Participants at the intervention Puskesmas received a structured self-efficacy program consisting of four weekly group sessions (60-90 minutes each) delivered by a trained nurse researcher. Sessions covered diabetes knowledge enhancement, personal goal setting, self-monitoring techniques, peer experience sharing, problem-solving strategies, progress review, and relapse prevention planning. The program was grounded in Bandura's Self-Efficacy Theory, targeting mastery experience, vicarious experience, verbal persuasion, and physiological/emotional states.

Participants at the control Puskesmas received usual care as routinely provided by the primary health center (Puskesmas). No additional intervention was given during the study period. Participants in this group were offered the self-efficacy program after data collection was completed.

A structured group-based behavioral intervention grounded in Bandura's Self-Efficacy Theory. The program consisted of four weekly sessions (60-90 minutes each) facilitated by a trained nurse researcher. Session 1 focused on diabetes knowledge enhancement and personal goal setting. Session 2 covered self-monitoring techniques and identifying barriers to self-care. Session 3 involved peer experience sharing and problem-solving strategies. Session 4 included review of progress, reinforcement of skills, and relapse prevention planning. The intervention targeted four sources of self-efficacy: mastery experience, vicarious experience, verbal persuasion, and physiological/emotional states.

Measured using the Summary of Diabetes Self-Care Activities (SDSCA) questionnaire, which assesses self-care behaviors across five domains: general diet, specific diet, exercise, blood glucose testing, and foot care. Scores represent the number of days per week (0-7) participants performed each self-care activity.

Measured using the Diabetes Self-Efficacy Scale (DSES), which assesses participants' confidence in performing diabetes self-management tasks. The scale uses a Likert-type response format with higher scores indicating greater self-efficacy.

Qualitative data collected through semi-structured interviews with a purposive subsample of intervention group participants. Interviews explored participants' perceptions, experiences, and perceived impact of the self-efficacy program on their diabetes self-management. Data were analyzed using thematic analysis.