Impact of the resident duty hours on in-training examination score: A nationwide study in Japan

The relationship between duty hours (DH) and the performance of postgraduate residents is needed to establish appropriate DH limits. This study explores their relationship using the General Medicine In-training Examination (GM-ITE).

In this cross-sectional study, GM-ITE examinees of 2019 had participated. We analyzed data from the examination and questionnaire, including DH per week (eight categories). We examined the association between DH and GM-ITE score, using random-intercept linear models with and without adjustments.

Five thousand five hundred and ninety-three participants (50.7% PGY-1, 31.6% female, 10.0% university hospitals) were included. Mean GM-ITE scores were lower among residents in Category 2 (45-50 h; mean score difference, -1.05; p < 0.001) and Category 4 (55-60 h; -0.63; p = 0.008) compared with residents in Category 5 (60-65 h; Reference). PGY-2 residents in Categories 2-4 had lower GM-ITE scores compared to those in Category 5. University residents in Category 1 and Category 5 showed a large mean difference (-3.43; p = 0.01).

DH <60-65 h per week was independently associated with lower resident performance, but more DH did not improve performance. DH of 60-65 h per week may be the optimal balance for a resident's education and well-being.