Advanced Sensor Based Functional ASsessmenTs in Axial Spondyloarthritis

An Investigation Into the Responsiveness of Inertial Measurement Unit (IMU) Sensor-based Tests in Measuring Changes in Spinal Mobility and Function in Axial Spondyloarthritis Patients Treated With Biologic Drug

This is an observational study using Inertial Measurement Unit (IMU) sensors to measure the effects of biological therapy on spinal mobility and function in axial spondyloarthritis. Participants will undergo MRI scans before and after therapy in parallel to the sensor tests to establish correlation between changes in inflammatory signs and changes in spinal mobility.

We will study 20 participants with active axial spondyloarthritis (axSpA) who are about to start biologic therapy as part of routine care. In brief, we will carry out the following assessments before and after therapy:

1. MRI of spine and Sacroiliac (SI) joints - modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) scoring
2. Record standard Patient recorded outcomes (PROs): Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Global (BASG), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Disease Activity Score (ASDAS), Ankylosing Spondylitis Disease Activity Score Health Index (ASAS-HI), Euroquol 3 level health assessment (EQ5D-3L), work productivity and activity impairment questionnaire (WPAI), Short QUestionnaire to ASsess Health enhancing physical activity (SQUASH),
3. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)
4. IMU sensor tests in clinic for range of motion (ROM) in cervical, thoracic and lumbar spine.
5. IMU sensor tests at home for standardised function testing

Inclusion Criteria:

1. Diagnosis of axial spondyloarthritis fulfilling ASAS classification criteria.
2. Age ≥18 years old and <80 years.
3. Fulfilment of local criteria for biologic therapy for axSpA.
4. The subjects should be able to read, write, understand and complete study questionnaires.
5. Each subject must sign an informed consent form (ICF) indicating that he or she understands the purpose of and procedures required for the study and are willing to participate in the study.

Exclusion Criteria:

1. Safety contra-indication for biologic drug therapy.
2. Severely restricted hip movement (less than 20 degrees rotation in either hip).
3. History of previous clinical (symptomatic) vertebral fracture.
4. History of previous spinal surgery.
5. History of previous hip replacement surgery.
6. Major scoliosis deformity (in the opinion of the investigator).
7. Safety contra-indication for MRI assessment.
8. Previous biologic agent within 2 months.
9. Pregnant or breast-feeding women.