Background: Patients with obstructive lung diseases may be at risk of hospitalization and/or death due to COVID-19.
Aim: To estimate the frequency of severe COVID-19, and COVID-19-related mortality in a well-defined large population of patients with asthma and chronic inflammatory lung disease (COPD). Further to assess the frequency of asthma and COPD as registered comorbidities at discharge from hospital, and in death certificates.
Methods: At the start of the pandemic, the Swedish National Airway Register (SNAR) included 271,404 patients with a physician diagnosis of asthma and/or COPD. In September 2020, after the first COVID-19 wave in Sweden, the database was linked with the National Patient Register (NPR), the Swedish Intensive Care Register and the Swedish Cause of Death Register, which all provide data about COVID-19 based on International Classification of Diseases (ICD-10) codes. Severe COVID-19 was defined as hospitalization and/or intensive care or death due to COVID-19.
Results: Among patients in SNAR, 0.5% with asthma, and 1.2% with COPD were identified with severe COVID-19. Among patients < 18 years with asthma, only 0.02% were severely infected. Of hospitalized adults, 14% with asthma and 29% with COPD died. Further, of patients in SNAR, 56% with asthma and 81% with COPD were also registered in the NPR, while on death certificates the agreement was lower (asthma 24% and COPD 71%).
Conclusion: The frequency of severe COVID-19 in asthma and COPD was relative low. Mortality for those hospitalized was double as high in COPD compared to asthma. Comorbid asthma and COPD were not always identified among patients with severe COVID-19.
Keywords: COPD; COVID-19; asthma; death certificates; hospitalization; obstructive lung diseases; quality register; register studies.