Researchers have found that patients with asthma do not seem to be at risk from complications associated with being hospitalised with Covid-19 disease.

The study, published in the journal Annals of the American Thoracic Society, examined whether asthma is a significant risk factor for developing Covid-19 that is severe enough to warrant hospitalisation and intubation.

"The Centers for Disease Control and Prevention (CDC) places people with asthma at higher risk for Covid-related hospitalisation," said study researcher Fernando Holguin from the University of Colorado Anschutz in the US.

"However, many international studies show low numbers of asthmatics among hospitalised Covid-19 patients. These findings challenge the assumption about asthma as a risk factor," Holguin added.

For the findings, the research team compared the prevalence of asthma among patients hospitalised 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 hospitalisations in the US.

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 also performed a focused review of English-language scientific literature in order to identify studies reporting asthma prevalence among patients hospitalised for Covid-19 infection.

Three independent reviewers agreed on 15 studies to include in the analysis.

Using local data from hospitalised 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).

"We found that the proportion of asthmatics among hospitalised patients with Covid-19 is relatively similar to that of each study site's population asthma prevalence," the authors wrote.

This finding is in stark contrast to influenza, in which asthmatics make up more than 20 per cent of those hospitalised in the US," they added.

"Using data from our hospital, we also observed that among Covid-19 patients, those with asthma, which had a 12 per cent prevalence rate, did not seem to be more likely to be intubated than non-asthmatics," the team noted.

The research team theorised that the corticosteroid inhalers many people with asthma use make it more difficult for coronaviruses to enter their airways.