Early severe asthma exacerbations affect disease course, future risk for attacks

Severe exacerbations that occur early in the course of asthma impacted the course of the disease and risk for subsequent exacerbations in children and adults, researchers reported in the Annals of the American Thoracic Society.

“This study identified substantial variability in severe exacerbation rates in both pediatric and adult patients with asthma with a history of severe asthma exacerbation,” Tae Yoon Lee, MD, from the Respiratory Evaluation Sciences Program, Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences at the University of British Columbia in Vancouver, Canada, and colleagues wrote. “It also showed that severe exacerbations early in the course of asthma are associated with an increase in the rate of subsequent events in both children and adults.”

The study focused on an incident cohort of 3,039 pediatric patients (mean age, 6.4 years; 35% girls) and 5,442 adult patients (mean age, 50.8 years; 68% women) with asthma, culled from administrated health databases in British Columbia, Canada, from January 1997 to March 2016. All patients had at least one asthma exacerbation requiring inpatient care. The researchers estimated the 5-year cumulative incidence of severe asthma exacerbation after successive previous events and evaluated the extent of between-individual variability in asthma exacerbation risk and links between each exacerbation with subsequent event rates.

After the first three asthma exacerbations, the 5-year rates of severe exacerbation were 0.16, 0.29 and 0.35 for children and 0.14, 0.33 and 0.49 for adults. The researchers observed substantial variability in patient-specific asthma exacerbation risks in both children and adults. The 5-year risk for severe asthma exacerbations in children ranged from 11% to 24% and in adults ranged from 8% to 40%, according to the results.

After controlling for potential confounders, researchers observed that the first follow-up asthma exacerbation was associated with a 79% increase in subsequent exacerbation event rates among children. This increase rose to 188% among adults.

According to the researchers, the mechanisms underlying these associations could not be elucidated.

“Besides offering a new insight into the natural history of asthma, these results can provide new evidence toward nuanced risk stratification of patients at risk of severe exacerbations,” the researchers wrote. “They can also have implications in quantifying the long-lasting benefit of interventions aimed at decreasing exacerbation rates or reducing exposure to extrinsic risk factors early in the course of asthma.”