Smartphone app aims to catch rheumatoid arthritis before it takes hold

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Must provide and sign the study's Informed Consent prior to any study-related procedures * Able to understand and interact with the study team * Agree to comply in good faith with all conditions of the recordings, and to attend all required study procedures. * Arthralgia (including hand joints PIP and or MCP) * Joint symptoms (arthralgia or stiffness) of recent onset (symptoms \<1 year) * Known positive ACPA-titer with written proof * Aged 18 years-old or more Exclusion Criteria: * Deformation of the hands or patients who have undergone joint arthrodesis or arthroplasty * Known microcrystal disease (e.g. gout, calcium pyrophosphate deposition) if hands are affected or pre-existing immune-mediated rheumatic diseases such as systemic lupus erythematosus or Sjögren's disease * Fulfilling the ACR/EULAR 2010 classification criteria for diagnosis of RA (≥ 6 points) * Known or suspected clinical synovitis by physician in \> 3 small joints (with or without involvement of large joints) * Any previous b, ts, and csDMARDs use * Lymphoedema in arms or hands following an axillary lymph node dissection * Inability to provide written informed consent * Severe cognitive impairment, severe psychiatric conditions or other inability to follow the procedures of the study * Immunosuppressive therapy for other autoimmune conditions \<2 years ago * Any Immunosuppressive therapy for other autoimmune conditions with B-cell depletion * Haematological or oncological treatments involving induction and / or maintenance chemotherapy within the last 5 years are not permitted * Participation in another investigation with an investigational drug or another MD within the 30 days preceding the trial or currently participating or planning to participate in an interventional trial * No regular (at least every 2 weeks) access to a smartphone * Adults who lack capacity to consent, known pregnant and breastfeeding women * Subjects for whom routine examination of the musculoskeletal system is not possible, or whose hands cannot be imaged (e.g., bandages that cannot be removed for hand picture taking, or injuries affecting the PIP joints both persisting for \> 49 days) * Enrolment of the PI, his/her family members, employees and other dependent persons