Van der Wulp 2012.

Methods	Study design: RCT Unit of randomisation: patient Unit of analysis: patient Funding sources: Dutch Diabetes Research Foundation Conflicting interests: none declared
Participants	Country: Netherlands Setting: Primary care Conditions/numbers: 119 diabetes patients (type 2) (59 intervention, 60 control) Multi‐morbidity: n/a Health literacy: n/a
Interventions	Theoretical framework: Bandura's Social Cognitive Theory Focus: peer coach Type of intervention: Training for peer coaches Clinicians involved: Peer coaches (additional) Tools: A peer‐led self‐management programme was developed with input from patients, GPs and dieticians. The primary objective was to increase self efficacy in patients with Type 2 diabetes. Secondary objectives were to improve physical activity and dietary habits. Five expert patients with diabetes were recruited through advertisements. They received 3 training sessions, each lasting 3½ hours. They learnt the basic principles of motivational interviewing (how to support self efficacy, coping with resistance, showing empathy, exploring discrepancies). A script was developed for use by expert patients (peer coaches) who carried out 3 monthly 1‐hour home visits to discuss participant's priorities, goals and action plans, with subsequent follow‐up calls. During the first visit, areas for lifestyle change were explored. In the second visit, participants discussed the feasibility of lifestyle changes and set goals to work on over the next month. Progress towards the goals was evaluated in the third visit. Home visits lasted 1 hour on average. Within 2 weeks after each visit the expert patients contacted their participants by phone to evaluate the previous visit and answer any questions. Between visits participants could contact their expert patient by phone or email as often as they liked. Stages completed: Limited ‐ B, C, F Usual provider aware of patient's goals and action plans: not stated Standardisation of clinician input: Strong ‐ 5 expert patients received 3 x 3½‐hour training sessions in motivational interviewing + follow‐up meetings and supervision (p. 391). Fidelity: not reported Attrition: 13 participants dropped out (11%) and 23 did not return questionnaires (19%) Comparison: Usual care
Outcomes	Health status:psychological: Center for Epidemiologic Studies Depression Scale (CES‐D); subjective: WHO Well‐Being Index; Problem Areas in Diabetes (PAID‐2) Self‐management capabilities: Diabetes Self‐Efficacy*, Diabetes Coping; Health behaviours: Physical Activity Scale for the Elderly, Fatlist Achievement of personal goals: n/a Service use: n/a Adverse events: none reported Length of follow‐up: baseline, 3 months, 6 months
Notes	* Primary outcome measure. Power calculation ‐ 80 participants required to demonstrate difference between groups in relation to self efficacy
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A computerised randomisation model allocated participants to intervention or control (p. 396)
Allocation concealment (selection bias)	Low risk	Randomisation conducted by person not familiar with study or researchers.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not possible to blind participants or peer coaches.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Nothing reported re blinding of assessors.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing data patterns were analysed and revealed that data were missing completely at random, so missing values were imputed by means of regression analysis. Attrition accounted for in detail (p. 392)
Selective reporting (reporting bias)	Unclear risk	No published protocol. All outcome measures reported.
Other bias	Low risk	Intervention took place in participants' homes with peer coaches. Contamination unlikely.