<p>Existing Data Sources in Clinical Epidemiology: The Danish COVID-19 Cohort</p>

Abstract

Background: To facilitate research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a prospective cohort of all Danish residents tested for SARS-CoV-2 in Denmark is established. Data Structure: All Danish residents tested by reverse transcriptase polymerase chain reactions (RT-PCR) for SARS-CoV-2 in Denmark are included. The cohort is identified using the Danish Microbiology Database. Individual-level record linkage between administrative and health-care registries is facilitated by the Danish Civil Registration System. Information on outcomes related to SARS-CoV-2 infection includes hospital admission, intensive care unit admission, mechanical ventilation, and death and is retrieved from the five administrative Danish regions, the Danish National Patient Registry, and the Danish Register of Causes of Death. The Patient Registry further provides a complete hospital contact history of somatic and psychiatric conditions and procedures. Data on all prescriptions filled at community pharmacies are available from the Danish National Prescription Registry. Health-care authorization status is obtained from the Danish Register of Healthcare Professionals. Finally, selected laboratory values are obtained from the Register of Laboratory Results for Research. The cohort is governed by a steering committee with representatives from the Danish Medicines Agency, Statens Serum Institut, the Danish Health Authority, the Danish Health Data Authority, Danish Patients, the Faculties of Health Sciences at the Danish universities, and Danish regions. The steering committee welcomes suggestions for research studies and collaborations. Research proposals will be prioritized based on timeliness and potential clinical and public health implications. All research protocols assessing specific hypotheses for medicines will be made publicly available using the European Union electronic Register of Post-Authorisation Studies. Conclusion: The Danish COVID-19 cohort includes all Danish residents with an RT-PCR test for SARS-CoV-2. Through individual-level linkage with existing Danish health and administrative registries, this is a valuable data source for epidemiological research on SARS-CoV-2.

Post-acute effects of SARS-CoV-2 infection in individuals not requiring hospital admission: a Danish population-based cohort study

“…This Danish population-based cohort study used the Danish national health registries and the Danish COVID-19 cohort. 13 We examined incident drug use, hospital diagnoses, and overall health-care use extending from 2 weeks to 6 months after a positive SARS-CoV-2 test in individuals who did not require hospital admission. For initiation of drugs and first hospital diagnoses representing potential late complications of SARS-CoV-2 infection, we obtained risks, risk differences, and risk ratios compared with individuals who tested negative for SARS-CoV-2.…”

“…From April 21, testing of individuals with mild symptoms and asymptomatic contacts was gradually introduced and on May 18, testing for SARS-CoV-2 was made available for anyone free of charge. 13 …”

Inhaled corticosteroid use in COVID-19

“…The Danish Civil Registration System (CRS) allows individual-level linkage of information from national health registers, in addition to providing demographic information on the Danish population(9). Information on PCR tests for SARS-CoV-2 and influenza infection is available through MiBA, the Danish Microbiology Database, which includes all microbiological test results in Denmark, starting from 2010(10–12). The Danish National Patient Register covers information on hospital admission, admission to intensive care units (ICU), use of mechanical ventilation, and diagnostic codes to identify underlying comorbidities(13).…”

Adverse Outcomes and Mortality in Users of Non-Steroidal Anti-Inflammatory Drugs tested positive for SARS-CoV-2: A Danish Nationwide Cohort Study

“…Data on all Danish residents with a positive test for SARS-CoV-2 were obtained from Danish health and administrative registries as described elsewhere (11). In brief, identification of the study population was based on prospectively collected data on all Danish residents receiving a polymerase chain reaction (PCR)-test for SARS-CoV-2 from the Danish Microbiology Database (12).…”