Impact of Asthma on Severity and Outcomes in COVID-19

BACKGROUND: We conducted this systematic review to evaluate whether asthma increases the risk of severe disease and adverse outcomes among subjects with COVID-19.

METHODS: We queried the PubMed and Embase databases for studies indexed through December 2020. We included studies providing data on severe disease, hospitalization, ICU care, need for mechanical ventilation, or mortality among subjects with COVID-19 with and without asthma. We calculated the relative risk for each reported outcome of interest and used random effects modeling to summarize the data.

RESULTS: We retrieved 1,832 citations, and included 90 studies, in our review. Most publications reported data retrieved from electronic records of retrospective subject cohorts. Only 25 studies were judged to be of high quality. Subjects with asthma and COVID-19 had a marginally higher risk of hospitalization (summary relative risk 1.13, 95% CI 1.03–1.24) but not for severe disease (summary relative risk 1.17, 95% CI 0.62–2.20), ICU admission (summary relative risk 1.13, 95% CI 0.96–1.32), mechanical ventilation (summary relative risk 1.05, 95% CI 0.85–1.29), or mortality (summary relative risk 0.92, 95% CI 0.82–1.04) as compared to subjects with COVID-19 without asthma.

CONCLUSIONS: Comorbid asthma increases risk of COVID-19-related hospitalization but not severe disease or other adverse outcomes in subjects with COVID-19.