COVID-19 hospitalizations, intensive care unit stays, ventilation and death among patients with immune mediated inflammatory diseases compared to controls

Objective — To investigate COVID-19 hospitalization risk in patients with immune mediated inflammatory diseases (IMIDs) compared with matched non-IMID comparators from the general population.

Methods — We conducted a population-based, matched cohort study using health administrative data from January to July 2020 in Ontario, Canada. Cohorts for each of the following IMIDs were assembled: rheumatoid arthritis (RA), psoriasis, psoriatic arthritis (PsA), ankylosing spondylitis, systemic autoimmune rheumatic diseases (SARDs), multiple sclerosis (MS), iritis, inflammatory bowel disease, polymyalgia rheumatica and vasculitis. Each patient was matched with 5 non-IMID comparators based on socio-demographic factors. We compared the cumulative incidence of hospitalizations for COVID-19 and their outcomes between IMID and non-IMID patients.

Results — A total of 493,499 IMID patients (417 hospitalizations) and 2,466,946 non-IMID comparators (1,519 hospitalizations) were assessed. The odds of being hospitalized for COVID- 19 was significantly higher in patients with IMIDs compared with their matched non-IMID comparators (matched unadjusted Odds Ratio (OR) 1.37, adjusted OR 1.23). Significantly higher risk of hospitalizations was found in patients with iritis (OR 1.46), MS (OR 1.83), PsA (OR 2.20), RA (OR 1.42), SARDs (OR 1.47) and vasculitis (OR 2.07). COVID-19 hospitalizations were associated with older age, male sex, long-term care residence, multimorbidity, and lower income. The odds of complicated hospitalizations was 21% higher among all IMID versus matched non-IMID patients, but this association was attenuated after adjusting for demographic factors and comorbidities.

Conclusion — Patients with IMIDs were at higher risk of being hospitalized with COVID-19. This risk was explained in part by their comorbidities.