Immune-Mediated Inflammatory Diseases like RA Linked to Severe COVID-19 Outcomes

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Age, chronic comorbidities, and COVID-19 vaccination status in patients with IMIDs serve as risk factors for severe COVID-19 outcomes.

A new study suggests although patients with immune-mediated inflammatory diseases (IMIDs) who have COVID-19 may have greater rates of hospitalization and mortality, factors such as age, chronic commodities, and COVID-19 vaccination status may have a greater influence on the COVID-19 outcome severity than IMIDs alone.1

“The results of our study suggest that, for patients with IMIDs, age, comorbidities, and not being fully vaccinated are more important predictive factors of severe COVID-19 outcomes than long-term use of [immunomodulatory medications],” wrote investigators, led by Qui Wei, PhD, from the Institute of Systems Biology in Seattle, and Phillip J. Mease, MD, from the Providence St Joseph Health-Swedish Medical Center in Seattle.

COVID-19 outcomes vary depending on the patient population, and since little was known about the outcomes in patients with IMIDs, the team decided to conduct a retrospective cohort study to assess the severe COVID-19 outcomes in patients with IMIDs. They also sought to see how the severe outcome risk was associated with classes of immunomodulatory medications, chronic comorbidities, and COVID-19 vaccination status. Already, previous research found rheumatoid arthritis was a risk factor for the COVID-19 outcomes of hospitalization and death.2

Investigators leveraged data from Providence St. Joseph Health, a healthcare system treating patients in 51 hospitals and 1085 clinics throughout 7 US states.1 The sample included patients with and without IMIDs, and there was no age restriction. A positive nucleic acid implication test for SARS-CoV-2 indicated a patient had COVID-19.

The team analyzed data from the pre-omicron period (March 1, 2020 – December 25, 202) and the omicron-predominant period (December 26, 2021 – August 30, 2022). Primary outcomes included hospitalization, mechanical ventilation, and mortality in patients with COVID-19.

The sample included 290,855 patients with COVID-19, 15,397 patients with IMIDs, and 275,458 without IMIDs. In the pre-omicron period, 169,993 patients in the sample tested positive for COVID-19, and of these patients, 13.7% were hospitalized, 0.6% received mechanical ventilation, and 3.1% died. Compared with controls, patients with IMIDs and COVID-19 had greater rates of hospitalization (14.6% vs 13.7%; P = .024) and mortality (3.9% vs 3.1%; P < .0001).

In the omicron-predominant period, 120,662 patients tested positive for COVID-19, and of them, 12% were hospitalized, 0.5% received mechanical ventilation, and 1.7% died. Patients with IMIDs and COVID-19 had greater rates of hospitalization (14.8% vs 11.8%; P < .0001) and mortality (2.6% vs 1.6%; P < .0001) than controls.

Age was a risk factor for worse outcomes (from adjusted odds ratio [aOR], 2.1; 95% confidence interval [CI], 2.0 – 2.1; P < .0001 to 3.0; 95% CI, 2.9 – 3.0). However, a COVID-19 vaccination (from 0.082; 95% CI, 0.080 – 0.085; P < .0001 to 0.52; 95% CI, 0.50 – 0.53; P < .0001) and a booster vaccination (from 2.1; 95% CI, 2.0 – 2.2; P < .0001 to 3.0; 95% CI, 2.9 – 3.0) status were linked to better outcomes.

The chronic comorbidities of atrial fibrillation, coronary artery disease, heart failure, chronic kidney disease, chronic obstructive pulmonary disease, chronic liver disease, and cancer served as significant risk factors for all 3 outcomes. In contrast, asthma (aOR from 0.33; 95% CI, 0.32 – 0.34; P < .0001 to 0.49; 95% CI, 0.48 – 0.51; P < .0001), psoriasis (from 0.52; 95% CI, 0.48 – 0.56 to 0.80; 95% CI, 0.74 – 0.87; P < .0001) in both periods, and spondylarthritis during the pre-omicron period reduced the risk of all 3 COVID-19 outcomes.

The study had several limitations, including insufficient data on IMID severity, non-IMID comorbidities, and SARS-CoV-2 immunity, as well as missing information on COVID-19 patients not tested at PSJH. It also failed to account for variations in medication dosing, timing, and duration 3 months before the infection, and the increased use of at-home rapid tests during the omicron period may have led to underreporting of severe outcomes. Additionally, potential confounders like behavioral choices, other medications, economic exposures, delays in care, and selection bias from only including PSJH patients may have affected the results.

“Overall, there is a need to take age and comorbidities into consideration when developing COVID-19 guidelines for patients with IMIDs,” investigators wrote. “Further research is needed for specific IMIDs (including IMID severity at the time of SARS-CoV-2 infection) and IMMs (considering dosage and timing before a patient's first COVID-19 infection).”


  1. Wei Q, Mease PJ, Chiorean M, et al. Machine learning to understand risks for severe COVID-19 outcomes: a retrospective cohort study of immune-mediated inflammatory diseases, immunomodulatory medications, and comorbidities in a large US health-care system. Lancet Digit Health. 2024;6(5):e309-e322. doi:10.1016/S2589-7500(24)00021-9
  2. Bournia VK, Fragoulis GE, Mitrou P, et al. Outcomes of COVID-19 Omicron variant in patients with rheumatoid arthritis: a nationwide Greek cohort study. Rheumatology (Oxford). 2024;63(4):1130-1138. doi:10.1093/rheumatology/kead354