Prevalence of Comorbid Asthma and Related Outcomes in COVID-19: A Systematic Review and Meta-Analysis

Abstract

Background: The impact of asthma on coronavirus disease 2019 (COVID-19) remains largely unknown.

Objective: To investigate the asthma prevalence among patients with COVID-19 and compare outcomes between patients with and without asthma.

Methods: In this systematic review and meta-analysis, we searched PubMed, Embase, Web of Science, bioRxiv, and medRxiv for studies reporting asthma prevalence in general patients with COVID-19 or comparing outcomes between patients with and without asthma, and excluded duplicate publications, reviews, editorials, comments, single case reports, or small case series (<10 cases). We determined the pooled estimates of effect using random-effect model.

Results: On the basis of 131 studies (410,382 patients), we found great variability in the prevalence of comorbid asthma among patients with COVID-19 in different countries or regions ranging from 1.1% to 16.9%. No significant difference in asthma prevalence was found between hospitalized and nonhospitalized (risk ratio [RR], 1.15; 95% CI, 0.92-1.43), severe and nonsevere (RR, 1.21; 95% CI, 0.92-1.57), intensive care unit and non-intensive care unit (RR, 1.19; 95% CI, 0.92-1.54), dead and survived (RR, 0.90; 95% CI, 0.73-1.11), intubated/mechanically ventilated and nonintubated/mechanically ventilated (RR, 0.91; 95% CI, 0.71-1.17) patients with COVID-19. Patients with asthma have a lower risk of death compared with patients without asthma (RR, 0.65; 95% CI, 0.43-0.98). Asthma is not associated with a higher risk of intubation or mechanical ventilation (RR, 1.03; 95% CI, 0.72-1.46).

Conclusions: There is great variability in asthma prevalence among patients with COVID-19 in different countries or regions. Asthma is not associated with higher COVID-19 severity or worse prognosis, and patients with asthma are found to have a lower risk of death compared with patients without asthma.

Keywords: Asthma; COVID-19; Prevalence; Prognosis; Severity.

Figure 1

Study selection. PubMed, Embase, Web of Science, bioRxiv, and medRxiv databases were searched on July 21, 2020, for articles published since January 1, 2020. Another search was performed on August 18, 2020, to include eligible articles that were published between the 2 searches.

Figure 2

World map of asthma comorbidity rates in patients with COVID-19. The difference in asthma comorbidity rate is visualized as a colored world map, in which a darkening color represents higher prevalence. The asthma comorbidity rate was calculated as follows: for countries with 2 or more studies reporting the prevalence of asthma in patients with COVID-19, a meta-analysis was performed to estimate the pooled prevalence; for countries with only 1 study on asthma prevalence in patients with COVID-19, asthma prevalence was calculated as (total patients with COVID-19 with asthma)/(total patients with COVID-19).

Figure 3

Forest plots of the prevalence of comorbid asthma in patients with COVID-19 with different severity. (A) Forest plot of the prevalence of comorbid asthma in hospitalized and nonhospitalized patients with COVID-19. (B) Forest plot of the prevalence of comorbid asthma in severe and nonsevere patients with COVID-19. (C) Forest plot of the prevalence of comorbid asthma in patients with COVID-19 requiring and not requiring ICU admission. (D) Forest plot of the prevalence of comorbid asthma in dead and survived patients with COVID-19. (E) Forest plot of the prevalence of comorbid asthma in patients with COVID-19 requiring and not requiring intubation/mechanical ventilation.

Figure 4

COVID-19 outcomes in patients with and without asthma. (A) Forest plot of death risk in patients with COVID-19 with and without asthma. (B) Forest plot of intubation or mechanical ventilation need in patients with COVID-19 with and without asthma. MV, Mechanical ventilation.