Predictors of severe COVID-19 among patients with uncontrolled asthma: a register- based study

ABSTRACT

Background: Uncontrolled asthma is a risk factor for severe COVID-19. However, research on predictors of severe COVID-19 in patients with a history of uncontrolled asthma is still limited. Aim(s) To identify factors associated with severe COVID-19 in patients with uncontrolled asthma. Method(s) Based on the Swedish National Airway Register, a cohort of 24533 adult patients with uncontrolled asthma were identified in primary and secondary care. Most recent clinical data were obtained before the COVID-19 pandemic. Uncontrolled asthma was defined as Asthma Control Test (ACT) score <=19. By linkage to other Swedish registers, n=221 (0.9%) individuals with severe COVID-19 were identified (defined as hospitalization or death due to COVID-19). Result(s) Patients with severe COVID-19 (n=221) were older (mean 63.3 vs 50.4 years, p<0.001), had a higher BMI (mean 32.9 vs 28.6, p<0.001), lower FEV1 % predicted (mean 76.8 vs. 83.1, p<0.001) and lower ACT scores (mean 14.2 vs 15.2, p<0.001) than those without severe COVID-19 (n=24312). A higher proportion of patients with severe COVID-19 had antihistamine treatment, oral corticosteroids medication, and higher doses of inhaled corticosteroids, compared to patients without severe COVID-19. In both groups, about 50% had received patient education on asthma. Conclusion(s) Among patients with uncontrolled asthma, severe COVID-19 was associated with a history of increased need for asthma medication and lower FEV1 % predicted. Despite all patients having uncontrolled asthma, only about half had received patient education on asthma before the pandemic.