Effectiveness of link workers providing social prescribing on health outcomes and costs for adult patients in primary care and community settings. A protocol for a systematic review of the literature. [version 2; peer review: 2 approved]

Introduction: The use of link workers for social prescribing and health and social care coordination is increasing, but there is insufficient data to demonstrate their effectiveness or for whom they work best. Multimorbidity is increasing in prevalence and affects those living in deprived areas ten years earlier than affluent areas. This systematic review aims to examine the evidence for the effectiveness and costs of link workers in improving health outcomes. We will also look for evidence for the use of link workers specifically for people living with multimorbidity and in deprived areas. Methods: Databases of published and grey literature will be searched for randomised and non-randomised controlled trials examining use of link workers based in primary care for community dwelling adults compared to usual care. Primary outcomes will be health related quality of life and mental health. Data on costs will be extracted. Studies will be selected for inclusion by title and abstract review by two reviewers. A Preferred Reporting Items for Systematic Reviews (PRISMA) flow diagram will document the selection process. A standardised form will be used to extract data. Data quality will be assessed using the Cochrane Risk of Bias tool for randomised controlled trials, a narrative synthesis will be completed and the GRADE assessment tool used to comment on evidence quality. A meta-analysis of effect size of primary outcomes and subgroup analysis for multimorbidity and social deprivation will be performed if there are sufficient comparable data. Conclusion: This systematic review will give an important overview of the evidence for the use of link workers providing social prescribing and health and social care coordination in primary care. This will help inform intervention development and guide policy makers on whether these interventions are cost effective and which groups stand to benefit most. Prospero registration: CRD42019134737 (04/07/2019).