The burden of rheumatoid arthritis (RA) is profound, although treated with the treat-to-target strategy for RA patients according to the two most influential organisations for rheumatology worldwide. The need to timely achieve the control of disease activity for RA patients, especially for those difficult-to-treat individuals, is still unmet. Besides, the data on the diagnosis and prognosis of RA-related complications or comorbidities such as sarcopenia, cardiovascular diseases (CVD), malignancies and infections in large real-world cohorts are still limited. Therefore, the aim of this large-scale cohort study is to identify the development of clinical, biomedical, histopathological and imaging biomarkers for the diagnosis and prognosis of difficult-to-treat RA, and RA-related complications/comorbidities and to evaluate their impact on the prognosis of RA.

In this real-world multicentre prospective cohort, consecutive RA patients are planned to be recruited during 2024 and 2033 and with at least 5-year follow-up. Sociodemographic characteristics collection, clinical assessment, muscle assessment, histopathological assessment, imaging examination and biological samples collection will be performed at baseline, 1st, 3rd, 6th and 12th month during the first year and subsequently every 6 months until 5 years to repeat the assessments and collect the information of interested outcomes. The outcomes of interest include RA disease outcomes (including disease activity, functional and radiographic indicators) and RA-related complications/comorbidities (eg, sarcopenia, CVD, malignancies and specific infection).

Ethical approval has been approved by the Medical Ethics Committee of Sun Yat-sen Memorial Hospital, Sun Yat-sen University (ID: SYSKY-2023-1235-01); the Affiliated Panyu Central Hospital of Guangzhou Medical University (ID: PYRC-2024-214-01); and ShenShan Medical center, Memorial Hospital of Sun Yat-sen University (ID: 2024-SSKY-118-01). All study participants sign an informed consent form. Dissemination of results will occur via national and international conferences, in peer-reviewed journals, public conferences and social media.

NCT06233929.