Exploring how PRIME-Parkinson care is implemented and whether, how and why it produces change, for who and under what conditions: a protocol for an embedded process evaluation within the PRIME-UK randomised controlled trial
Authors: Lloyd Katherine , Tenison Emma , Smith Safi , Lithander Fiona , Kidger Judi , Brant Heather , Redwood Sabi , Ben-Shlomo Yoav , Henderson Emily J 
Published: December 2024

ABSTRACTIntroductionThe PRIME-UK randomised controlled trial (RCT) aims to establish whether a model of care that seeks to be proactive, integrated and empower participants, caregivers and healthcare professionals can improve outcomes in people with parkinsonism. Given that this intervention is novel and complex, understanding whether and how the intervention will be acceptable, implementable, cost effective and scalable across contexts are key questions beyond that of whether ‘it works’. We describe an embedded process evaluation to answer these questions, which aims to support interpretation of the trial results, refinement of the intervention and support future scaling of the PRIME-Parkinson model of care.Methods and analysisA mixed methods approach will be used to collect data across four process evaluation domains: implementation, mechanism of change, acceptability and context. Quantitative data will be collected prospectively from all participants and analysed descriptively with exploratory tests of relationships as power allows. Qualitative data will be collected through semi-structured interviews with a purposively sampled sub-population of participants, caregivers and staff members as well as case studies where relevant. Interview transcripts will be analysed thematically using interpretive qualitative analysis. Synthesis of quantitative and qualitative data will also be performed to draw conclusions.Ethics and disseminationThe quantitative data will be collected as part of the main PRIME-UK RCT which was been granted NHS REC approval (21/LO/0387) on 27th July 2021. The qualitative data will be collected as part of a sub-study, ‘PRIME-Qual’, which was granted NHS REC approval (21/LO/0388) on 14th July 2021. The mixed methods process evaluation will be published after the conclusion of the trial in addition to the main trial findings.Trial registration numberNCT05127057Data availability statementAccess to the data will be available through application to the Chief Investigator. Pseudo-anonymised data may be shared with other researchers to enable knowledge synthesis.ARTICLE SUMMARYStrengths and limitations of this studyThis is a pre-planned process evaluation of a complex intervention, which uses robust mixed methodology to support understanding and interpretation of the main trial findingsThis process evaluation is embedded within a RCT which aims to recruit a representative sample of people living with parkinsonism, meaning the process evaluation has potential to gather a broad range of perspectivesOur mixed methods approach provides breadth of data across the study population and more in-depth exploration of themes in a purposively sampled sub-populationThe main limitation is that statistical power will limit the use of statistical tests in the analysis of quantitative data across subgroups.