People with an inflammatory rheumatic disease have similar risk of getting COVID to those without rheumatic disease, but a higher chance of poor infection outcomes.
Introduction
COVID-19 is the disease caused by a virus called severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It was declared a pandemic by the World Health Organization on 11 March 2020.
Some people with inflammatory rheumatic diseases are more likely to get infections. Inflammatory rheumatic diseases are a group, which includes rheumatoid arthritis, psoriatic arthritis, spondyloarthropathies, lupus erythematosus, ANCA-associated vasculitis (AAV), systemic scleroderma, giant cell arteritis, and Sjøgren’s disease. Some people with one of these conditions are also more likely to suffer complications when they get an infection. This is partly because of their underlying disease, and partly because some medicines used to treat rheumatic diseases work by suppressing the immune system.
What did the authors hope to find?
The authors wanted to find out more about COVID infections in people with inflammatory rheumatic diseases compared to people in the general population, and to see how this changed in different periods of the pandemic, such as later on when the most common strain was Omicron. Most other scientific papers on this topic were published in the first year of the pandemic. But there is not as much information about the consequences for people with an inflammatory rheumatic disease during later periods. They also wanted to look at the impact of the second and third COVID vaccinations.
Who was studied?
The study looked at 66,840 adults. Everyone had an inflammatory rheumatic disease, and was living in Denmark. A group of 666,840 people of the same age and sex from the general population was used as a comparison (the control group).
How was the study conducted?
This was an observational, nationwide, population-based study. This means that the authors looked at data on a set of patients, but made no interventions and there was no medicine under investigation.
The authors used databases in Denmark to get information on people’s sex, date of birth, as well as their immigration and emigration status. Results of COVID PCR and antigen tests were obtained from the national system, which collects data from all COVID tests done in public facilities such as hospitals, as well as private testing facilities. Information about people’s COVID vaccination status was collected from the Danish vaccination register. Finally, the authors got information from medical health records about people’s diagnosis and the severity of their COVID infection.
The researchers then used all this information to compare COVID infection in people with and without an inflammatory rheumatic disease. This included people’s risk of being hospitalised due to severe COVID, their need for assisted ventilation to help them breathe, and their risk of dying from COVID.
What were the main findings?
The main finding was that one-third of vaccinations were associated with a reduced risk of being hospitalised for COVID. Vaccination also reduced the risk of death in both groups.
From March 2020 to January 2023, people with an inflammatory rheumatic disease had a similar risk of catching COVID compared to the general population. However, compared to the general population, they had a substantial risk of needing to go into hospital because of severe COVID, and were more likely to need assisted ventilation, or to die from COVID.
The risk of hospitalisation after the first COVID infection in the Omicron period was increased in people with an inflammatory rheumatic disease compared to the control group. The risk of death dropped substantially after the Omicron variant became the main strain causing infections. However, the risk of death after the first positive test in the Omicron period was higher for people with AAV or rheumatoid arthritis compared to the control group.
Are these findings new?
This is the largest nationwide study of people with an inflammatory rheumatic disease compared to a control group from the general population. It investigated the impact of the pandemic, looked at long-term outcomes from the vaccination program, and evaluated the testing strategy. In Denmark there was a policy for free COVID testing, even in people who did not have any symptoms. Some people felt this was excessive, but it has provided researchers with the unique possibility of minimising underreporting of COVID infections.
What are the limitations of this study?
One limitation is that it possible the rheumatic disease and COVID diagnoses was wrong in the databases. This would mean an underestimation of the COVID effects in people with an inflammatory rheumatic disease. However, previous studies have shown a high predictive value of diagnoses in the database that was used to get people’s rheumatic disease information. Other limitations include lack of access to information about what medicines people were taking. Differences in behavioural change could also have affected the results, since people with an inflammatory rheumatic disease may have taken greater steps to protect themselves from infection than people in the general population.
What do the authors plan on doing with this information?
The results from this study have been presented at national and international congresses, in the hope they will make rheumatologists more aware of high-risk patients in their daily clinical practice. In addition, the authors are planning further studies.
What does this mean for me?
If you have an inflammatory rheumatic disease, you are more likely to get infections than other people. These findings suggest that your risk of COVID is almost the same as someone in the general population. However, you could be more at risk of poor outcomes, such as being admitted to hospital, or needing ventilation to help you breathe. Your individual risks will depend on your particular disease, and your general health. Patients with an inflammatory rheumatic disease are advised to follow vaccination programs and to maintain good hygiene in order to avoid infection.
If you have any concerns about your disease or its treatment, you should talk to a healthcare professional involved in your care.
Date prepared: June 2024
Summary based on research article published on: January 2023
From: Summary from Svensson ALL, et al. Outcomes following SARS-CoV-2 infection in individuals with and without inflammatory rheumatic diseases: a Danish nationwide cohort study. Ann Rheum Dis 2023;82:1359–67. doi:10.1136/ard-2023-223974
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