Relationship between asthma and severe COVID-19: a national cohort study

Abstract

Background: We aimed to determine whether children and adults with poorly controlled or more severe asthma have greater risk of hospitalisation and/or death from COVID-19.

Methods: We used individual-level data from the Office for National Statistics Public Health Data Asset, based on the 2011 census in England, and the General Practice Extraction Service data for pandemic planning and research linked to death registration records and Hospital Episode Statistics admission data. Adults were followed from 1 January 2020 to 30 September 2021 for hospitalisation or death from COVID-19. For children, only hospitalisation was included.

Results: Our cohort comprised 35 202 533 adults and 2 996 503 children aged 12-17 years. After controlling for sociodemographic factors, pre-existing health conditions and vaccine status, the risk of death involving COVID-19 for adults with asthma prescribed low dose inhaled corticosteroids (ICS) was not significantly different from those without asthma. Adults with asthma prescribed medium and high dosage ICS had an elevated risk of COVID-19 death; HRs 1.18 (95% CI 1.14 to 1.23) and 1.36 (95% CI 1.28 to 1.44), respectively. A similar pattern was observed for COVID-19 hospitalisation; fully adjusted HRs 1.53 (95% CI 1.50 to 1.56) and 1.52 (95% CI 1.46 to 1.56) for adults with asthma prescribed medium and high-dosage ICS, respectively. Risk of hospitalisation was greater for children with asthma prescribed one (2.58 (95% CI 1.82 to 3.66)) or two or more (3.80 (95% CI 2.41 to 5.95)) courses of oral corticosteroids in the year prior to the pandemic.

Discussion: People with mild and/or well-controlled asthma are neither at significantly increased risk of hospitalisation with nor more likely to die from COVID-19 than adults without asthma.

Keywords: COVID-19; asthma.

Figure 1

Adjusted HRs of death involving COVID-19 in adults for different asthma status compared with people with no asthma. HRs of death involving COVID-19 compared with people with no asthma, obtained from Cox regression models. Sociodemographic factors include, region, ethnicity, quintile of the Index of Multiple Deprivation; health conditions include relevant pre-existing conditions, defined as per in the QCovid risk model (see online supplemental table S2 for details on the variables used in this analysis). ICS, inhaled corticosteroids; OCS, oral corticosteroids.

Figure 2

Adjusted HRs of COVID-19 hospitalisation in children for different asthma status compared with children with no asthma. HRs of death COVID-19 hospitalisation compared with people with no asthma, obtained from Cox regression models. Sociodemographic factors include, region, ethnicity, quintile of the Index of Multiple Deprivation (see online supplemental table S2 for details on the variables used inthis analysis). OCS, oral corticosteroids.