A study published in the journal Annals of the American Thoracic Society has examined whether asthma served as an important risk factor in the development of COVID-19 that may require mandatory hospitalization and intubation.

Dr. Fernando Holguin, the study author said in a statement, "The CDC places people with asthma at higher risk for COVID-related hospitalization. However, many international studies show low numbers of asthmatics among hospitalized COVID-19 patients. These findings challenge the assumption about asthma as a risk factor."

CDC's Take on Asthma Risk

USA COVID-19
USA COVID-19 (Representational Picture) Pexels/Karolina Grabowska

According to the Centers for Disease Control and Prevention, individuals with asthma are at higher risk for hospitalization and other severe effects from COVID-19, similar to the elevated risk from such health conditions as obesity, hypertension and diabetes.

In the study, Dr. Holguin and his colleagues compared the prevalence of asthma among patients hospitalized for COVID-19, as reported in 15 peer-reviewed studies, with that of the corresponding population's asthma prevalence. They also correlated the study's asthma prevalence with the four-year average asthma prevalence in influenza hospitalizations in the United States.

In addition, they analyzed the medical records of 436 COVID-19 patients admitted to the University of Colorado Hospital to evaluate the likelihood that patients with asthma would be intubated more often than patients without asthma. The researchers performed a focused review of English-language scientific literature in order to identify studies reporting asthma prevalence among patients hospitalized for COVID-19 infection.

Three independent reviewers agreed on 15 studies to include in the analysis. Using local data from hospitalized COVID-19 patients, they performed a statistical analysis to determine the relationship between asthma status and intubation, once they took into account patients' age, gender and body mass index (BMI).

Need to Study Link Further

The authors stated, "We found that the proportion of asthmatics among hospitalized patients with COVID-19 is relatively similar to that of each study site's population asthma prevalence. This finding is in stark contrast to influenza, in which asthmatics make up more than 20 percent of those hospitalized in the United States."

"Using data from our hospital, we also observed that among COVID-19 patients, those with asthma, which had a 12 percent prevalence rate, did not seem to be more likely to be intubated than non-asthmatics," they added. Dr. Holguin and colleagues theorize that the corticosteroid inhalers many people with asthma use make it more difficult for coronaviruses to enter their airways.

Specifically, these individuals may have lower levels of expression of ACE2, a protein that binds to SARS-CoV-2, the virus caused by COVID-19. People with asthma that is related to allergies may also have lower expression of ACE2, whether or not they use corticosteroids. "The contribution of ACE2 receptor expression levels to COVID-19 susceptibility is still unclear, however, it should certainly be further investigated," said Dr. Holguin. Dr. Holguin adds that the asthma-COVID-intubation risk relationship should be studied further.

(With inputs from agencies)