This is a summary, written by members of the CITF Secretariat, of:

Eder L, Croxford R, Drucker AM, Mendel A, Kuriya B, Touma Z, Johnson SR, Cook R, Bernatsky S, Haroon N, Widdifield J. Understanding COVID-19 Risk in Patients with Immune Mediated Inflammatory Diseases: A Population-based analysis of SARS-CoV-2 Testing. Arthritis Care Res. 6 Sep 2021 . doi: 10.1002/acr.24781.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A study by researchers at the University of Toronto, in collaboration with CITF-funded researcher Dr. Sasha Bernatsky from the Research Institute of the McGill University Health Centre, observed that people with autoimmune diseases had the same proportion of SARS-CoV-2 positive tests and a similar disease incidence compared to the general population in 2020. However, testing for COVID-19 is higher than in the general population. Their results are published in Arthritis Care & Research.

In this Ontario-based study, researchers compared the rates of SARS-CoV-2 testing among people with autoimmune or immune-mediated inflammatory diseases (IMID) to people in the general population. Information on SARS-CoV-2 testing, as well as test results, was captured from January 1, 2020, to December 17, 2020. A total of 493,499 patients with IMIDs and 2,466,946 patients without an IMID were included in this study.

Key points:

  • The same proportion of patients with and without IMIDs tested positive for COVID-19 (0.9%) or (90.8 vs 90 per 10,000 population).
  • Testing rates were significantly higher for IMID patients (20% higher odds) compared to patients without an IMID: during the study period, 27.4% of patients with IMIDs were tested for SARS-COV-2, compared to 23.4% of patients without IMIDs. Factors found to be associated with testing included: living in a long-term care facility, being female, of younger age, and having more than one diagnosis.
  • When looking at specific diseases, rheumatoid arthritis and iritis did show a higher risk of infection when compared to the general population. Other risk factors for testing positive for SARS-CoV-2 among IMID patients included: living in a long-term care facility, multiple medical diagnoses, lower socioeconomic status, residing in the city, and younger age.

Overall, this study provides information on pre-vaccination rates of SARS-CoV-2 infection among people with IMIDs, as well as identifying risk factors of COVID-19 infection.

Click here to find out more about Dr. Bernatsky’s CITF-funded study on assessing the impact of vaccines on people with IMID.