Prevalence of COVID infections in a population of rheumatic patients from Lombardy and Marche treated with biological drugs or small molecules: A multicentre retrospective study.

Objective: The COVID-19 pandemic has raised questions about the management of systemic immunosuppressive treatments for rheumatic conditions. It is well known that rheumatic patients are at risk of developing infections because of their immunocompromised state. Moreover, drugs such as hydroxychloroquine or tocilizumab that are widely used to treat rheumatic diseases are now being used to treat COVID-19. The aim of this multicentre retrospective study of rheumatic patients in the Italian regions of Lombardy and Marche was to determine whether patients receiving biological or small molecules treatment are more susceptible to the development of COVID-19 than the general population.

Methods: The local registry data of 10,260 rheumatic patients being treated with bDMARDs or small molecules were evaluated from 15 March to 23 April 2020. The final analysis was based on the registry data relating to 7.204, telephone contacts and/or outpatient visits.

Results: Forty-seven of the 7.204 patients were diagnosed with COVID-19, seven of whom died; the patients who had symptoms resembling those of COVID-19 but had negative swabs were considered negative for the disease. The overall infection rate was 0.65, and the crude case fatality risk (CFR) in the patients with COVID-19 was 14.9%. There was no difference in the mortality rate among the patients receiving the different individual biological drugs or small molecules.

Conclusions: Our findings suggest that the susceptibility of rheumatic patients to COVID-19 is the same as that of the general population, but confirm that age, disease duration, and the number of co-morbidities are associated with an increased risk of a severe form of the disease. It seems that immunosuppressants drugs do not effectively represent a risk factor for COVID- 19.