Hospital admissions in inflammatory rheumatic diseases during the COVID-19 pandemic: incidence and role of disease modifying agents

Background: In this pandemia, it is essential for rheumatologist and patients to know the relationship between COVID-19 and inflammatory rheumatic diseases (IRD). We want to assess the role of targeted synthetic or biologic disease modifying antirheumatic drugs (ts/bDMARDs) and other variables in the development of moderate-severe COVID-19 disease in IRD. Methods: An observational longitudinal study was conducted (1stMar to 15thApr 2020). All patients from the rheumatology outpatient clinic from a hospital in Madrid with a medical diagnosis of IRD were included. Main outcome: hospital admission related to COVID-19. Independent variable: ts/bDMARDs. Covariates: sociodemographic, comorbidities, type of IRD diagnosis, glucocorticoids, NSAIDs and conventional synthetic DMARDs (csDMARDs). Incidence rate (IR) of hospital admission related to COVID-19, was expressed per 1,000 patients-month. Cox multivariate regression analysis was run to examine the influence of ts/bDMARDs and other covariates on IR. Results: 3,591 IRD patients were included (5,896 patients-month). Concerning csDMARDs, methotrexate was the most used followed by antimalarials. 802 patients were on ts/bDMARDs, mainly anti-TNF agents, and rituximab. Hospital admissions related to COVID-19 occurred in 54 patients (1.36%) with an IR of 9.15 [95%CI: 7-11.9]. In the multivariate analysis, older, male gender, presence of comorbidities and specific systemic autoimmune conditions (Sjoegren, polychondritis, Raynaud and mixed connective tissue disease) had more risk of hospital admissions regardless other factors. Exposition to ts/bDMARDs did not achieve statistical signification. Use of glucocorticoids, NSAIDs, and csDMARDs dropped from the final model. Conclusion: This study provides additional evidence in IRD patients regarding susceptibility to moderate-severe infection related to COVID-19.