SABA use as an indicator for asthma exacerbation risk: an observational cohort study (SABINA Canada).

Background: Patients with asthma use short-acting β-agonists (SABA) to relieve symptoms but SABA alone does not treat underlying inflammation. Thus, over-reliance on SABA may result in poor asthma control and negative health outcomes.
Objective: To describe use of SABA and characterise the relationship with severe exacerbations in the Canadian provinces of Nova Scotia (NS) and Alberta (AB).
Methods: In this longitudinal Canadian SABA In Asthma (SABINA) study, patients with an asthma diagnosis were identified between 2016 and 2020 within two provincial administrative datasets (Health Data Nova Scotia and Alberta Health Services). All patients were followed for ≥24 months, with the first 12 months used to measure baseline asthma severity. Medication use and the relationship of SABA overuse (three or more canisters per year) with severe asthma exacerbations were characterised descriptively and via regression analysis.
Results: A total of 115 478 patients were identified (NS: n=8034; AB: n=107 444). SABA overuse was substantial across both provinces (NS: 39.4%; AB: 28.0%) and across all baseline disease severity categories. Patients in NS with SABA overuse had a mean±sd annual rate of 0.46±1.11 exacerbations, compared to 0.30±1.36 for those using fewer than three canisters of SABA. Patients in AB had mean±sd exacerbation rates of 0.31±0.86 and 0.17±0.62, respectively. The adjusted risk of severe exacerbation was associated with SABA overuse (NS: incidence ratio rate 1.36, 95% CI 1.18-1.56; AB: incidence ratio rate 1.32, 95% CI 1.27-1.38).
Conclusion: This study supports recent updates to Canadian Thoracic Society and Global Initiative for Asthma guidelines for asthma care. SABA overuse is associated with increased risk of severe exacerbations and can be used to identify patients at a higher risk for severe exacerbations.
Competing Interests: Conflict of Interest: S.G. Noorduyn, M. Soliman and M. Talukdar are employees of AstraZeneca Canada Inc. C. Qian and K. Johnston are employees of Broadstreet HEOR, which received funds from AstraZeneca Canada Inc. for this work. B.L. Walker has received advisory board and speaker's honoraria from AstraZeneca, GlaxoSmithKline, Boehringer Ingelheim and Sanofi, unrelated to this work. P. Hernandez received funding from AstraZeneca to his institution and company for data acquisition and covered costs to conduct the study at the local site. He has received grants paid to his institution from Canadian Institute of Health Research, Boehringer Ingelheim, Cyclomedica, Grifols and Vertex, and received speaker honoraria from AstraZeneca, Boehringer Ingelheim and Janssen. He received honoraria from and participated in advisory boards for Acceleron, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Janssen, Novartis, Sanofi, Takeda, Teva and Valeo. He volunteered at Canadian Thoracic Society as an executive committee and Board member unrelated to this work. E. Penz has received research funds paid to her institution from AstraZeneca and Saskatchewan Cancer Agency, Canadian Institutes of Health Research, Saskatchewan Health Research Foundation and Respiratory Research Centre unrelated to this work. She has received consulting fees from GlaxoSmithKline, AstraZeneca and Sanofi Genzyme unrelated to this work. She received honoraria for participation on advisory boards, lecture series and educational events from AstraZeneca, GlaxoSmithKline, Sanofi, Boehringer Ingelheim and the International Centre for Evidence-Based Medicine, unrelated to this work. She is a Co-Chair of the COPD Assembly of Canadian Thoracic Society, Medical Lead at the Lung Cancer Screening Prevention Program, Saskatchewan Cancer Agency and a member of the Institute for Cancer Research Advisory Board, Canadian Institute for Health Research.
(Copyright ©The authors 2022.)