ABSTRACT
Background: Nationwide data at a country level on Covid-19 in unvaccinated patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are scarce. Methods: By interlinking data from national electronic registries, covering nearly 99% of the Greek population (approximately 11,000,000), between March 2020 and February 2021, when vaccination became available, we recorded confirmed infections and Covid-19-associated hospitalizations and deaths in essentially all adult patients with RA, AS, PsA, SLE, and SSc under treatment (n=74,970, median age of 67.5, 51.2, 58.1, 56.2, 62.2 years, respectively) and in individually matched (1:5) on age, sex, and region of domicile random comparators from the general population. Results: Binary logistic regression analysis after adjusting for age, sex and biologic agents, revealed that RA, PsA, SLE and SSc, but not AS patients, had significantly higher risk of infection (by 43%, 25%, 20% and 49%, respectively), and hospitalization for Covid-19 (by 81%, 56%, 94%, and 111%, respectively), possibly due, at least in part, to increased testing and lower threshold for admission. Patients with RA and SSc had indeed higher Covid-19 associated mortality rates [OR:1.86 (95% CI 1.37 to 2.52) and OR:2.90 (95% CI 0.97 to 8.67), respectively] compared to the general population. Each additional year of age increased the risk of hospitalization for Covid-19 by 3% (OR 1.030, 95% CI: 1.028 to 1.034) and the risk of Covid-19 related death by 8% (OR 1.08, 95% CI: 1.07 to 1.09), independently of gender, systemic rheumatic disease, and biologic agents. A further analysis using AS patients as the reference category, adjusting again for age, sex and use of biologic agents showed that patients with SSc had increased mortality (OR: 6.90, 95% CI: 1.41 to 33.72), followed by SLE (OR: 4.05 95% CI: 0.96 to 17.12) and RA patients (OR: 3.65, 95% CI: 1.06 to 12.54), whereas PsA patients had comparable mortality risk with AS patients. Conclusion: Comparing to the general population, Covid-19 may have a more severe impact in real-world patients with systemic rheumatic disease. Covid-19 related mortality is increased in subgroups of patients with specific rheumatic diseases, especially in older ones, underscoring the need for priority vaccination policies and access to targeted treatments.