Impact of per diem payment on medical expenditure, service efficiency, and quality of care for patients with mental disorders: an interrupted time series study

The high cost of hospitalization for people with mental disorders can push them into poverty, thereby exacerbating health inequities. While per diem payment (PDP) reforms aim to address this issue, there is limited evidence on the effects of PDP reform in China. This study evaluates the effects of PDP implementation on hospitalization burden, service efficiency, and care quality for patients with mental disorders. Interrupted time series analysis (ITSA) was used to evaluate the impact of PDP reform on hospitalization burden, service efficiency, and care quality of hospitalization in primary and secondary hospitals. Policy implementation in January 2022 served as the intervention time point. All data were obtained from the City W Medical Insurance Bureau, China. After the PDP reform, the average cost per hospitalization (primary hospitals: β3 = -0.044, P < 0.001; secondary hospitals: β3 = -0.021, P < 0.021), the average out-of-pocket (OOP) per hospitalization (primary hospitals: β3 = -0.034, P < 0.001; secondary hospitals: β3 = -0.042, P < 0.001) and the average basic medical insurance (BMI) reimbursement per hospitalization (primary hospitals: β3 = -0.045, P < 0.001; secondary hospitals: β3 = -0.020, P = 0.037) of people with mental health conditions in primary and secondary hospitals all showed a downward trend. Before the PDP reform, the average length of stay (ALOS) in secondary hospitals showed an upward trend (β1 = 1.384, P = 0.002). The 30-day all-cause admission rate of patients with mental disorders in primary and secondary hospitals showed a downward trend after the reform (primary hospitals: β3 = -0.029, P = 0.009; secondary hospitals: β3 = -0.018, P = 0.008). The PDP reform effectively reduced the financial burdens and improved equitable healthcare access for patients with mental disorders. While enhancing service efficiency and resource allocation, policymakers should monitor potential unintended consequences including insurance fund underutilization and ensure sustained care quality.