Clinical outcomes of hospitalised patients with COVID-19 and chronic inflammatory and autoimmune rheumatic diseases: a multicentric matched cohort study

Objectives The impact of inflammatory rheumatic diseases on COVID-19 severity is poorly known. Here, we compare the outcomes of a cohort of patients with rheumatic diseases with a matched control cohort to identify potential risk factors for severe illness. Methods In this comparative cohort study, we identified hospital PCR+COVID-19 rheumatic patients with chronic inflammatory arthritis (IA) or connective tissue diseases (CTDs). Non-rheumatic controls were randomly sampled 1:1 and matched by age, sex and PCR date. The main outcome was severe COVID-19, defined as death, invasive ventilation, intensive care unit admission or serious complications. We assessed the association between the outcome and the potential prognostic variables, adjusted by COVID-19 treatment, using logistic regression. Results The cohorts were composed of 456 rheumatic and non-rheumatic patients, in equal numbers. Mean age was 63 (IQR 53-78) years and male sex 41% in both cohorts. Rheumatic diseases were IA (60%) and CTD (40%). Most patients (74%) had been hospitalised, and the risk of severe COVID-19 was 31.6% in the rheumatic and 28.1% in the non-rheumatic cohort. Ageing, male sex and previous comorbidity (obesity, diabetes, hypertension, cardiovascular or lung disease) increased the risk in the rheumatic cohort by bivariate analysis. In logistic regression analysis, independent factors associated with severe COVID-19 were increased age (OR 4.83; 95% CI 2.78 to 8.36), male sex (1.93; CI 1.21 to 3.07) and having a CTD (OR 1.82; CI 1.00 to 3.30). Conclusion In hospitalised patients with chronic inflammatory rheumatic diseases, having a CTD but not IA nor previous immunosuppressive therapies was associated with severe COVID-19. Key messages What is already known about this subject? ► There is limited evidence on the outcomes of COVID-19 in patients with rheumatic diseases and the impact of age, comorbidity, therapy or other factors associated to severity specifically in these patients. What does this study add? ► We found that severe COVID-19 occurred in 31.6% of the rheumatic and 28.1% of nonrheumatic cohorts. ► Having a connective tissue disease but not its therapy was significantly associated with severe COVID-19. ► Other known risk factors as ageing or male sex also apply to patients with rheumatic diseases. How might this impact on clinical practice or future developments? ► These findings have important implications to guide COVID-19 recommendations to specific groups of patients with rheumatic diseases and to provide evidence-based advice on the importance of maintaining therapies.