Long-Term Use of Short-Acting β-Agonists in Patients With Adult-Onset Asthma.

Background: Short-term studies have associated high use of short-acting β-agonists (SABA) with increased risk of exacerbations, emergency visits, and asthma-related costs. However, no studies exist on long-term SABA use, and previous studies on the topic have not included information about adherence to inhaled corticosteroids (ICS) nor disease control, both affecting the need of SABA.

Objective: To evaluate the clinical characteristics of SABA and ICS usage in newly diagnosed adult-onset asthma patients during a 12-year follow-up period.

Methods: In the Seinäjoki Adult Asthma Study, 203 patients with adult-onset asthma were followed for 12 years. Information on dispensed SABA and ICS during the follow-up was obtained from the Finnish Social Insurance Institution. High SABA use was defined as ≥36 canisters in 12 years, corresponding to an average of ≥3 dispensed canisters/y.

Results: Patients were dispensed median 6 (interquartile range: 3-16) SABA canisters and 48 (18-67) ICS canisters over 12 years, corresponding to 2 (1-4) and 11 (5-16) puffs/week, respectively. Only 10% of the patients were classified as high SABA users during this period. Obesity (body mass index ≥30) and high Airways Questionnaire 20 symptom scores at baseline predicted high long-term SABA use (incidence rate ratio: 1.53 [1.01-2.30] and 1.04 [1.00-1.08], respectively). High SABA users had higher ICS adherence, higher blood neutrophil counts, more comorbidities, and used more oral corticosteroid and antibiotic courses versus low SABA users.

Conclusion: High SABA use was infrequent in patients with confirmed adult-onset asthma. However, as high SABA use is associated with more severe asthma, these patients should be recognized in clinical practice.