Asthma Phenotypes and COVID-19 Risk: A Population-based Observational Study.

Bloom, Chloe I; Cullinan, Paul; Wedzicha, Jadwiga A

RATIONALE Studies have suggested some asthma patients are at risk of severe COVID-19, but they have had limited data on asthma phenotype and have not considered if risks are specific to COVID-19. OBJECTIVES Determine the effect of asthma phenotype on three levels of COVID-19 outcomes. Compare hospitalisation rates to influenza and pneumonia. METHODS Electronic medical records were used to identify asthma patients and match them to the general population. Patient-level data were linked to Public Health England SARS-CoV-2 test data, hospital, and mortality data. Asthma was phenotyped by medication, exacerbation history, and type-2 inflammation. The risk of each outcome, adjusted for major risk factors, was measured using Cox regression. MEASUREMENTS AND MAIN RESULTS 434,348 asthma and 748,327 matched patients were included. All asthma patients had a significantly increased risk of a GP-diagnosis of COVID-19. Asthma with regular inhaled corticosteroid (ICS) use (HR=1.27, 95%CI=1.01-1.61), intermittent ICS + add-on asthma medication use (HR=2.00, 95%CI=1.43-2.79), regular ICS + add-on use (HR=1.63, 95 CI=1.37-1.94), or with frequent exacerbations (HR=1.82, 95% CI=1.34-2.47) was significantly associated with hospitalisation. These phenotypes were significantly associated with influenza and pneumonia hospitalisations. Only patients with regular ICS + add-on asthma therapy (HR=1.70, 95%CI=1.27-2.26) or frequent exacerbations (HR=1.66, 95%CI=1.03-2.68) had a significantly higher risk of ICU admission or death. Atopy and blood eosinophil count were not associated with severe COVID-19 outcomes. CONCLUSIONS More severe asthma was associated with more severe COVID-19 outcomes, but type-2 inflammation was not. The risk of COVID-19 hospitalisation appeared to be similar to the risk with influenza or pneumonia. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).