CBL with integrated SDH versus CBL alone in esophageal surgery internship: a randomized controlled trial on clinical competence development

BACKGROUND: Esophageal cancer exhibits significant geographical and economic disparities, with social determinants of health (SDH) playing crucial roles in its occurrence and prognosis. While case-based learning (CBL) is mainstream in clinical internships, traditional CBL predominantly focuses on disease biology, often neglecting sociocultural contexts. At the study institution, medical students receive limited formal SDH education within the preclinical curriculum, and clinical rotations lack systematic SDH training components. Integrating SDH into medical curricula has become an international education reform priority; however, empirical research systematically incorporating SDH into clinical internship settings within China remains limited. This study explored the effectiveness of integrating SDH into CBL on clinical competence development among surgical interns. METHODS: A randomized controlled trial with individual-level randomization was employed. A total of 124 medical students completing their surgical internship at a single hospital from March 2024 to January 2026 were randomly assigned to a control group (CBL only, n = 60) or an experimental group (CBL + SDH, n = 64). Teaching was conducted using a standardized "esophageal cancer patient" case. Bias was controlled through blinding of students and outcome assessors, combined with randomization of teaching procedures, confidentiality agreements, and standardized teaching packages. Teaching effectiveness was assessed using objective structured clinical examinations (OSCE), theoretical knowledge tests, case analysis reports, and questionnaires. RESULTS: The experimental group scored significantly higher than the control group on objective assessments of history taking, medical record writing, identification and analysis of social factors, and comprehensive treatment planning and humanistic care (P < 0.001), with very large effect sizes. No significant differences were found in theoretical knowledge, physical examination, or diagnosis and medical analysis (P > 0.05). In self-assessments, the experimental group scored significantly higher on six core competency dimensions (P < 0.01), with moderate to large effect sizes. Satisfaction evaluations showed the experimental group rated content and context, thinking training, and competence relevance significantly higher (P < 0.01). CONCLUSIONS: Integrating SDH into CBL significantly enhances surgical interns' competence to address social health issues without compromising core medical knowledge, offering an effective strategy for biopsychosocial medical education.The observed benefits should be interpreted as the overall effect of the enhanced educational package (SDH-integrated CBL with SP encounters, reflective writing, feedback, and mini-OSCE practice), rather than as the effect of SDH content alone.