Treatable traits and exacerbation risk in patients with uncontrolled asthma prescribed GINA step 1–3 treatment : a nationwide asthma cohort study

Background and Objective: Uncontrolled asthma in patients treated for mild/moderate disease could be caused by non-pulmonary treatable traits (TTs) that affect asthma control negatively. We aimed to identify demographic characteristics, behavioural (smoking) and extrapulmonary (obesity, comorbidities) TTs and the risk for future exacerbations among patients with uncontrolled asthma prescribed step 1–3 treatment according to the Global Initiative for Asthma (GINA). Methods: Twenty-eight thousand five hundred eighty-four asthma patients (≥18 y) with a registration in the Swedish National Airway Register between 2017 and 2019 were included (index-date). The database was linked to other national registers to obtain information on prescribed drugs 2-years pre-index and exacerbations 1-year post-index. Asthma treatment was classified into step 1–3 or 4–5, and uncontrolled asthma was defined based on symptom control, exacerbations and lung function. Results: GINA step 1–3 included 17,318 patients, of which 9586 (55%) were uncontrolled (UCA 1–3). In adjusted analyses, UCA 1–3 was associated with female sex (OR 1.34, 95% CI 1.27–1.41), older age (1.00, 1.00–1.00), primary education (1.30, 1.20–1.40) and secondary education (1.19, 1.12–1.26), and TTs such as smoking (1.25, 1.15–1.36), obesity (1.23, 1.15–1.32), cardiovascular disease (1.12, 1.06–1.20) and depression/anxiety (1.13, 1.06–1.21). Furthermore, UCA 1–3 was associated with future exacerbations; oral corticosteroids (1.90, 1.74–2.09) and asthma hospitalization (2.55, 2.17–3.00), respectively, also when adjusted for treatment step 4–5. Conclusion: Over 50% of patients treated for mild/moderate asthma had an uncontrolled disease. Assessing and managing of TTs such as smoking, obesity and comorbidities should be conducted in a holistic manner, as these patients have an increased risk for future exacerbations.