Economic Hardship and Work Intensity Predict Job Burnout Among Chinese Medical Residents: The Chain Mediating Role of Sleep Disturbance and Professional Identity, and Implications for Standardized Residency Training

Objective This study aimed to construct and verify a moderated chain mediation model to explore the chain mediating role of sleep disturbance (assessed by the Insomnia Severity Index, ISI) and professional identity (measured by the Professional Identity Scale, PIS) between economic hardship/work intensity and job burnout (evaluated by the Maslach Burnout Inventory, MBI) among Chinese medical residents, and to examine the moderating effect of perceived organizational support (assessed by the Perceived Organizational Support Scale, POS) on the chain mediation path. Methods A cross-sectional survey was conducted among 469 medical residents using standardized scales (MBI, ISI, PIS, POS) and self-designed questionnaires on economic hardship and work intensity. SPSS 26.0 and Mplus 8.3 were used for common method bias test, correlation analysis, and moderated chain mediation model verification. Results ①The moderated chain mediation model showed good fit (χ²/df=2.136, RMSEA=0.049, CFI=0.935, TLI=0.924, SRMR=0.046). ②Sleep disturbance and professional identity played a significant chain mediating role in the relationship between economic hardship and job burnout (indirect effect=0.127, 95%CI: 0.089-0.165) and between work intensity and job burnout (indirect effect=0.183, 95%CI: 0.138-0.229), accounting for 32.6% and 39.1% of the total effect respectively. ③Perceived organizational support significantly moderated the path from sleep disturbance to professional identity in the total sample, such that the negative impact of sleep disturbance on professional identity was weaker in the high perceived organizational support group (standardized β=-0.214, p<0.001) than in the low group (standardized β=-0.386, p<0.001). Conclusion Economic hardship and work intensity affect job burnout of medical residents through the chain mediation of "sleep disturbance→professional identity", and perceived organizational support can buffer the negative link between sleep disturbance and professional identity. These findings clarify the multi-path influence mechanism of job burnout among medical residents, providing actionable implications for optimizing China's standardized residency training—including economic support enhancement, workload management, and professional identity education—to improve residents' occupational well-being.