COVID-19 severity and early inflammatory biomarkers in patients with immune-mediated inflammatory rheumatic diseases: a multicenter cohort study.

Patients with immune-mediated inflammatory rheumatic diseases (IMIRDs) may be more vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection because of underlying immune dysregulation. However, it remains unclear which factors determine coronavirus disease 2019 (COVID-19) severity in this population, especially in Eastern European settings. We conducted a retrospective, multicenter observational study including 211 patients with IMIRDs diagnosed with COVID-19 between 01.03.2020 and 31.12.2024. We collected clinical, demographic, and laboratory data within the first 72 hours of symptom onset and classified COVID-19 severity into three ordered categories. Associations with severity were examined using separate univariable ordinal logistic regression models and an additional multivariable model including age and IMIRD subtype. The main factors linked to more severe COVID-19 were older age (adjusted odds ratio [OR] 1.06; 95% confidence interval [CI]:1.03-1.09) and comorbidity burden (OR = 1.22; 95% CI, 1.12-1.31). Among patients with available laboratory measurements, higher levels of acute-phase reactants, as well as a higher derived neutrophil-to-lymphocyte ratio (dNLR) (OR = 1.30; 95% CI, 1.10-1.54) and lower monocyte counts (OR = 0.08; 95% CI, 0.02-0.36), remained associated with increased severity after Bonferroni correction for multiple comparisons. Accounting for age, patients with SLE had lower odds of greater COVID-19 severity than those with RA (OR = 0.35; 95% CI, 0.13-0.90). COVID-19 severity was associated with age, comorbidity burden, and early inflammatory response, with an age-adjusted difference also observed between SLE and RA. Routine inflammatory parameters and composite indices may contribute to early risk stratification in this population.