerbations (e.g. hospitalisation, ICU stay or mechanical ventilation)
- Airflow limitation or
- Controlled asthma that worsens on tapering of corticosteroid treatment
It is estimated that between 3-10% of people with asthma have severe disease. Severe asthma is serious problem and a major concern. Severe asthma puts a very heavy burden on individuals and their families (Foster et al. 2017) and on the health system (Sadatsafavi et al. 2010). For more information see the Prevalence & Burden section.
Figure based on data from the Netherlands (Hekking et al. 2015)
Not all asthma is the same. Around 3-10% of people with asthma have severe disease. People with severe asthma have symptoms and attacks even when taking high-dose medication. Severe asthma has a major impact on their lives. Symptoms include difficulty breathing, wheezing and coughing. Asthma attacks can lead to hospitalisation and even death. Severe asthma also has an emotional burden. People with severe asthma have high rates of anxiety and depression. Severe asthma also has a major cost on society. Severe asthma reduces people’s ability to work and is a major healthcare cost.
Not all asthma is the same. Most people with asthma experience mild to moderate symptoms, and respond well to standard preventer therapies. Some people continue to experience poor symptom control or attacks/flare-ups, despite being prescribed maximum doses of preventer medication. For many of these patients, this is because of problems that may be addressed, this is termed ‘difficult-to-treat asthma’. When these factors are managed effectively, some people continue to have frequent symptoms or frequent attacks/flare-ups. This is called ‘severe asthma’ or ‘severe treatment-refractory asthma’.
People with severe asthma experience ongoing symptoms. In Australia, about 45% of adults with a diagnosis of asthma have frequent symptoms (called poor symptom control), and about one quarter need to have an urgent visit to their doctor or to a hospital in a year, because of their asthma (Reddel et al. 2015).
People with severe asthma experience frequent worsening of symptoms, termed attacks, flare-ups or exacerbations, which can lead to hospitalisation or even death.
Asthma differs between individuals due to different underlying disease mechanisms. Identifying the disease mechanisms that are active in an individual patient can be predictive of responses to targeted therapy.
Key features of severe asthma pathology include airway inflammation, airway hyper-responsiveness, airway remodelling and mucous hypersecretion.