Axial spondyloarthritis (axSpA) is a long-term inflammatory condition that affects the spine and sacroiliac joints. People living with axSpA often experience periods when their symptoms suddenly worsen, known as disease "flares." These flares can be painful, unpredictable, and significantly affect daily life, work and psychological wellbeing. Their unpredictable nature can leave people feeling helpless and anxious about when symptoms will return.

Research has shown that severe or frequent flares are linked to worse long-term outcomes in axSpA. However, it is difficult for researchers and clinicians to clearly define what a flare is, or to predict when one will happen. There is an unmet, urgent need to improve our understanding and recognition of flares, to enable earlier and more effective intervention, and improve long-term outcomes.

This study will explore people's experiences of flares, through a real-time digital flare and symptom diary. Data will be captured digitally from people living with axSpA over 12 months, including symptoms, diet, and lifestyle, self-management strategies and impact of flare on life, work, psychological wellbeing and relationships. Participants will attend clinic at two time points only (once when in flare, once when not in flare), to collect blood (serum) samples for investigation of inflammatory markers.

Findings will enable us to define and "map" different flare experiences of people living with axSpA and identify windows of opportunity for intervention and effective management. The results will inform the development of a novel, patient-initiated digital pathway for flare identification and management, which will be discussed and refined in a series of workshops with patients and healthcare professionals. This project will take place in two UK NHS hospitals (specialist rheumatology care settings): The Royal National Hospital for Rheumatic Diseases, Bath and King's College Hospital, London. We anticipate future work to pilot test the pathway and inform potential wider NHS implementation

Inclusion Criteria:

• Adult patients (≥18 years) with a diagnosis of axSpA (non-radiographic or radiographic axSpA).
• Access to an email address and electronic device, to participate in data collection.
• Capacity to provide informed consent.
• Sufficient communicative ability to participate in the research study (must be able to communicate in English).
• Patient has experienced at least one (self-reported) flare in the 12-months prior to enrolment.

Exclusion Criteria:

• Patients <18 years of age.
• Patients with another diagnosis of inflammatory arthritis that is not axial spondyloarthritis.
• Living with significant psychiatric morbidity, or if participation may cause distress.
• Patient has participated in Project Nightingale (RUH only, 2018 - 2022).

Patients with axSpA will be recruited from two study sites (RUH and KCH), whilst the RUH (Bath) patient population has limited ethnic and sociodemographic diversity. However, KCH (London) serves a more diverse population of patients.

Anonymised data may be shared with researchers in the future to carry out other research into axSpA. This is documented in the participant information sheets and consent forms and specific consent for future use is an option.