How does difficult-to-treat asthma impact the mental and physical health of Australian adults?

By addressing knowledge gaps about the prevalence, impacts and challenges of difficult-to-treat asthma, research by the Woolcock Institute of Medical Research aims to improve patient treatment and outcomes.

When you’re out of breath after running for the bus or sprinting for the goal post, it’s a relief when the thirst for air quickly subsides. But for a person with asthma, that shortage of breath may be more intense and last longer, or it may occur during a cold, out of the blue, or may be present most of the time. This is particularly true for those with difficult-to-treat asthma (DTTA), who continue to experience asthma symptoms or attacks despite taking preventer inhalers.

Little is known about the prevalence of difficult to treat asthma and how it affects physical and mental health, so the Woolcock Institute for Medical Research has undertaken a largescale survey studying this group of health consumers.

Impacts of difficult to treat asthma
Asthma affects around 2.8 million (or 11%) of Australians. This chronic (long-term) lung condition is caused by inflammation and narrowing of the airways. People with asthma experience symptoms such as wheezing, coughing, breathlessness and chest tightness.

“People with difficult to treat asthma attend health facilities, such as hospitals, more frequently because they have more frequent asthma attacks and near fatal asthma attacks, despite being prescribed a medium or high dose of inhaled preventive medication,” says Professor Helen Reddel, Research Leader in the Clinical Management Group at the Woolcock Institute of Medical Research, Chair of the Global Initiative for Asthma Science Committee and Director of the Australian Centre for Airways Disease Monitoring. “Our survey was designed to obtain more data about their symptoms, healthcare, self-care, additional health conditions, mental wellbeing and quality of life.”

Ensuring a wide survey sample
To conduct the national survey, Reddel and her team engaged a large survey platform which included almost one million people. Participants had no idea that the survey was about asthma. “We took this approach to capture a wide cross-section of people who would be representative of Australian adults with asthma,” Reddel explains. “In the past, research about difficult to treat asthma has often drawn information from asthma clinical trials or registries, where people who are more conscientious and engaged in their treatment may have been over-represented. Our survey approach enabled us to capture a broader cross-section, including individuals who did not have high levels of education or high levels of health literacy, or who live in rural and remote communities or who are from culturally and linguistically diverse backgrounds.”

Filling gaps in knowledge
The survey questions identified 6048 respondents with current asthma. Using criteria based on international and Australian guidelines, 21.7% of that cohort qualified as experiencing difficult-to-treat asthma. “We then asked them more details about their symptoms, frequency of asthma attacks, medications and dosage, lifestyle habits and other health conditions,” says Reddel. “We also inquired how often in the last year they had seen a GP or medical specialist for an urgent or non-urgent visit.”

A paper reporting the results was published in 2024. “This outlined our findings that people with difficult to treat asthma have a high level of uncontrolled symptoms, current smoking (36%), and multimorbidity (other health conditions),” Reddel says. “More than half were over-using common blue inhalers. This is concerning because over-use of these inhalers can make the inhaler less effective for relieving symptoms during an asthma attack.”

A second research paper is soon to be published and will expand on the survey findings that adults with difficult-to-treat asthma report higher levels of both anxiety and depression.

Helpful interventions
Reddel and her team hope that their research will guide future interventions for people with difficult-to-treat asthma in primary and specialist care to improve their symptoms and reduce their risk of asthma attacks. This will also help reduce public and private healthcare costs. “Even simple initiatives by GPs can bring huge benefits for these patients, such as checking the patient’s inhaler technique, treating other underlying conditions, and referring them to a specialist if asthma symptoms or attacks persist,” explains Reddel. “Prompt referral is particularly important because some people with difficult-to-treat asthma may benefit from new ‘biologic’ therapies, which reduce some specific types of inflammation in the airways.”

The survey findings indicated . “Asthma is in some ways, an invisible condition,” Reddel observes. “So, supporting people with difficult-to-treat asthma by maximising treatment options and education, will benefit their mental and physical health and quality of life in the short and long term.”

The Woolcock Institute for Medical Research were recently awarded funding under the NSW Government’s Medical Research Support Program. The funding, provided to eligible independent medical research institutions through the Office for Health and Medical Research, helps to cover research infrastructure costs to support a sustainable and highly productive medical research sector in NSW, including supporting the indirect cost for research projects such as this.