Protocol for the Feasibility Study of INSPIRE: an Individually Tailored Support Intervention for Informal Caregivers of Older Adults With Rheumatoid Arthritis and Frailty

Background Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with pain, fatigue, functional limitations, and reduced quality of life. As more people live to older age with RA, age-related vulnerability such as frailty becomes increasingly relevant and may amplify functional decline, multimorbidity, and reliance on others. Informal caregivers (unpaid family members, friends, or neighbors) often provide substantial practical, emotional, and coordination support, yet caregiver needs are frequently overlooked in rheumatology care. INSPIRE (INtervention to Support Partners and Informal caREgivers of frail RA patients) is an individually tailored support intervention developed using the UK Medical Research Council framework for complex interventions and an iterative co-creation process involving older adults with RA and frailty, caregivers, healthcare professionals, and social care stakeholders. Before a definitive evaluation, feasibility and acceptability in routine care must be established.

Aim To evaluate the feasibility and acceptability of delivering INSPIRE in routine rheumatology care and to test study procedures in preparation for a future definitive trial.

Methods This is a single-arm feasibility study recruiting 25 informal caregivers of older adults with RA and frailty. Recruitment will occur within a fixed four-month window (1 March-1 July 2026) and will not be extended. Care recipients (older adults) will be ≥65 years with RA and frailty classified as Clinical Frailty Scale (CFS) 4-7. Caregivers will be ≥18 years, provide unpaid support, and report at least moderate burden defined as a Caregiver Burden Scale (CBS) mean score >1.99 at screening. Participants will be recruited from Rigshospitalet (Center for Rheumatology and Spine Diseases) and rheumatology departments in Køge, Slagelse, and Holbæk. Identification uses routine patient-reported outcomes (DANBIO) with invitation of potentially frail patients (e.g., MDHAQ >1.0) followed by telephone screening and CFS assessment; eligible patients nominate a caregiver who is then screened using CBS.

Intervention INSPIRE is delivered by a trained healthcare professional over ~12 weeks and comprises three contacts: an initial consultation (60-90 min), a brief follow-up (15-30 min), and a final consultation (30-60 min). Content is tailored using a toolbox addressing validation of the caregiver role, emotional/practical support, education, communication, and navigation across health and municipal services. Involvement of the older adult in consultations is optional and based on preferences of both parties.

Outcomes Feasibility outcomes include recruitment (screened/eligible/consented), retention at 12 weeks, questionnaire completeness, and deliverability (session completion, mode, duration). Acceptability will be assessed post-intervention using the Acceptability of Intervention Measure and supplemented by brief acceptability/feasibility questions and qualitative interviews. Fidelity and tailoring will be documented using structured session notes. Exploratory outcomes include caregiver burden measured by Caregiver burden scale, quality of life measured by WHOQOL-BREF (caregiver and older adult), and physical function measured by MDHAQ .

Progression criteria Pre-specified criteria include approximately 50% recruitment of those approached, ≥85% retention, and high fidelity, reviewed using a trafficlight approach (go/amend/stop).

Ethics and dissemination Written informed consent will be obtained from both the older adult and the caregiver prior to baseline data collection, with separate consent for any study components each participant takes part in (e.g., consultations, interviews). Findings will be disseminated through peer-reviewed publication, conferences, and stakeholder summaries.