The Impact of Outpatient Pooling Reform on Patients’ Out-of-Pocket Burden: Evidence from China

Abstract

Objective: This study aims to systematically evaluate the effects of the outpatient pooling reform under the Urban Employee Basic Medical Insurance (UEBMI) in Chongqing, focusing on patient utilization outcomes in a tertiary hospital setting. The primary objective is to assess the extent to which the policy reduces patients’ outpatient financial burden. In addition, through heterogeneity analysis of chronic disease patients and elderly populations, the study further examines the institutional effectiveness of the policy in providing targeted protection for high-need groups.

Methods: This study is based on comprehensive outpatient claims data from a large tertiary hospital in Chongqing, covering the period from January 2023 to December 2024. The dataset comprises approximately 600,000 insured individuals and 1.67 million outpatient visit records, forming a high-frequency micro-level panel dataset. First, an interrupted time series (ITS) model is employed to identify macro-level trends and immediate structural breaks at the time of policy implementation, with Newey–West heteroskedasticity and autocorrelation consistent standard errors applied to correct for serial correlation. Second, a two-way fixed effects (TWFE) model is constructed to track within-individual behavioral changes before and after policy implementation, controlling for individual heterogeneity and seasonal effects to identify the net micro-level impact of the policy. Finally, robustness checks are conducted through placebo tests using pseudo-policy implementation dates and by replacing the age threshold used to define elderly status.

Results: The empirical analysis yields several key findings. In terms of financial burden, the policy demonstrates a significant and robust reduction effect. The ITS results show an immediate decline of 12.5 percentage points in the self-payment ratio (95% CI: -0.169, -0.080). The TWFE model indicates that, for the same individual, the self-payment ratio decreases by an average of 24.2 percentage points, while total out-of-pocket expenditure declines by more than 58%. Heterogeneity analysis further reveals that the policy provides disproportionately greater protection for high-need populations. Specifically, the reductions in total out-of-pocket expenditure for chronic disease patients and elderly individuals exceed those of the baseline group by an additional 5.3% and 5.1%, respectively.

Conclusion: This study demonstrates that the outpatient pooling reform under UEBMI in Chongqing has led to a substantial reduction in patients’ outpatient financial burden. By incorporating pooled fund reimbursement, the policy effectively lowers out-of-pocket payments, with particularly pronounced benefits observed among elderly individuals and patients with chronic diseases.