Asthma does not appear to be a risk factor for severe COVID-19, an analysis of almost 17,000 UK patients who were admitted to hospital suggests.

The ISARIC4C study, which has yet to be peer-reviewed,  included COVID-19-positive patients admitted to 166 hospitals and is the largest detailed description of COVID-19 in Europe to date.

It found that a third of UK patients admitted to hospital with severe COVID-19 had underlying respiratory co-morbidities; 19% had non-asthmatic chronic pulmonary disease and 14% had asthma.

Other common co-morbidities include chronic cardiac disease which was present in 29% and uncomplicated diabetes in 19% of patients.

Patients who ended up in hospital had a median age of 72 and had symptoms for an average of four days before admission.

Overall 33% of patients included in the analysis died and among those needing intensive care the death rate was 45%, the analysis found.

Having a co-morbidity, being male, older and being overweight were all linked with an increased risk of death, the report concluded.

However, patients with asthma were not at increased risk of dying from the infection, the figures suggest.

Dr Nick Hopkinson, Reader in Respiratory Medicine at Imperial College and Honorary Consultant Chest Physician at The Royal Brompton Hospital said seeing that a third of patients had respiratory co-morbidities was not unexpected but the data was important.

“The interesting finding about asthma is that it is not associated with an increased risk of hospital mortality which suggests that it is not a risk factor for developing the more severe systemic problems, the inflammatory response. That seems to be a reasonable interpretation. And it is somewhat reassuring.”

But he said more detailed data may come at a later date, including what happens in patients with multiple chronic conditions.

“The other thing that is worth saying is that people with COPD have been advised to do full shielding and this suggests that there is indeed an excess risk.”