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.