Long-term use of short-acting β2-agonists in patients with adult-onset asthma.

BACKGROUND

Short-term studies have associated high use of short-acting β2-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 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 (SAAS), 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/year.

RESULTS

Patients were dispensed median 6 (IQR 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 (BMI≥30) and high AQ20 (Airways Questionnaire 20) symptom scores at baseline predicted high long-term SABA use (IRR 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 vs. 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 recognised in clinical practice.