BackgroundThe training of peer supporters is critical because the success of the entire peer support intervention depends on the knowledge and experience that peer supporters can share with other patients. The objective of this study was to evaluate the pilot implementation of a specialist nurse-led self-management training programme for peer supporters with type 2 diabetes mellitus (T2DM) with or without comorbid hypertension (HTN) at the primary healthcare level in Slovenia, in terms of feasibility, acceptability, and effectiveness.MethodsA prospective pre-post interventional pilot study was conducted in two Community Health Centres (CHC) in Slovenia from May 2021 to August 2022. Purposive sampling was employed to recruit approximately 40 eligible volunteers to become trained peer supporters. A specialist nurse-led structured training lasting 15 h over a 2-month period was delivered, comprising four group and two individual sessions. The comprehensive curriculum was based on interactive verbal and visual learning experience, utilising the Diabetes Conversation Maps™. Data were collected from medical records, by clinical measurements, and using questionnaires on sociodemographic and clinical data, the Theoretical Framework of Acceptability, knowledge of T2DM and HTN, and the Appraisal of Diabetes Scale, and evaluation forms.ResultsOf the 36 participants, 31 became trained peer supporters (retention rate of 86.1%). Among them, 21 (67.7%) were women, with a mean age of 63.9 years (SD 8.9). The training was evaluated as satisfactory and highly acceptable. There was a significant improvement in knowledge of T2DM (p < 0.001) and HTN (p = 0.024) among peer supporters compared to baseline. Six months post-training, there was no significant improvement in the quality of life (p = 0.066), but there was a significant decrease in body mass index (BMI) (p = 0.020) from 30.4 (SD 6.2) at baseline to 29.8 (SD 6.2).ConclusionThe pilot implementation of a specialist nurse-led self-management training for peer supporters was found to be feasible, acceptable, and effective (in the study group). It led to improvements in knowledge, maintained disease control, and promoted positive self-management behaviours among peer supporters, as evidenced by a decrease in their BMI over six months. The study emphasises the need for effective recruitment, training, and retention strategies.Trial registrationThe research is part of the international research project SCUBY: Scale up diabetes and hypertension care for vulnerable people in Cambodia, Slovenia and Belgium, which is registered in ISRCTN registry (https://www.isrctn.com/ISRCTN41932064).