Impact of an experiential advance care planning training program on first-year internal medicine residents: a longitudinal mixed-methods study

Advance Care Planning (ACP) is a crucial component of person-centered care but remains underutilized in Thailand. Internal medicine physicians often encounter barriers, including low confidence, inadequate communication skills, and limited formal training. Using a mixed-methods design, this study aimed to evaluate the effectiveness of a multimodal, experiential ACP training program, focusing on the primary outcomes of internal medicine residents’ attitudes, confidence, and knowledge, and to explore the educational implications of interrelationships among these outcomes. This mixed-methods study involved the entire cohort of 50 first-year internal medicine residents who participated in a two-day experiential ACP workshop followed by two monthly “Circle of Learning” reflection sessions. For the longitudinal quantitative analysis, 34 participants who completed the full follow-up were included. Knowledge was assessed at baseline and immediately post-workshop; attitudes and confidence were assessed at baseline, immediately post-workshop, and at two and fifteen months post-intervention. Data were analyzed using McNemar’s tests, paired t-tests, repeated-measures ANOVA, and correlation analyses. Qualitative data were collected through semi-structured interviews with a subset of 10 participants. The program was grounded in experiential and transformative learning frameworks. Among the 34 residents who completed full follow-up, significant improvements were observed in ACP-related attitudes and confidence, including reduced perceived barriers, improved legal-perspective attitudes, and reduced communication hesitation. Knowledge scores increased from 7.74 to 8.65 out of 9 ( p < 0.001). Notably, changes in attitude and confidence were positively correlated ( r = 0.493, p = 0.003). Correlation analyses also revealed that overall attitude scores were strongly associated with key subdomains, including perceived barriers and legal perspective, both before and after the training. Qualitative analysis identified three main themes: (1) experiential role-play bridged the theory–practice gap, (2) personal value reflection catalyzed clinical empathy, and (3) clinical realities and the need for longitudinal support. A structured ACP training program that integrates experiential and reflective methods can effectively improve and sustain residents’ communication readiness for ACP. Attention to attitudinal transformation and its relationship with confidence is critical to designing impactful educational interventions in serious illness care. Thai Clinical Trials Registry (TCTR), TCTR20250911003; registered September 11, 2025 (retrospectively registered).