Objective  To evaluate the effect of flipped classrooms combined with case-based collaborative learning (CBCL) in teaching internal medicine in the experimental eight-year medical doctor programnew academic "4+4" pilot class(NAPC).

  Methods  Medical students from the class 2019 and class 2020 of NAPC in Peking Union Medical College were selected as the objects. A teaching method of flipped classroom combined with CBCL was applied in the course of internal medicine (inflammatory bowel disease). Through the knowledge test before and after class discussion, the students' mastery of relevant knowledge was evaluated, and the Likert scale was used to give quantitative feedback on the teaching effect.

  Results  A total of 45 medical students from NAPC were enrolled, including 20 students from class 2019 and 25 students from class 2020.A total of 42 students completed the knowledge test before class and 45 students completed the knowledge test after class.After the flipped classroom combined with CBCL, the students' correct answer rate had significantly increased on questions about the age of inflammatory bowel disease onset, severity of ulcerative colitis endoscopy, lesion range, differential diagnosis, treatment principles, clinical manifestations of Crohn's disease, and treatment principles(all P < 0.001); the median correct answer rate of all questions significantly increased 33.3(26.2, 85.7)% vs. 93.3(71.1, 95.6)%, P=0.001. Thirty students(66.7%, 30/45)completed the post-class feedback; the overall satisfaction score of the teaching mode of flipped classroom was (4.00±0.74) points.

  Conclusions  The teaching mode of flipped classroom combined with CBCL can significantly improve learning outcome in medical students of the experimental eight-year program. Students are generally satisfied with the teaching mode.