Reliever inhalers used more on days with high wildfire-related air pollution

Key takeaways:

• Use of reliever inhalers went up on days with unhealthy air quality levels around the time of the Canadian wildfires.
• Usage was captured with a digital inhaler.

ANAHEIM, Calif. —Patients with asthma used reliever inhalers more on days with unhealthy air quality during the Canadian wildfires, according to a poster at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.

“Air pollution by wildfire smoke has been associated with asthma symptom worsening, exacerbations and an increased number of visits to the emergency department,” Autumn F. Burnette, MD, FACAAI, assistant professor in the division of allergy and immunology at Howard University Hospital, said during her presentation. “This summer’s wildfires in Canada had a severe impact on air quality in the north and northeast United States.”

In a retrospective analysis, Burnette and colleagues evaluated 14 patients with asthma who lived in a region affected by the Canadian wildfires between May 28 and June 17, 2023, to assess patterns of short-acting beta agonist (SABA) inhaler usage through the Digihaler (Teva Pharmaceuticals) electronic inhaler that collects user data. These data are available to patients through an app and to clinicians through a web-based dashboard.

Within the timeframe, patients had to use the Digihaler a minimum of one time, Burnette said.

To chart poor air quality, researchers used a public source to find air quality index (AQI) data for each patient’s place of residence.

Researchers determined changes in daily reliever inhaler use by comparing usage from the week most impacted by wildfires (June 4 to June 10) to average usage during the prior and following weeks, which served as baseline, and then looked at how these changes related to the daily AQI.

From June 6 to June 8, air quality was deemed either unhealthy for sensitive groups (average AQI, 101-150) or unhealthy (average AQI, 151-200).

Researchers observed a nearly 500% daily change from baseline reliever use on June 8. Notably, this was the highest daily change from baseline reliever use recorded within the timeframe, but June 7 and June 9 had changes around 200%.

“[The] findings are strongly suggestive of a causal relationship between wildfire-associated air pollution and increased reliever use, reflecting worsening of asthma symptoms,” Burnette said during her presentation. “Data from the Digihaler system can provide valuable insight into the impact of localized environmental events such as wildfires on individual disease status and could support preemptive clinical intervention.”