Uncontrolled asthma predicts severe COVID-19: a report from the Swedish National Airway Register

Abstract

Background: Severe asthma increases the risk of severe COVID-19 outcomes such as hospitalization and death. However, more studies are needed to understand the association between asthma and severe COVID-19. Methods: A cohort of 150,430 adult asthma patients were identified in the Swedish National Airway Register (SNAR) from 2013 to December 2020. Data on body mass index, smoking habits, lung function, and asthma control test (ACT) were obtained from SNAR, and uncontrolled asthma was defined as ACT ⩽19. Patients with severe COVID-19 were identified following hospitalization or in death certificates based on ICD-10 codes U07.1 and U07.2. The Swedish Prescribed Drug register was used to identify comorbidities and data from Statistics Sweden for educational level. Multivariate logistic regression analyses were used to estimate associations with severe COVID-19. Results: Severe COVID-19 was identified in 1067 patients (0.7%). Older age (OR = 1.04, 95% CI = 1.03–1.04), male sex (1.42, 1.25–1.61), overweight (1.56, 1.27–1.91), obesity (2.12, 1.73–2.60), high-dose inhaled corticosteroids in combination with long-acting β-agonists (1.40, 1.22–1.60), dispensed oral corticosteroids ⩾2 (1.48, 1.25–1.75), uncontrolled asthma (1.64, 1.35–2.00), cardiovascular disease (1.20, 1.03–1.40), depression (1.47, 1.28–1.68), and diabetes (1.52, 1.29–1.78) were associated with severe COVID-19, while current smoking was inversely associated (0.63, 0.47–0.85). When comparing patients who died from COVID-19 with those discharged alive from hospital until 31 December 2020, older age, male sex, and current smoking were associated with COVID-19 death. Conclusion: Patients with uncontrolled asthma and high disease burden, including increased asthma medication intensity, should be identified as risk patients for severe COVID-19. Furthermore, current smoking is strongly associated with COVID-19 death in asthma.

Different effect of inhaled and systemic corticosteroids on the outcome of COVID-19 among patients with asthma

“…One study using Swedish National Airway Register showed that patients with uncontrolled asthma and high disease burden, including increased asthma medication intensity, would be associated with an increased risk of severe COVID-19. 6 Similar findings were demonstrated in another national incident cohort study in Scotland. 3 …”

The association of preexisting severe asthma with COVID-19 outcomes

“…Our search yielded nine studies that quantified the association between severe asthma and poor COVID-19 outcomes (Table 1 ) [ 16 , 17 ▪ , 18 ▪ , 19 – 23 , 24 ▪ ]. Each of these studies used a unique definition of severe asthma, based on: the number and/or type of medicines used to control asthma, the Global Initiative for Asthma (GINA) severity level, recent history of severe asthma exacerbation, or an Asthma Control Test (ACT) score ≤19, the latter a measure of uncontrolled asthma.…”

“…Data from 14 studies that examined COVID-19 showed mixed results (Fig. 3 ) [ 17 ▪ , 18 ▪ , 22 , 23 , 24 ▪ , 26 , 30 – 37 ]. ICS use in patients with asthma was associated with increased odds (OR = 1.20, 1.08–1.34) of COVID-19 (nonfatal) severity, but decreased odds of COVID-19 mortality (OR = 0.89, 95% CI 0.86–0.92).…”

Effect of SARS-CoV-2 infection on asthma patients

“…Airway remodeling is an essential feature of asthma, manifested by structural changes in the airways, such as basement membrane thickening, bronchial fibrosis, airway smooth muscle cell hyperplasia, and hypertrophy ( 6 – 8 ). Among COVID-19 patients, uncontrolled asthma was identified as contributing factor to mortality, and patients also had more severe asthma manifestations during the pandemic ( 9 , 10 ). Therefore, considering the current COVID-19 epidemic and the high prevalence of asthma, the study results are timely.…”