COVID-19 in rheumatoid arthritis: prevalence, hospital admission, and risk of all-cause mortality before and after COVID-19 pandemic.

Objectives: COVID-19 infection can trigger a cytokine storm, treatable with immunomodulating therapies similar to those used in rheumatoid arthritis (RA). This study investigated COVID-19 prevalence, hospitalisation, emergency department (ED) visits, and the impact of RA treatment and baseline characteristics on mortality in RA patients.

Methods: RA patients from the Ontario Best Practices Research Initiative (OBRI) were linked to Ontario healthcare records held at the Institute for Clinical Evaluative Sciences (ICES). The study examined COVID-19 infection, ED visits, hospitalisation, and intensive care unit (ICU) admissions between January 1st 2020, and March 31st 2022, and the risk of all-cause mortality before and after the pandemic.

Results: Among 2,969 RA patients, 596 (20.1%) had COVID-19. Of those with COVID-19, 108 (18.1%) were hospitalised or visited ED. Females were more likely to be infected (81.9% vs. 76.5%; adj ORs:1.30; 95% CI: 1.01-1.66). COVID-19 patients were more likely to use biologics (52.5% vs. 46.1%; adj ORs:1.28; 95% CI: 1.04-1.57) or Janus Kinase inhibitors (JAKi) (13.4% vs. 9.5%; adj ORs:1.44; 95% CI: 1.08-1.93). Older age (>80 years) (adj HR: 10.9; 95% CI:6.49-18.2), smoking (adj HR: 1.85; 95% CI:1.41-2.42), and higher disease activity score (adj HR: 1.09; 95% CI:1.00-1.18) were associated with higher all-cause mortality both before and after the COVID-19 pandemic, with stronger associations in the latter. JAKi were negatively associated with increased death before the pandemic (adj HR: 0.55; 95% CI: 0.34-0.91).

Conclusions: COVID-19 was higher in females, younger patients, those with comorbidities, and those using advanced therapies. Compared to pre-pandemic, higher death rates during the pandemic were associated with older age, oral steroid use, smoking, and higher disease activity.