Fewer than normal patients presented with severe asthma attacks, or were hospitalised with pneumonia, influenza and chronic lung diseases during the first phase of the COVID-19 pandemic, according to three new studies.
Researchers believe the impact of reduced rates of infection and shielding may have helped protect patients with asthma.
Two of the papers, published online in Thorax, examine data from Great Britain, while the third looks at cases in South Korea.
In the first paper, Dr Syed Shah from the Asthma UK Centre for Applied Research at The University of Edinburgh and colleagues used the Optimum Patient Care Database of 9,949,387 patients in England to assess weekly asthma exacerbation rates between January and August 2020 and compared them with figures from the same period in 2019.
After 23 March 2020, when the UK went into the first lockdown, there were almost 20 fewer episodes for every 100 patients with asthma and the reduction was only significant for patients who did not attend hospital or require hospital admission.
Dr Shah said: “We believe that a combination of factors led to a reduction in asthma exacerbations. These factors include changing behaviour due to lockdown measures leading to reduction in air pollution, reduced circulation of respiratory viruses, improved self-management driven by patient concerns during the pandemic and shielding by a subset of patients.”
In the second paper, Professor Gwyneth Davies, of Swansea University Medical School, and colleagues examined official data on emergency admissions and deaths due to asthma from Scotland’s Public Health Scotland and Wales’ SAIL databank.
They compared weekly rates in the first 18 weeks of 2020 with the national averages over 2015-2019 and investigated how trends changed between the first 13 weeks of 2020 compared with the five weeks post-lockdown.
Across both countries, the number of asthma exacerbations resulting in emergency hospital admission fell by 36% post lockdown, and there was no significant change in asthma deaths.
Prof Davies said: “We do not yet know to what degree the reduced numbers of emergency presentations of asthma in our study are due to improvements in asthma control or reductions in exposures to triggers during the pandemic versus avoidance of healthcare settings.”
The study notes in Wales there was a large spike in GP prescriptions for asthma medication the week before lockdown – 121% more inhaled corticosteroids and 133% more oral corticosteroid prescriptions compared with the five-year average.
In the third paper, Dr Jaehun Jung from Gachon University Gil Medical Centre, South Korea, and collaborators report that the COVID-19 pandemic was associated with a fall in hospital admissions for pneumonia, influenza, chronic obstructive pulmonary disease (COPD) and asthma in South Korea.
Looking at figures from the National Health Insurance Service for January 2016-January 2020 as a baseline, they examined weekly hospitalisation between February and July 2020.
“Since the early days of the COVID-19 epidemic, South Korea has thoroughly carried out social distancing, personal hygiene and universal use of face masks. In this study, the significant decrease in hospital admissions for influenza, pneumonia, COPD and asthma suggests the unintended benefits of these measures,” said Dr Jung.
“Our findings suggest that the decrease in admissions due to COPD and asthma might be associated with the decrease in respiratory infections, which are the most common triggers for acute exacerbation of COPD and asthma.”
The authors of all three papers add that because these are observational studies, they cannot establish cause and point to some limitations.
Shah SA, Quint JK, Nwaru BI et al. Impact of COVID-19 national lockdown on asthma exacerbations: interrupted time-series analysis of English primary care data. Thorax 30 March 2021; doi:10.1136/thoraxjnl-2020-216512
Davies GA, Alsallakh MA, Sivakumaran S et al. Impact of COVID-19 lockdown on emergency asthma admissions and deaths: national interrupted time series analyses for Scotland and Wales. Thorax 30 March 2021; doi:10.1136/thoraxjnl-2020-216380
Huh K, Kim YE, Ji W et al. Decrease in hospital admissions for respiratory diseases during the COVID-19 pandemic: a nationwide claims study. Thorax 30 March 2021; doi:10.1136/thoraxjnl-2020-216526
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