More frequent asthma exacerbations associated with rapid, long-term lung function decline

In a large study of people with asthma in the United Kingdom followed for up to 60 years, more frequent asthma exacerbations were associated with a faster decline in lung function, according to data published in Thorax.

“Our study provides the most robust estimate of year-on-year loss of lung function with increasing exacerbation burden for the average adult patient with asthma. We observed that the greater the annual exacerbation rate, the lower the starting lung function and the more negative the trajectory over time,” Seyi Soremekun, PhD, associate professor of epidemiology at the London School of Hygiene and Tropical Medicine, and colleagues wrote.

The cohort study included 109,182 adults with asthma (median age, 42 years; 40.9% men) from the Optimum Patient Care Research Database. All had three or more eligible peak expiratory flow rate records or records of FEV₁ as adults and had follow-up data ranging from 5 to 50 years. A total of 75,280 adults had data for all study variables for the adjusted analyses.

With every additional asthma exacerbation, researchers reported an additional –1.34 L per minute peak expiratory flow rate per year lost among patients (P < .001).

Compared with a loss of –0.02 L per minute peak expiratory flow rate per year among patients with no acute exacerbations, those with more than two acute exacerbations per year who were aged 18 to 24 years at baseline also lost an additional –5.95 L per minute, those with one to two acute exacerbations per year lost an additional –2.15 L per minute and those with up to one acute exacerbation per year lost an additional –0.77 L per minute. Researchers reported progressively smaller differences in the rate of lung function decline between these acute exacerbation groups as baseline age increased.

“A key new finding is that the greatest association of exacerbations is found in younger patients with lung function in the plateau or start of decline phase, and that while the association is much more modest in older patients, many have also already experienced significant decline in lung function, particularly among those with higher exacerbation burdens. This finding has important implications for earlier therapeutic intervention in frequently exacerbating patients prior to middle age before permanent deterioration in lung function has occurred,” the researchers wrote.

Results of a sensitivity analysis of 10,943 patients utilizing FEV₁, who were followed for a median of 8.1 years, were consistent with those in the adjusted analyses.

“Future analyses that further explore these associations under a causal framework and within other key subgroups of gender, ethnicity, location and other lifestyle factors will be highly valuable to address remaining evidence gaps,” the researchers wrote.