Table 1.

Characteristics of included studies

Study	Setting	Randomisation	Participants	Interventions	Outcomes
Turner 2012[27]	US	RCT 2 arm: Patient level	280 Patients with uncontrolled hypertension based on average of measurements from visits over 2-year period; prescribed 2+ antihypertensive medication	Peer training: An experienced ‘lead peer coach’ demonstrated telephone support skills and techniques and 11 peers practiced calls.	SM, CO
				Frequency of calls: 3 months of calls by peers; on alternate months, 2 practice visits to review a personalised 4-year heart disease risk calculator and view slide shows; peers shared concerns over challenging cases.
				Content of calls: Assessed patient attitudes whist giving evidence-based advice; offered role modelling and perceived behavioural control advice (informational, appraisal and emotional support).
				Control: Usual care plus heart disease brochures (AHA).
Walker 2011[28]	US	RCT 2 arm: Patient level	526 Patients with type 2 diabetes with HbA1c level ≥7.5%; prescribed one or more oral medications.	Training: ‘Non clinical health educators’ were trained by a diabetes educator nurse.	SM, PROMS
				Frequency of calls: 10 calls at 4–6 week intervals over 12 months.
				Content of calls: Callers used a manual developed to improve self-efficacy and empowerment (informational, appraisal and emotional support). Peers encouraged patients to choose from topics including diabetes medication adherence and addressing and maintaining lifestyle changes through healthy eating and physical activity.
				Calls were tailored to each patient.
				Control: Received high quality self-management materials by mail.
Heisler 2010[29]	US	RCT 2 arm: Patient level	244 Patients with type 2 diabetes with HbA1c level ≥7.5% during previous 6 months	Peer training: 125 peers attended a group session to set diabetes goals, receive peer communication skills training, and receive support from an age-matched ‘peer partner’.	SM, PROMS, HU
				Frequency of calls: Peers were encouraged to talk weekly using a telephone that recorded call occurrence. Optional patient-led group sessions at 1, 3, and 6 months.
				Content of calls: Sharing education; emotional concerns and progress on self-management; and motivational interviewing (informational, appraisal and emotional support).
				Control: Enhanced usual care consisting of an educational session plus support via nurse care manager.
Dale 2009[9]	UK	*RCT 3 arm: Patient and nurse level	231 Patients with type 2 diabetes with inadequate glycaemic control (raised HbA1c level).	Peer training: 9 ‘Peer supporters’ and 12 practice nurses attended a communication skills training programme and delivered calls for 6 months.	SM, PROMS, HU
				Frequency of calls: The first call was made 3–5 days later and the following days: 7–10, 14–18, 28–35, 56–70, 120–50.
				Content of calls: Sharing education; increasing self-efficacy, empowerment, and self-management; facilitating goal-setting and active listening, including motivational interviewing (informational, appraisal and emotional support).
				Control: Usual care.
Samuel-Hodge 2009[30]	US	RCT 2 arm: Cluster by 24 churches	201 Patients with type 2 diabetes, defined as diagnosis of diabetes at ≥20 years with no history of ketoacidosis.	Training: A counselling visit by a dietician; 12 bi-weekly group education sessions led by ‘CDAs’; lay, selected based on church employees and trained over 1-month at each church.	SM, PROMS
				Frequency of calls: CDA monthly calls over 1 year.
				Content of calls: Providing education; motivational interviewing; goal-setting; self-management skills and active listening skills, including motivational interviewing (informational, emotional and appraisal support).
				Control: Mailing of 2 pamphlets.
Parry 2009[31]	Canada	RCT 2 arm.	101 Patients first time non-emergency post CABG surgery, ready for discharge.	Peer training: 14 ‘Peer volunteers’ with cardiac problems were trained to share surgery experiences; provided calls for 8 weeks post discharge.	SM, PROMS, HU
				Peers focused conversations on self-management and providing encouragement to attend a rehabilitation programme.
				Frequency of calls: Average of 12 calls, 30 minutes in duration.
				Content of calls: Sharing experiences and active listening skills including motivational interviewing (informational, emotional and appraisal support).
				Control: Received preoperative and postoperative education.
Batik 2008[32]	US	RCT 2 arm: Patient level	14 Patients with type 2 diabetes ≥ 65 years.	Training: Volunteers (number unclear); active, older adults, already engaged in senior centre programs, provided ‘lay’ motivational telephone support for 6 months. Training involved learning how to increase self-efficacy in relation to individuals’ readiness to change.	SM, HU
				Frequency of calls: The frequency and number of calls is unclear.
				Content of calls: Increasing physical activity levels rather than heart rate goals; increasing self-efficacy and self-management skills; and listening skills, including motivational interviewing (informational, appraisal and emotional support).
				Control: Delayed PALS intervention 1 year on.
Carroll 2007[33]	US	RCT 2 arm: Patient level	247 Unpartnered patients post MI and CABG surgery ≥ 65 years.	Peer training: Practice nurses trained peers according to a validated peer training program involving elders with MI. Peer advisers were matched to patient participants in relation to age and gender.	SM, HU
				Frequency of calls: 1 Community based home-visitwithin 72 hours and calls at 2, 6, and 10 weeks from a nurse and 12 weekly telephone calls from 45 ‘peer advisors’.
				Content of calls: Imparting cardiac information; motivational interviewing; implementing social support and increasing self-efficacy to improve physical and mental health (informational, appraisal and emotional support).
				Control: Usual care.
Young 2005[34]	UK	RCT 2-arm: Patient-level.	591 Patients with type 2 diabetes with diagnosis ≥ I year.	Training: ‘PACCTS’ delivered by lay ‘telecarers’ with support on treatment changes from DSN. DSNs delivered 3-month training program to telecarers on principles of: managing type 2 diabetes; self-management; communication skills; focussed listening; building and managing a telephone relationship; change management; motivational interviewing; and use of the PACCTS application.	HU, SM
				Frequency of calls: Calls performed every 3-months if HbA1c was <7%; every 7 weeks if HbA1c was in the range of 7.1-9%; and monthly if HbA1c was >9%. PACCTS application scheduled calls based on HbA1c reading.
				Content of calls: Knowledge about diabetes; smoking cessation; medication adherence; motivational interviewing; and active listening skills (informational, emotional and appraisal support).
				Control: Usual care including lifestyle advice and drug treatment following local guidelines including comprehensive annual review.
Keyserling 2002[35]	US	*RCT 3-arm. Stratified by practice: Patient and clinician level.	200 African American women with type 2 diabetes, defined as diagnosis of diabetes at ≥20 years with no history of ketoacidosis.	Peer training: 4 Weekly, 4 hourly training sessions by community advisor; sessions were designed to promote readiness to change behaviours and social support.	SM, PROMS
				Frequency of calls: Group A: Clinic and community – 4 monthly visits with nutritionist to enhance physical activity and diet tailored to baseline attitudes. 3 group sessions and 12 monthly phone calls from ‘peer counsellor’ designed to provide social support and reinforce behaviour change; Group B: Clinic only - 3 monthly visits with nutritionist to enhance physical activity and diet tailored to baseline attitudes.
				Content of calls: Promoting and maintaining healthy eating and physical activity; medication adherence; implementing self-management based on behaviour change theory and motivational interviewing (informational, emotional and appraisal support).
				Control: Group C: ‘Minimal intervention’ education pamphlets mailed to participants.

Note: Outcomes of included studies: SM = Self-management; CO = Clinical outcomes; PROMS = Patient-reported outcome measures; HU = Health utilisation; *One arm ineligible for inclusion in our anlaysis.