A protocol for a systematic review of process evaluations of interventions investigating sedentary behaviour in adults

Introduction
Sedentary behaviour is defined as any waking behaviour characterised by low energy expenditure ≤1.5 Metabolic Equivalents (METs) while in a sitting, lying or reclining posture. The expanding evidence base suggests that sedentary behaviour may have a detrimental effect on health, wellbeing, and is associated with an increased risk of all-cause mortality.
We aim to review process evaluations of randomised controlled trials (RCTs) which included a measure of sedentary behaviour in adults in order to develop an understanding of intervention content, mechanisms of impact, implementation and delivery approaches and contexts, in which interventions were reported to be effective or effective. A secondary aim is to summarise participants, family, and staff experiences of such interventions.
Methods and analysis:
Ten electronic databases and reference lists from previous similar reviews will be searched. Eligible studies will be process evaluations of RCTs that measure sedentary behaviour as a primary or secondary outcome in adults. Interventions delivered in schools, colleges, universities or workplaces will be excluded as this review is part of a programme to develop a community-based intervention to reduce sedentary behaviour in stroke survivors. Two reviewers will perform study selection, data extraction, and quality assessment. Disagreements between reviewers will be resolved by a third reviewer. Process evaluation data to be extracted include: the aims and methods used in the process evaluation; implementation data; mechanisms of impact; contextual factors; participant, family, and staff experiences of the interventions. Trial data to be extracted include: trial design; participant numbers; duration and content of the intervention; outcome results (if necessary, this information will be sought outside of the process evaluation paper e.g. the trial paper)_
A narrative approach will be used to synthesise and report qualitative and quantitative data. Reporting of the review will be informed by Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidance.

Ethics and dissemination:
Ethical approval is not required as it is a protocol for a systematic review. Findings will be disseminated through peer-reviewed publications and conference presentations.
Protocol registration number: CRD42018087403