Prognostic Improvement and Treatment of COVID-19 in Patients with Rheumatic Diseases until December 2022: Analysis of the JCR COVID-19 Registry in Japan

Objectives The aim is to evaluate the treatment and prognosis of coronavirus disease 2019 (COVID-19) according to the time of onset and dominant strain in patients with rheumatic diseases. Methods This study analysed a nationwide COVID-19 registry of Japanese patients with rheumatic diseases compiled between June 2020 and December 2022. The primary endpoints of the study were hypoxaemia incidence and mortality. Multivariate logistic regression analysis was performed to assess differences according to the period of onset. Results A total of 760 patients were compared across four periods. Hypoxaemia rates were 34.9, 27.2, 13.8, and 6.1% and mortality rates were 5.6, 3.5, 1.8, and 0% until June 2021, between July and December 2021, January and June 2022, and July and December 2022, respectively. History of vaccination (odds ratio, 0.39; 95% confidence interval, 0.18-0.84) and onset during the July to December 2022 Omicron BA.5-dominant period (odds ratio, 0.17; 95% confidence interval, 0.07-0.41) were negatively associated with hypoxaemia in the multivariate model, adjusting for age, sex, obesity, glucocorticoid dose, and comorbidities. Over the Omicron-dominant period, antiviral treatment was administered in 30.5% of patients with a low probability of hypoxaemia. Conclusions COVID-19 prognosis improved over time in patients with rheumatic diseases, especially in the Omicron BA.5-dominant period. In the future, treatment of mild cases should be optimised.