Background: 
South Africa (SA) is currently home to the largest population of people with diabetes mellitus in Africa. Diabetes in SA affects the population across ethnic and income diversity, with the previously disadvantaged and often considered as a low risk group for diabetes, being among the most affected. For each South African with diabetes, there are two others at high future risk of the disease. Therefore, in addition to diagnosing and appropriately treating those with the disease, efforts are needed to prevent the full development of diabetes among those South Africans at high future risk of the condition. Efficacy trials of diabetes prevention programmes (DPP) have provided evidence of the effectiveness of lifestyle interventions in preventing or postponing the onset of diabetes. Completed or ongoing implementation studies of DPP around the world are providing additional evidence to support the application of evidence from efficacy trials of DPP, using less intensive approaches and less skilled workers such as community health workers (CHW) as interventions implementers. 
Aims: 
The proposed study therefore aims: (i) to determine the characteristics that community health workers in DPPs should possess to have successful intervention outcomes, (ii) to establish best practices/existing CHW training models utilised in DPP interventions internationally; (iii) to adapt and translate the CHW training models to be culturally and contextually appropriate for use in SA; (v) to implement the adapted training model & pilot a small/short-term DPP intervention to establish effectiveness. 
Method: 
Phase 1: Desktop survey/systematic review (complete)
We developed a systematic review protocol using guidelines described by the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P). The electronic databases searches were done on MEDLINE via PubMed Central, EBSCOHost, and SCOPUS/EMBASE. These searches were limited to publications using English as language. Two authors independently identified potentially relevant studies by reviewing titles and abstracts retrieved from the aforementioned databases. The full texts of studies identified as potentially relevant were retrieved and screened in duplicate for inclusion. 
Phase 2: The development of a diabetes prevention focused, CHW training model for South Africa (in progress)
1.	Identify best practice CHW training models from the systematic review (Phase 1) 
2.	Using a community based participatory approach stakeholders, including community leaders, community members, diabetes experts, primary health care providers, dieticians, sports scientists, NPO’s employing CHWs in the areas etc. will be invited to review and give input into existing best practice models and assist researchers in adapting it to be appropriate for the communities we wish to serve. 
3.	Two best practice CHW training models will be identified to take forward into the piloting phase.
4.	The two identified models will be adapted for the various communities in the South African DPP that targets Black and Coloured urban communities in the Western Cape (as a point of entry).
Phase 3: Piloting of the two culturally tailored DPP lifestyle intervention CHW training models (next phase) 
Results: 
Phase1: 
Database searches identified 18 906 entries; after removal of screened duplicate titles and abstracts, 182 publications were selected for further full-text evaluation. Forty-one papers fulfilled the inclusion criteria and form the basis of this review. These 41 papers reported on 33 studies with companion papers comprising protocol papers, pilot studies, cost analyses and process evaluation papers. 
The profile, scope of roles played, and training received by CHW varied substantially across programmes. The duration of the training varied considerably among studies, from a single one-hour session to 40 hours and even 100 hours or more. Overall, the training would be culturally sensitive and/or appropriate. Topics covered included the importance of good nutrition, benefits of increased physical activity, communication and leadership skills required to run a group session and impart knowledge, and some theoretical background on the intervention as well as motivational interviewing as a method to facilitate behaviour change. 

Discussion:
There is evidence indicating improvements in participant knowledge and behaviour as well as physiological outcomes to various degrees. Additional research, however, is needed to understand the exact role/contributions CHW make in multicomponent interventions that lead to successful outcomes but the pathway is not clear. More research, and especially evaluations of CHW programmes, are required and to identify optimal roles, training and support for CHW working in DPP.

Towards an evidenced based community health worker training model for diabetes prevention