The relationship between asthma, eosinophilia, and outcomes in coronavirus disease 2019 infection

Background: The impact of asthma diagnosis and asthma endotype on outcomes from coronavirus disease 2019 (COVID-19) infection remains unclear. Objective: To describe the association between asthma diagnosis and endotype and clinical outcomes among patients diagnosed as having COVID-19 infection. Methods: Retrospective multicenter cohort study of outpatients and inpatients presenting to 6 hospitals in the Mount Sinai Health System New York metropolitan region between March 7, 2020, and June 7, 2020, with COVID-19 infection, with and without a history of asthma. The primary outcome evaluated was in-hospital mortality. Secondary outcomes included hospitalization, intensive care unit admission, mechanical ventilation, and hospital length of stay. The outcomes were compared in patients with or without asthma using a multivariate Cox regression model. The outcomes stratified by blood eosinophilia count were also evaluated. Results: Of 10,523 patients diagnosed as having COVID-19 infection, 4902 were hospitalized and 468 had a diagnosis of asthma (4.4%). When adjusted for COVID-19 disease severity, comorbidities, and concurrent therapies, patients with asthma had a lower mortality (adjusted odds ratio [OR], 0.64 (0.53-0.77); P <.001) and a lower rate of hospitalization and intensive care unit admission (OR, 0.43 (0.28-0.64); P <.001 and OR, 0.51 (0.41-0.64); P <.001, respectively). Those with blood eosinophils greater than or equal to 200 cells/μL, both with and without asthma, had lower mortality. Conclusion: Patients with asthma may be at a reduced risk of poor outcomes from COVID-19 infection. Eosinophilia, both in those with and without asthma, may be associated with reduced mortality risk.