Table 2.

Details of peer support and providers.

INTERVENTION STUDIES (n = 22)
AUTHOR, YEAR	COUNTRY	DEFINITION OF PEER SUPPORT	SETTING	PROVIDERS
Ahmadi, 2018 [34]	Iran	Peer education is an information exchange of attitudes and behaviours from individuals who are not specialists but have similar experiences.	Diabetes Clinic at a university medical center hospital.	A peer was a known diabetic with good control of blood glucose, few complications, able to manage sessions, had personal interest to collaborate and provide support, had good social communication skills (e.g., good appearance, tone of voice, eye contact) and education higher than middle school. Peers underwent 2 weeks training from the first author.
Assah, 2015 [42]	Cameroon	Peer-support care models provide a low-cost, flexible means to supplement formal healthcare support for chronic diseases.	Out of the hospital setting	A peer supporter was recruited for each of the 10 groups of the intervention arm based on their past history and clinical profile: better glycaemic and metabolic control than their peers, more compliant with their clinic visits, and more experiential knowledge on diabetes. They underwent a two-day training workshop.
Baumann, 2015 [39]	Uganda	Peer support is a promising approach toward achieving self-care goals.	Diabetes clinic	Peer champions were patients able to read and speak English who received additional training in communication skills to provide peer partners emotional support and assistance with daily management.
Castillo-Hernandez, 2021 [30]	Mexico	Provision of support from an individual member of the community, with experiential knowledge based on sharing similar life experiences.	Community centre	All peer leaders (supporters) were known diabetics with most recent HbA1C <8%. They were required to have good communication skills and were trained on basic aspects of diabetes, communication and leadership skills according to the Peer Leader Manual.
Chan, 2014# [53]	Hong Kong	Provision of support for daily management, linkage to clinical care, and ongoing social and emotional support.	3 Diabetes centres	Peer supporters were motivated patients with well-controlled T2DM who received 32 hours of training to become peer supporters. They were reinforced on the principles of communication and empathic listening and encouraged to share their positive experiences to assist their peers to manage diabetes on a day-to-day basis. Additionally, they were reminded of factors that could influence blood glucose level, eg, diet, exercise, poor sleep, stress, changes in daily routines, bodyweight, medications, and concurrent illnesses, and thus the importance of self-monitoring of blood glucose. Some of them were active members of patient groups organized by lay associations or diabetes centres.
Debussche, 2018 [8]	Mali	N/R	Community setting	Peer educators (PEs) were recruited from the local association of diabetic patients. The following criteria were used for selection – having diabetes, living in the locality, undergoing regular checks with a referent physician, volunteering to deliver educational sessions, and being fluent in both French and the local Bambara language. The recruited PEs attended an initial 4-day training program. They underwent two further evaluations before being actively involved in the project.
Gagliardino, 2013 [55]	Argentina	A reasonable approach involving people with diabetes in the delivery of education and support needed for long-term self-management.	Houssay Center in La Plata	Peers were recruited on the basis of their excellent diabetes control, self-motivation, communication and support skills and interest. They were trained for 3 days using the curriculum of the health professionals Training Course on Diabetes Education.
Ghasemi, 2019 [33]	Iran	Peer education is a process in which motivated and trained individuals are responsible for education of their peers that aims to raise awareness and improve skills in the individuals and enable them to accept their responsibility in protecting their health	Two health centres	Recruitment and details of peers was not described. The authors describe the peers to be interested and highly motivated. Peers who were training their group were further supervised by the researcher.
Ju, 2018 [43]	China	The provision of support (through activities) from an individual with experiential knowledge based on sharing of similar life experiences	Eight community health centres	Peer leaders were chosen based on residence, demographics and other characteristics, including interpersonal skills evident in interviews, time available and willingness to cooperate as part of a team and follow study protocols. Peer leaders guided participants to carry out activities with the help of community health centres or medical volunteers.
Khan, 2018 [54]	Bangladesh	People with diabetes educating other patients regarding diabetes	Outpatient Department (OPD) of BIRDEM (the Tertiary Hospital of Diabetic Association of Bangladesh)	Peer educators were diabetics for at least 5 years with the following characteristics – age>40yrs, HbA1C <7%, graduates, committed to training and willing to spend sufficient time, enthusiastic to be peer educators and residing in Dhaka city. They underwent a three-day training program with pre and post-training assessments.
Khetan, 2019 [41]	India	N/R	Community	Community health workers (CHWs) were recruited for the study and were not previously a part of the health system. The inclusion criteria do become a CHW included being a female resident of the study area for at least the past two years, between 18 and 45 years of age, having a tenth-grade level of education and possessing spoken and written knowledge of the local language. They received staggered training focused on hypertension, followed by diabetes, and then smoking. Training for each risk factor was delivered over 1 to 2 weeks (3 h/day). All CHWs were retained from the start to the end of the intervention, with zero attrition.
Latina, 2020 [40]	Grenada	Peer support is a low-cost intervention and therefore decrease CV risk.	5 Local parishes	A Peer leader was a motivated community lay-person. They underwent an additional three-hour training session on leadership and communication skills in addition to the relevant healthy behaviour promotion.
Paz-Pacheco, 2017 [36]	Philippines	‘Community catalysts,’ to promote a healthy lifestyle among people with diabetes in the community	Village health centres	Volunteer peer educators were recruited among the participants (known diabetics). They attended a two-day workshop during which they received a course manual that described both the course content and process on how to teach them.
Peimani, 2018 [35]	Iran	Peer support programs are a promising way to boost social and emotional support, help patients in day-to-day management of living with diabetes and promote linkages to clinical care	University specialty clinic.	Peers who were known diabetics were nominated by physicians and diabetes educator nurses in the clinic based on their diabetes control (HbA1C <8%), good interpersonal skills, self motivation and good active and non-judgemental listening skills. The peers were also to be able to read and write and had to attend a three-day course.
Rotheram-Borus, 2012 [45]	South Africa	N/R	Xhosa township	Peer mentors were positive role models who had lost weight and increased exercise after their T2DM diagnosis. They were trained in the management of diabetes, support processes and group management by the project team.
Sazlina, 2015 [50]	Malaysia	Assistance in applying disease management and prevention plans in daily life, emotional and social support, linkage to clinical care and on-going support.	Primary healthcare clinic.	Peer mentors were volunteers with ≥5 years of T2DM, engaged in regular physical activity, had HbA1c <8% and living in the community of the study location. Peer mentors also attended a 2-day training session.
Shahsavari, 2021 [46]	Iran	Peer support is delivered by similar people with diabetes in social and emotional contexts to improve patients’ relationships with clinical caregivers and help them manage their daily activities of a life with diabetes.	Public spaces (mosques, coffee shops or restaurants)	Peers were those diagnosed with T2DM for at least 1 year (latest HbA1c <8%), having at least a high school diploma, had basic knowledge about diabetes, had no diabetes related chronic complications, attending all peer education sessions and being approved for their communication and interpersonal skills in the face-to-face interview session by the research team.
Sreedevi, 2017 [37]	India	Peer support was defined as support from an individual with experiential knowledge based on a sharing of similar life experiences or prevention plans in daily life	Rural health training centre.	Peer mentors (PMs) were identified from the community. Eligibility criteria included having T2DM for at least 1 years with a random plasma glucose (RPG) <=250mg/dl in the last reading, someone who was generally adherent to treatment and behaviour change regimen as judged by the investigation team. Had capacity and commitment to undergo the training required, an understanding of patient confidentiality and undertaking to liaise with the concerned doctor if unanticipated problems arose during the course of the study. Peer mentors underwent a two-day training program.
Thuita, 2020 [31]	Kenya	Peer to peer social and emotional support has been shown to help people apply disease management or prevention plans in daily life, and links individuals with clinical, community, and other resources.	Thika Level 5 Hospital.	The Nutrition education with Peer-to-Peer support (NEP) group were given peer-to-peer support training in addition to the nutrition training program. Members of the peer support group were encouraged to set and share with one another other weekly goals for specific changes in their eating and physical activity behaviour. A trained peer educator living with diabetes for 13 years joined the PI during monthly meetings and encouraged participants in the peer support groups by sharing his experience.
Yin, 2015# [44]	Hong Kong	Peer support refers to the transfer of experiential knowledge of a specific behavior or coping strategy for a stressor between people who share a particular characteristic.	Managed in the usual care setting of their hospital or community-based clinic.	Peers were those living with T2DM, aged 18 to 75 years with HbA1C <8%, had a good understanding of living with diabetes, clear communication skills. They underwent the ‘train-the-trainer’ program.
Zeng, 2016 [49]	China	N/R	Community health centres	Peers were community volunteers who had received guidance from counselors. Meetings by the peers focused on (a) the management of chronic diseases, (b) healthy lifestyles, (c) psychological coping skills for dealing with diabetes and hypertension, (d) knowledge about depression and anxiety, and (e) self-awareness of negative emotions. The meetings also provided emotional and social support to the participants.
Zhong, 2015 [38]	China	Assistance in daily management, social and emotional support, linkage to clinical care and community resources, and ongoing availability of support.	Community Health Service Centers and participants homes.	Peer leaders were those diagnosed with T2DM for more than 1 year, willing to volunteer and generally adhered to both medication and behavioral management regimens. Additional criteria were altruism, positive and sociable personality, availability of time, an understanding of the importance of patient confidentiality, good relationships with community residents and leadership in their communities. They underwent 3 days’ training. Training emphasized the key functions of peer support promoted by Peers for Progress. Peer leaders were retired adults who had diabetes for a mean of 9.3 years.
OBSERVATIONAL STUDIES (n = 5)
AUTHOR, YEAR	COUNTRY	DEFINITION OF PEER SUPPORT	SETTING	PROVIDERS
Hernandez, 2021$ [52]	Cambodia	N/R	N/R	Peer Educators (PEs) were patients with diabetes and/or hypertension selected for their motivation who screened and initiated management of community members in their local villages, Training of PEs was undertaken by MoPoTsyo (Cambodian NGO).
Liu, 2020 [51]	China	N/R	Community Health Centers	Majority of the peer leaders (PLs) were individuals living with diabetes who were recruited based on existing relationships with people in the community and trained with knowledge and skills to help patients make the transition from discussing problems to taking action using a ‘Diabetes Action Plan’ as a framework.
Mwakalinga, 2021 [29]	Malawi	N/R	Kamuzu Central Hospital	Study did not specify characteristics of the peers. They were trained using support material developed by the Peers for Progress organization.
Rao, 2020$ [47]	Cambodia	Peer educator programs have been used to improve chronic disease management by providing educational support and linkages to care, particularly in resource-poor settings.	Peer educator homes	Peer educators (PEs) were community members with diabetes selected based on literacy, motivation and social aptitude. They underwent six-week training course developed by physicians, pharmacists, and experienced peer educators.
Taniguchi, 2017$ [48]	Cambodia	Peer support programs utilize peer educators who are non-professionals to provide a variety of functions, including social and emotional support, assistance with disease management, and linkage to clinical care and community resources aiming to engage patients in self-management of their disease to sustain behaviours needed to manage diabetes and decrease the risk of diabetes complications.	Typically, peer educator homes	Peer educators (PEs) were people with diabetes and were selected on their ability to read and write and their willingness to commit to fulfill the role. They received 6 weeks training.

N/A: not applicable; N/R: not reported;

# Related publications (n = 2).

$ Related publications (n = 3).