Asthma Not Associated with Poorer Outcomes in Hospitalized COVID-19 Patients
Key findings
- Recent reports suggest asthma is not overrepresented among patients with severe COVID-19, but most of those studies included patients who had concomitant pulmonary conditions
- This matched cohort study compared outcomes of 80 inpatients with COVID-19 who had asthma and no other chronic pulmonary disease, and 323 inpatients with COVID-19 who did not have asthma or other chronic pulmonary disease
- Asthma patients were 48% less likely than comparators to require ICU admission, 58% less likely to require mechanical ventilation and they were not at increased risk for death
Asthma exacerbations can be triggered by viral respiratory infections, and the CDC says people with asthma might be at increased risk of severe illness if they become infected with SARS-CoV-2, the virus that can cause COVID-19.
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Recent reports suggest asthma is not overrepresented among patients with severe COVID-19, but most of those studies included patients who had additional pulmonary conditions, such as chronic obstructive pulmonary disease, that might have confounded the results.
Lacey B. Robinson, MD, assistant in Medicine, and Kimberly G. Blumenthal, MD, MSc, Quality and Safety officer forAllergy and co-director of the Clinical Epidemiology Program in the Division of Rheumatology Allergy and Immunology at Massachusetts General Hospital, and colleagues recently performed a matched cohort study in which they used strict criteria for an asthma diagnosis and excluded patients with other chronic lung diseases. In a letter to the editor of The Journal of Allergy and Clinical Immunology: In Practice, they say their findings do not suggest asthma increases the risk of severe outcomes in COVID-19.
Study Methods
Using the MGH COVID-19 Data Registry, the researchers identified 80 adults who were hospitalized at Mass General for COVID-19 between March 8 and April 27, 2020, and also had a diagnosis of asthma, verified by a board-certified allergist/immunologist. For each COVID-19 asthma inpatient, the team identified up to five inpatients, matched on age, sex and date of positive COVID-19 test, who had COVID-19 but not asthma.
The 80 asthma patients and 323 comparators were cared for with the same treatment protocols, and there was no approved treatment at the time of this study.
Primary Outcomes
- ICU admission: 24% of asthma patients and 33% of comparators
- Mechanical ventilation: 15% of asthma patients and 28% of comparators
- Death: 9% of asthma patients and 12% of comparators
All seven asthma patients who died had at least two substantial comorbidities, including four who had dementia/cognitive impairment that had influenced prior asthma treatment and code status.
Multivariable Analyses
- 48% lower risk of ICU admission among asthma patients than comparators (adjusted HR, 0.52; 95% CI, 0.30–0.90)
- 58% lower risk of mechanical ventilation among asthma patients than comparators (adjusted HR, 0.42; 95% CI, 0.21–0.81)
- No difference between groups in risk of death
Why patients with asthma seem to have a reduced risk of ICU admission and mechanical ventilation is currently unknown. One potential explanation is immune alterations associated with asthma and allergy, including decreased expression of ACE2, the receptor required for SARS-CoV-2 entry into human cells.
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