Survivors of Melbourne’s thunderstorm asthma event of 2016 are experiencing persistent  symptoms that suggest worsening in disease trajectory and loss of asthma control, researchers say

One year after being affected by the  epidemic thunderstorm asthma event, most patients had a “pivotal shift” to ongoing asthma symptoms, which appeared to be poorly controlled due to low use of preventer inhalers, according to findings of the first major follow up study.

In a 12-month prospective observational study researchers from Box Hill Hospital, Eastern Health and Monash University followed up 442 people who had been treated in emergency departments  for thunderstorm asthma in 2016.

They found that 80% (349) reported ongoing asthma symptoms, of whom 28% (96) had persistent asthma – defined as symptoms at least once a week.

About half of the people (53%) with thunderstorm asthma followed up at one year had been prescribed inhaled preventers, and only half of these (51%) were adherent at least 5 days a week.

Similarly, only 42% of survivors had a written asthma action plan and of those followed up, 16% had again sought urgent medical attention for asthma in the preceding year.

The risk of persistent asthma was significantly higher in those who had a prior asthma diagnosis, current asthma, and probable undiagnosed asthma.

Writing in the Asia Pacific Allergy journal, the researchers – including Professor Frank Thien said the findings provided the first insights into the natural history of individuals affected by thunderstorm asthma, and a worrying  trend for undertreatment.

“Importantly, our data suggests a loss of asthma control in those with previously well-controlled asthma, and the development of symptoms suggestive of de novo asthma in those with no history or symptoms suggestive of prior asthma,” they wrote.

“Moreover, there were low rates of inhaled preventer use and asthma action plan ownership among the group, even in those reporting ‘persistent’ symptoms.”

They said that the pivotal change seen in asthma trajectory may be a late asthmatic response to a high level of inhaled allergen.

“From our data, we hypothesize that [epidemic thunderstorm asthma] constitutes a massive small airways allergen challenge inducing persistent airway inflammation with nonspecific bronchial hyperresponsiveness.

However, this is speculative and requires further evaluation of the persistence of airway inflammation with measures such as fractional exhaled nitric oxide and other tests of nonspecific bronchial hyperresponsiveness.”