Today, regular X-ray examination is not sufficiently sensitive for detecting progression of bone destruction in rheumatoid arthritis, but a new type of high-resolution CT scanner, the High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) can detect very early and minor joint injuries.

The purpose of this study is to use HR-pQCT techniques to look at the damage and disease activity progression in the hand and wrist joints of patients with rheumatoid arthritis.

The design of the trial is an observational study with three distinct groups. At the start of the trial period and at one-year of follow-up, the trial subject will have their hand X-rayed by conventional radiography, and their metacarpophalangeal (MCP) joint and wrist scanned by HR-pQCT-Imaging. The 28-joint Disease Activity Score(DAS28-CRP), Health Assessment Questionnaire (HAQ), Visual analogue scale(VAS)-score for pain, fatigue and quality of life are performed to investigate the correlation between radiographic changes and disease activity. Blood samples are collected to investigate serological markers of bone metabolism and inflammation and the radiographic changes. The following groups are investigated:

• Rheumatoid Arthritis(RA): Patients with RA ≥5 years according to the ACR/EULAR 2010 classification criteria or the American Rheumatism Association 1987 revised criteria are recruited from the outpatient clinic at the Department of Rheumatology, Aarhus University Hospital. Treatment will be adjusted according to the patient's need and according to national guidelines. (n=450)
• Pre-RA patients: Patients with pre-RA, (joint pain, but no swelling and Anti-CCP 3 times above the upper limit) are recruited from the outpatient clinic at the Department of Rheumatology, Aarhus University Hospital. (n=75)
• Healthy subjects: Healthy age- and sex-matched Individuals are recruited, as a control group, by posting at libraries in Aarhus, Aarhus University, Aarhus University Hospital and postings on the websites www.forsøgsperson.dk and www.Sundhed.dk. (N=100)

Rheumatoid arthritis patients Inclusion criteria

• Patients (> 18 years) with rheumatoid arthritis ≥5 years according to the ACR/EULAR (2010) classification criteria or American Rheumatism Association 1987 revised criteria for the patients who were diagnosed before 2010.
• Patients who are receiving treatment on an outpatient basis.
• Ability and willingness to give written informed consent and to meet the requirements of the trial protocol.

Exclusion criteria

• Patients who have previously suffered trauma in the form of fracture or luxation of the hand are excluded.
• Evidence of active malignant disease.
• Hypo- or hyperthyroidism.
• Hypocalcaemia.
• Impaired renal function (eGFR <35ml/min).
• Pregnancy. Pre-rheumatoid arthritis patients Inclusion criteria
• Age over 18 years.
• Anti-CCP 3 times the upper limit of the reference interval.
• Arthralgia.
• Ability and willingness to give written informed consent and to meet the requirements of the trial protocol.

Exclusion criteria

• Pregnancy.
• Swelling of joints. Verified by clinical ultrasound.
• Patients who have previously suffered trauma in the form of fracture or luxation of the hand are excluded.
• Evidence of malignant disease.
• Hypo- or hyperthyroidism.
• Hypocalcaemia. Healthy subjects Inclusion criteria
• Age over 18 years.
• No joint complaints.
• Ability and willingness to give written informed consent and to meet the requirements of the trial protocol.

Exclusion criteria

• Patients who have previously suffered trauma in the form of fracture or luxation of the hand are excluded.
• Evidence of malignant disease.
• Hypo- or hyperthyroidism.
• Hypocalcaemia.
• Impaired renal function (eGFR <35ml/min).
• Earlier or present rheumatological disease or bone metabolic disease.
• Positive anti-CCP.
• Pregnancy.

Rheumatoid arthritis patients and pre-rheumatoid patients are recruited from the outpatient clinic at the Department of Rheumatology, Aarhus University Hospital.

Healthy age- and sex-matched Individuals are recruited, as a control group, by posting at libraries in Aarhus, Aarhus University, Aarhus University Hospital and postings on the websites www.forsøgsperson.dk and www.Sundhed.dk.