People with asthma have only a modestly increased risk of developing severe Covid-19 and requiring admission to hospital from the illness, according to an analysis of 8.3 million electronic health care records in England led by researchers at the University of Oxford.
The study published in the journal The Lancet Respiratory Medicine examined routine patient data collected between January to April 2020 to generate risk assessments for severe Covid-19 in people with chronic respiratory diseases.
Covid-19 and asthma
Unlike previous studies of people hospitalised with Covid-19, which suggest large increases in risk associated with underlying respiratory disease, this analysis demonstrated that the risk of severe Covid-19 was only modestly raised over the risk in people without such conditions.
The analysis reviewed several respiratory diseases and included data from 1.09 million people with asthma, 193,520 people with chronic obstructive pulmonary disease and 5,677 people with other interstitial lung disease. It compared the risks in these groups to seven million people without respiratory diseases.
When adjusted for age, sex, demographic factors, underlying health conditions and compared with those without respiratory diseases, people with active asthma and severe asthma were at 26% and 29% higher relative risk of hospital admission with Covid-19, respectively, and around 30% higher relative risk of admission to intensive care.
There was no evidence that asthma was associated with an increased absolute risk of death from Covid-19, and the risks appeared similar for all ethnicities, it argued.
Having chronic obstructive pulmonary disease (COPD) was associated with a 50% increased risk of hospitalisation and 54% increased risk of death from Covid-19, which was higher in those with white ethnicity.
In patients with interstitial disease, a group of less common lung diseases which cause scarring of the lung tissue, the analysis shows a 30–50% increased relative risk of developing severe Covid-19 requiring hospital admission or leading to death. Patients in this group are currently advised to shield.
Though a concern for many, the risk of “long Covid” in people with respiratory disease was not determined in this study, the researchers added.
Lead researcher Professor Paul Aveyard, a general practitioner and Professor of Behavioural Medicine in the University of Oxford’s Nuffield Department of Primary Care Health Sciences said: “At the start of the pandemic, the assumption that pre-existing respiratory disease would lead to an increased risk of serious Covid-19 illness was reasonable.
“Covid-19 has quite rightly caused much anxiety in people with respiratory disease and, while our results do show this group are at higher risk from developing severe Covid-19, when you put this into context with other known risk factors for hospitalisation, the relative risk for those with chronic respiratory disease are lower than the risks from being male or having diabetes, and are a small fraction of the everyday risk of death from any cause.
“Our analysis suggests that the risk of hospital admission from severe Covid-19 in a person with asthma is equivalent to the risk for people without asthma who are three to five years older. For people with COPD or interstitial lung disease, their risk would be equivalent to the risk for people without these conditions who are seven to eight years older.”
The study also provided further evidence that the use of inhaled corticosteroids in those with airways diseases is not associated with substantial increased risk of severe Covid-19, but neither does it appear to be linked to reduced risk.