Prevalence and Risk of Severe Asthma in Adult Patients with COVID-19

Rationale: As of December 7, 2020, there have been over 66 million confirmed cases of COVID-19 worldwide and over 1.5 million deaths attributed to the pandemic. Health outcomes of people with COVID-19 range from no symptoms to severe illness and death. Asthma is a highly prevalent chronic inflammatory disease of the airways that afflicts over 330 million people worldwide. Because SARS-CoV-2 is primarily a respiratory virus, people with asthma are apprehensive that they may be at increased risk of acquiring COVID-19 and suffer poorer outcomes. However, data addressing this hypothesis have been scarce until very recently. Methods: We reviewed the epidemiologic literature related to asthma's potential role in COVID-19 severity. Studies were identified through the PubMed and medRxiv databases, and by cross-referencing citations in identified studies, available in print or online before October 8, 2020. Asthma prevalence data were obtained from studies of people with confirmed COVID-19. Meta-analyses were conducted to produce weighted pooled prevalence ratios (PR) of asthma for hospitalized versus non-hospitalized participants, those with severe COVID-19 versus non-severe COVID-19, and those who died vs. survived. Results: Eleven studies provided data on the prevalence of asthma in people who were hospitalized with COVID-19 and those who were deemed well enough to be sent home with the disease (Table 1). The prevalence of asthma in these two groups was 8.5% (95% CI=6.4-10.9) and 8.2% (95% CI=6.8-9.8), respectively. The pooled PR for hospitalized individuals vs. those not hospitalized was 0.94 (0.78-1.12), p=0.49. Likewise, twenty-four studies provided data on asthma prevalence among patients hospitalized with COVID-19 according to disease severity (Table 1). The prevalence of asthma in patients with “severe” and “not severe” COVID-19 was 8.2% (95% CI=6.2-10.5) and 7.0% (95% CI=5.8-8.3), respectively. The pooled PR for asthma according to COVID-19 severity was 1.10 (95% CI=0.90-1.35, p=0.35). Twelve studies provided data from those who either died of COVID-19 or survived (Table 1). The prevalence of asthma in these two groups was 6.1% (95% CI=3.8-8.9) and 7.5% (95% CI=5.3-10.0), respectively. The pooled PR for asthma among patients who died from COVID-19 vs. those who survived was 0.76 (0.52-1.10, p=0.15). Conclusions: The results of our analyses do not provide clear evidence of increased risk of COVID-19 diagnosis, hospitalization or severity, due to asthma. These findings should provide some reassurance to people with asthma regarding the novel coronavirus and its potential to increase their risk of severe morbidity from COVID.