This is a multi-center, prospective, real-world observational study. Patients who have completed 6 months of induction therapy (YISAIPU 50mg / week ± csDMARDs) and achieved clinical remission or low disease activity will be observed for 2.5 years. During the maintenance period, through full communication between doctors and patients, YISAIPU 50 mg/wk or YISAIPU 25 mg/wk will be chosen as maintenance treatment. The clinical efficacy evaluation parameters include DAS28, HAQ-DI, modified Sharp score, continuous medication rate, and the recurrence rate of rheumatoid arthritis. Drug safety evaluation will include the incidence of adverse drug reactions and adverse drug events, the incidence of serious adverse events, and the incidence of adverse events leading to the reduction or withdrawal of YISAIPU due to adverse events. Exploratory observations wil include: (1) the incidence, clinical characteristics and disease changes of Interstitial Lung Disease, (2) the baseline abnormal rate and 3-year change of carotid intima-media thickness.
