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

Abstract

Objective: This study systematically evaluates the financial burden on outpatient visits following implementation of the outpatient pooling reform among Urban Employee Basic Medical Insurance enrollees in Chongqing. The research focuses on the evaluation of the degree to which the policy reduces the burden of outpatient expenses. In addition, through the analysis of the heterogeneity of chronic diseases and the elderly group, the institutional effectiveness of the policy in accurately guaranteeing the newly-needed population is further explored.

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 the following core findings. In the cost burden dimension, the policy showed a significant and robust burden reduction effect, and the ITS showed that the proportion of out-of-pocket payment decreased by 12.5 percentage points (95% CI: -0.169, -0.080); the TWFE model showed that the proportion of out-of-pocket expenses of the same patient decreased by 24.2 percentage points on average, and the total amount of absolute out-of-pocket expenses decreased by more than 58%. Heterogeneity analysis confirmed that the policy had significant skewed protection characteristics for high-need populations, and the decrease of absolute total out-of-pocket payments for patients with chronic diseases and the elderly was 5.3% and 5.1% more than that of the baseline group, respectively.

Conclusion: This study shows that the outpatient pooling reform of medical insurance for workers in Chongqing significantly reduced patients’ cost burden. Through the intervention of the pooling fund, the policy has reduced the outpatient out-of-pocket expenses of the insured, especially the burden reduction effect of the elderly and the chronic disease group.