HRV Variation in Rheumatoid Arthritis

Inclusion Criteria: * Diagnosis of RA meeting 2010 ACR/EULAR classification criteria * Seropositive or seronegative RA eligible * Any baseline disease activity (remission/low/moderate/high) to minimize selection bias * Owns a compatible smartphone (iOS/Android) and is willing/able to use the Oura app * Willing to wear Oura Ring during sleep throughout study participation (target adherence ≥5 valid nights/week) * Willing to complete weekly remote assessments and attend baseline and three monthly routine follow-up visits * Able to read and write English language * Able to provide written informed consent Exclusion Criteria: * Atrial fibrillation or other clinically significant arrhythmias expected to invalidate HRV interpretation * Implanted pacemaker/defibrillator where HRV measurements are unreliable * Severe autonomic dysfunction likely to interfere with HRV interpretation (e.g., advanced diabetic autonomic neuropathy), per investigator judgment * Recent major cardiovascular event within 6 months (e.g., myocardial infarction) or uncontrolled heart failure (NYHA class III-IV), per investigator judgment * Current use of beta-blockers (excluded due to known autonomic/HRV effects) * Pregnancy or planned pregnancy during the study period * Inability to wear the ring reliably (e.g., occupational restrictions or hand deformity preventing wear) * Participation in another interventional clinical trial likely to confound outcomes