Chaotic inhaler use may be a better red flag for at-risk patients than measuring their average total doses, according to an Australian proof-of-concept study.
Chaotic inhaler use may be a better red flag for at-risk patients than measuring their average total doses, according to an Australian proof-of-concept study.
The findings need validation in larger cohorts but may help in the design of more specific management plans for those with hard-to-treat disease.
Most work to-date focused on time-averaged measures – such as the total doses taken over those prescribed – and misses nuances in how patients take their medication, the authors said.
“[For example] a mean adherence rate of 50% cannot distinguish between one patient consistently taking half the prescribed dose daily and another taking the full prescribed dose, but for only half the required period,” they wrote in Nature Scientific Reports.
Over 50 days, they recorded the date and time of each actuation using electronic monitoring devices (EMDs) attached to the inhalers of 53 patients who had difficult-to-treat asthma.
They assessed entropy (a measure of disorder) using mathematical modelling developed by authors at the Woolcock Institute in Sydney.
They found that the more chaotic a patient’s inhaler use, the more likely they were to experience asthma attacks that necessitated a trip to their GP, oral corticosteroids or hospitalisation.
“We showed that disordered controller use in difficult-to-treat asthma …. reflected poor baseline asthma control and were associated with subsequent attacks of any severity,” they wrote.
Co-author Dr Joy Lee told Allergy and Respiratory Republic the idea of chaotic medication adherence had been looked at in other chronic medical conditions where patients were required to take long-term preventative treatment, such as cardiovascular disease and HIV infection, but to their knowledge this was the first time it had been applied to difficult-to-control asthma.
“Low adherence to inhaled preventers is a strong predictor of poor asthma control and poor outcomes, so what our study does is tease out more specific aspects of how the medication is taken,” Dr Lee, a respiratory specialist at Alfred Health in Melbourne with a special interest in allergic diseases, said.
Measuring entropy might prompt more discussion with patients of factors affecting their medication use, she added.
“We weren’t able to definitively demonstrate this, but it was a discussion point that chaotic inhaler use may be linked with other issues. In future studies we could look at other comorbidities such as anxiety, depression and socioeconomic status.
“Perhaps then we can develop more individualised strategies targeting the behaviours that will have the most impact.”
Scientific Reports 2021, 19 July
