Background To investigate factors associated with severe COVID-19 in people with rheumatic disease.

Methods Demographic data, clinical and laboratory characteristics and COVID-19 outcome severity of adults with rheumatic disease were collected from a single center in China from December 10, 2022 to January 31, 2023. A three-point ordinal COVID-19 severity scale was used to measure the severity of the disease. Multivariable ordinal logistic regression was used to estimate the odds ratios.

Results A total of 190 cases were included in the study. The most common rheumatic diseases were systemic lupus erythematosus (33.5%), rheumatoid arthritis (31.02%), Sjögren’s syndrome (10.7%), systemic sclerosis (6.42%), idiopathic inflammatory myopathy (5.88%), and vasculitis (8%). More than half of the cases (52.3%) were hospitalized, and 12 (6.3%) died. Over 60% of patients were on a stable stage of disease, and more than 18% were on biologics. Additionally, over 60% had not been vaccinated against COVID-19. The mortality rate for those without the COVID-19 vaccine is significantly higher than for those who have been vaccinated (9.5% vs.1.4%, P =0.03). Patients with pneumonia who died had significantly lower levels of lymphocytes than those who survived ( (0.45±0.07×

10^9/L vs. (0.99±0.12) ×10^9/L), P=0.01). Logistic regression analysis also revealed that older age, lymphopenia was associated with more severe COVID-19.

Conclusions Older age, low lymphocyte levels and no vaccination are risk factors for severe disease in COVID 19 in rhematic diseases.