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

Abstract

RationaleStudies have suggested some patients with asthma are at risk of severe coronavirus disease (COVID-19), but they have had limited data on asthma phenotype and have not considered if risks are specific to COVID-19.ObjectivesTo determine the effect of asthma phenotype on three levels of COVID-19 outcomes. Compare hospitalization rates with influenza and pneumonia.MethodsElectronic medical records were used to identify patients with asthma and match them to the general population. Patient-level data were linked to Public Health England severe acute respiratory syndrome coronavirus 2 (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 ResultsA total of 434,348 patients with asthma and 748,327 matched patients were included. All patients with asthma had a significantly increased risk of a General Practice diagnosis of COVID-19. Asthma with regular inhaled corticosteroid (ICS) use (hazard ratio [HR], 1.27; 95% confidence interval [CI], 1.01–1.61), intermittent ICS plus add-on asthma medication use (HR, 2.00; 95% CI, 1.43–2.79), regular ICS plus 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 hospitalization. These phenotypes were significantly associated with influenza and pneumonia hospitalizations. Only patients with regular ICS plus 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.ConclusionsMore severe asthma was associated with more severe COVID-19 outcomes, but type 2 inflammation was not. The risk of COVID-19 hospitalization appeared to be similar to the risk with influenza or pneumonia.