Short-Acting Beta-2-Agonist Exposure and Severe Asthma Exacerbations: SABINA Findings From Europe and North America

Background: Expert national/global asthma management recommendations raise the issue whether a safe threshold of short-acting beta-2 agonist (SABA) use without concomitant inhaled corticosteroids (ICS) exists.

Objective: To examine SABA and maintenance therapy associations with severe asthma exacerbations across North America and Europe.

Methods: Observational analyses of 10 SABa use IN Asthma (SABINA) datasets involving 1,033,564 patients (≥12 y) from Canada, France, the Netherlands, Poland, Spain, the United Kingdom, and the United States. Negative binomial models (incidence rate ratio [IRR] [95% CI adjusted for prespecified-covariates]) evaluated associations between SABA and exacerbations.

Results: Across severities, 40.2% of patients were prescribed/possessed 3 or more SABA canisters/y. Per the Global Initiative for Asthma (GINA) 2018 definitions, steps 3 to 5-treated patients prescribed/possessing 3 or more versus 1 or 2 SABAs experienced more severe exacerbations (IRR 1.08 [95% CI 1.04‒1.13], U.S. Medicare; IRR 2.11 [95% CI 1.96‒2.27], Poland). This association was not observed in all step 1 or 2-treated patients (the Netherlands, IRR 1.25 [95% CI 0.91‒1.71]; U.S. commercial, IRR 0.92 [95% CI 0.91‒0.93]; U.S. Medicare, IRR 0.74 [95% CI 0.71‒0.76]). We hypothesize that this inverse association between SABA and severe exacerbations in the U.S. datasets was attributable to the large patient population possessing fewer than 3 SABA and no maintenance therapy and receiving oral corticosteroid bursts without face-to-face health care provider encounters. In U.S. SABA monotherapy-treated patients, 3 or more SABAs were associated with more emergency/outpatient visits and hospitalizations (IRR 1.31 [95% CI 1.29‒1.34]). Most GINA 2 to 5-treated study patients (60.6%) did not have maintenance therapy for up to 50% of the time; however, the association of 3 or more SABAs and severe exacerbations persisted (IRR 1.32 [95% CI 1.18‒1.49]) after excluding these patients and the independent effect was further confirmed when U.K. SABA data were analyzed as a continuous variable in patients with up to 100% annual coverage for ICS-containing medications.

Conclusions: Increasing SABA exposure is associated with severe exacerbation risk, independent of maintenance therapy. As addressed by GINA, based on studies across asthma severities where as-needed fast-acting bronchodilators with concomitant ICS decrease severe exacerbations compared with SABA, our findings highlight the importance of avoiding a rescue/reliever paradigm utilizing SABA monotherapy.