The Workwell trial: protocol for the process evaluation of a randomised controlled trial of job retention vocational rehabilitation for employed people with inflammatory arthritis

Background: The Workwell trial is a multi-centre randomised controlled trial with the aims of evaluating the effectiveness and cost-effectiveness of job retention vocational rehabilitation for employed people with inflammatory arthritis, who are experiencing work difficulties due to their arthritis. Vocational rehabilitation is delivered by health service occupational therapists, who have received additional training in providing this Workwell intervention. A process evaluation will be undertaken alongside the main trial to investigate implementation fidelity; understand key stakeholders’ perspectives of the intervention and the social and structural context in which the intervention is provided; and explore issues related to future implementation in clinical practice. This protocol describes the aims, objectives, and methodology of the Workwell trial process evaluation. Methods: This mixed methods process evaluation will follow the Medical Research Council’s Guidance on process evaluations for complex interventions. It will be underpinned by the conceptual framework for implementation fidelity (CFIF) and normalisation process theory (NPT). We will analyse treatment records, work assessments, and treatment notes to ascertain implementation fidelity. Semi-structured interviews with trial participants, their employer/line managers, treating therapists, and their therapy service managers will be undertaken to explore perceptions of the intervention, contextual factors, and potential for future implementation in practice. Interview topic guides will be informed by NPT. Therapists’ views about Workwell training will be explored via questionnaires following training, and interviews and focus groups following treatment delivery to inform future implementation. Quantitative data will be analysed descriptively. Qualitative data will be analysed using thematic analysis. NPT will guide data analysis and interpretation. Findings from the different elements of this embedded design process evaluation will be reported separately and then the elements integrated. The process evaluation data will be analysed independently of the Workwell trial outcome evaluation. The process evaluation data will then be reviewed in the light of the trial findings. Discussion: Few trials of job retention vocational rehabilitation in arthritis have included process evaluations. This process evaluation will assist in understanding factors influencing trial outcomes and identifying potential contextual barriers and facilitators for the potential implementation of Workwell vocational rehabilitation into clinical services. Trial registration: ClinicalTrials.gov NCT03942783. Registered on 08 May 2019. ISRCTN Registry ISRCTN61762297. Registered on 13 May 2019. Retrospectively registered.