Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are chronic inflammatory rheumatic diseases characterised by pain, fatigue, mood disturbances, sleep problems and reduced quality of life. These symptoms are highly variable both between individuals and within individuals across days, reflecting the fluctuating nature of disease activity and daily functioning. Although physical activity is known to alleviate many of these symptoms, individuals with RA and SpA often encounter barriers that limit regular engagement. Capturing the dynamic interplay between symptoms and physical activity therefore requires methods that account for day-to-day and moment-to-moment variability. Ecological momentary assessment (EMA), especially when combined with actigraphy, enables real-time, context-sensitive monitoring of symptoms and physical activity in daily life. However, little is known about the feasibility and acceptability of such protocols in individuals with RA and SpA, for whom participant burden and adherence may represent significant challenges. This pilot study therefore aims to assess the feasibility and acceptability of a 14-day EMA protocol and to explore factors associated with objectively measured physical activity in individuals with RA and SpA.

50 adults diagnosed with RA or SpA will be recruited through rheumatology clinics or via advertisement. Eligible participants must be smartphone users without cognitive or physical impairments affecting participation. After providing consent, participants will complete baseline questionnaires regarding disease activity, quality of life, sleep, pain, fatigue, affective states and will attend a remote session with a member of the research team to learn how to use the mobile app. They will then complete a 14-day EMA protocol, during which data on patient-related outcomes (PROs), including pain, fatigue, sleep quality and affective states (i.e. positive and negative affects) will be assessed four times daily: upon awakening, 11:00, 15:00 and 20:30. Physical activity and sleep will be continuously monitored using both a wrist-worn and a thigh-worn device. Feasibility will be evaluated based on adherence to EMA prompts and actigraphy wear time. Acceptability will be assessed via a study-specific questionnaire and qualitative interviews conducted at the end of the protocol. Exploratory analyses will examine real-time, temporal and lagged relationships between PROs (pain, fatigue affective states), sleep and physical activity levels.

This study was approved by the French national ethics committee [Comité de protection des personnes Nord Ouest I, 2025-A01349-40] on 24/07/2025. The results will be disseminated in peer-reviewed journals and at international conferences.

NCT07167784.