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Unique COVID-19 studies in COPD and asthma patients

Published: 1 June 2022

In three studies including more than 270,000 persons in The Swedish National Airway Register (SNAR), diagnosed with asthma or Chronic obstructive pulmonary disease (COPD), researchers have investigated the association between severe covid-19 ( hospitalization or death due to covid-19 ) and asthma or COPD during the first wave of the pandemic. The results of all three studies are published and one of them was recently quoted in the highly ranked medical journal The Lancet.
The results were presented at Vetenskapens hus in Luleå.

The study now results in recommendations for both patients and healthcare.

"Our study shows how important it is, to contact health care if you have an uncontrolled asthma to get more intensive asthma treatment. It is also important to check your lung function at regular intervals. Preferably once a year for uncontrolled asthma and every three years in controlled asthma ", Caroline Stridsman says, Associate Professor, Department of Public Health and Clinical Medicine, Umeå University, Department of Respiratory Medicine, Sunderby Central Hospital of Norrbotten and Register Holder of the Swedish National Airway Register.

"Our results show the importance of identifying and treating people with uncontrolled asthma. In our studies we have seen an association between uncontrolled asthma and risk of severe COVID-19, Johanna Sundbaum says, Senior Lecturer in Medical Science at Luleå University of Technology and specialist in Respiratory Medicine.

Extensive registry studies

The covid-19 studies are based on patients with asthma and COPD patients in SNAR. Data was obtained from SNAR and by linkage to the National Patient Register , the Swedish Intensive Care Registry, the Swedish Cause of Death Register, the Prescribed Drug Register and The LISA-register. The studies have been performed  in collaboration between among others Region Norrbotten, Umeå University and Luleå University of Technology, The researchers behind the studies  Caroline Stridsman and Johanna Sundbaum have collaborated with several nurses and doctors in COPD and asthma care in whole Sweden.

What factors predict severe covid-19?

At an early stage in the covid-19 pandemic, an increased risk of severe covid-19 was reported in male and elderly patients and patients with underlying medical conditions as obesity, hypertension, diabetes, cardiovascular diseases and some lung diseases. In Sweden, in the first pandemic wave, patients with asthma and COPD were not classified as risk groups for severe covid-19, only if they had a very limited lung capacity.

Not everything was visible in the covid-19 statistics

At the first wave of pandemic there were few international or national published studies that specifically focused on asthma and COPD and risk of severe covid-19.

What factors predict severe covid-19 in asthma and COPD patients? This was the important issue in the studies performed by Johanna Sundbaum and Caroline Stridsman.The unique register data in Sweden enabled the studies.  By investigating different interesting factors from various registers, the researchers have been able to compare the patients seriously affected by covid-19 to all others in SNAR. Of interest have been lung function, treatment, need for inpatient care during 2019, smoking, educational level, and comorbidities.

Some of the results in the studies

Severe covid-19 was reported in  0.5 % of adults with asthma and 1.2 % of those with COPD in SNAR during the first wave of the pandemic. However, patients with COPD were slightly more affected than asthma patients, which may be due to the fact that those with COPD had a higher average age. Of patients being hospitalized due to COVID-19, 14 % of those with asthma and 29% of those with COPD died. These patient groups, as a whole, were not at a higher risk, to become severe ill in covid-19.

However, in regression analyses, uncontrolled asthma and COPD with higher symptom burden were associated with severe covid-19, and also for patients with a higher symptom burden in COPD.

The COPD study was published in a highly qualified scientific journal

 In COPD patients, lower lung function and more COPD related symptoms were associated with severe covid-19, a result published in highly ranked European and respiratory Journal..

"It is very important that patients with asthma and COPD with risk factors are identified, because they are the ones in these patient group who have the highest risk of becoming seriously affected by covid-19", Johanna Sundbaum says.

Funders of these studies are: Hjärt-Lungfonden, Asthma och Allergiförbundet, Riksförbundet HjärtLung, and Region Norrbotten, which is the research principal under the leadership of Caroline Stridsman. The lecture from Vetenskapens hus will soon be posted as a link on

Published scientific articles

Recording from the lecture

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