This study seeks to measure the psychometric properties of a newly developed Central Aspects of Pain in Rheumatoid Arthritis (CAP-RA) questionnaire, and investigate the ability of this questionnaire to measure central mechanisms of pain and also to predict worse pain and fatigue outcomes in people with Rheumatoid Arthritis (RA).

Persistent pain and fatigue are prevalent and disabling symptoms in people with Rheumatoid Arthritis, even in the absence of active inflammation. The investigators believe that these symptoms may be a result of abnormal pain processing by the Central Nervous System (CNS), in a process called central sensitization.

The investigators have developed a short, self-report questionnaire to measure central pain mechanisms in people with RA. It is called Central Aspects of Pain in Rheumatoid Arthritis (CAP-RA), and was adapted from a pre-existing questionnaire called CAP-Knee (which measures central sensitization in people with chronic knee pain).

This study aims to measure the psychometric properties of CAP-RA, and the ability of the questionnaire to predict worse pain in the RA population. Secondary objectives of the study include predicting worse fatigue in people with RA, deriving CAP-RA scoring recommendations, investigating other factors associated with persistent RA pain, the association between central sensitization and pain, and investigating the course of pain and fatigue in RA.

Participants will be recruited from a Rheumatology clinic. At baseline and 12 weeks these participants will undergo quantitative sensory testing (QST, pain tests), ultrasound for synovitis, clinical assessments, laboratory tests for systemic inflammation and, complete a questionnaire booklet, including the CAP-RA questionnaire.

Some participants will complete the CAP-RA questionnaire 1 week after the baseline visit to assess the test-retest reliability of the questionnaire.

In addition, participants will provide weekly pain and fatigue self-report via text message (SMS) for 12 weeks.

Inclusion Criteria:

• Adult (age≥18y) of any sex and ethnicity.
• Satisfy EULAR criteria for RA.
• Active RA, as defined as DAS28 ≥3.2 at baseline visit

Exclusion Criteria:

• Unable to give informed consent.
• Insufficient understanding of spoken or written English to comply with the requirements of the study protocol
• Unable or unlikely to complete the proposed 12-week study follow up (eg. moving house, terminal diagnosis, current or planned pregnancy).
• Active comorbidity (e.g. uncontrolled diabetes mellitus, cancer, infection) requiring changes in medical treatment at baseline
• Major active psychiatric condition (e.g. major depression)
• Inability to meet the requirements of clinical assessments

The study population will include people with Rheumatoid Arthritis receiving care at the Kings Mill Hospital, Sherwood Forest NHS Foundation Trust, Nottinghamshire, UK, who meet the eligibility criteria.

Pre-planned analyses will be performed by the study team. Requests for collaborative analyses of IPD, using non-identifiable data, may be made to the study PI.