Abstract:
Background: It is unclear if asthma and its allergic phenotype
are risk factors for hospitalization or severe disease from SARS-CoV-2.
Methods: All patients testing positive for SARS-CoV-2 between
March 1 and September 30, 2020, were retrospectively identified and
characterized through electronic analysis at Stanford. A sub-cohort was
followed prospectively to evaluate long-term COVID-19 symptoms.
Results: 168,190 patients underwent SARS-CoV-2 testing, and
6,976 (4.15%) tested positive. In a multivariate analysis, asthma was
not an independent risk factor for hospitalization (OR 1.12 [95% CI
0.86, 1.45], p=0.40). Among SARS-CoV-2 positive asthmatics, allergic
asthma lowered the risk of hospitalization and had a protective effect
compared to non-allergic asthma (OR 0.52 (0.28, 0.91), p=0.026); there
was no association between baseline medication use as characterized by
GINA and hospitalization risk. Patients with severe COVID-19 disease
had lower eosinophil levels during hospitalization compared to patients
with mild or asymptomatic disease, independent of asthma status
(p=0.0014). In a patient sub-cohort followed longitudinally, asthmatics
and non-asthmatics had similar time to resolution of COVID-19 symptoms,
particularly lower respiratory symptoms.
Conclusions: Asthma is not a risk factor for more severe
COVID-19 disease. Allergic asthmatics were half as likely to be
hospitalized with COVID-19 compared to non-allergic asthmatics. Lower
levels of eosinophil counts (allergic biomarkers) were associated with
more severe COVID-19 disease trajectory. Recovery was similar among
asthmatics and non-asthmatics with over 50% of patients reporting
ongoing lower respiratory symptoms three months post-infection.
Keywords: asthma, eosinophils; COVID-19, SARS CoV