An evaluation experiment on the causal effects of differentiated medical insurance reimbursement on medical choice and medical expenses.

Introduction: Uneven distribution of health-care resources and rising medical spending have kept medical-insurance reform high on China's policy agenda. This study examines whether differentiated reimbursement can redirect patients toward lower-level providers and moderate the cost of care. Methods: We used provincial health-insurance claims, institutional operating records, and a patient-behavior survey covering December 2022 to August 2024. A difference-indifferences model was used to estimate policy effects, followed by mechanism and heterogeneity analyses. Results: Higher reimbursement rates for primary and secondary institutions increased the probability of choosing these providers. The association operated mainly through a lower out-of-pocket share and improved primary-care service capacity. Responses were stronger among patients with chronic conditions, older patients, and lower-income groups, whereas acute and severe cases continued to rely largely on tertiary hospitals. The policy also reduced average per-visit costs and individual payment burdens, although provider responses at some tertiary hospitals may attenuate the cost-control effect. Discussion: Differentiated reimbursement appears useful for supporting hierarchical care, but it is unlikely to establish a mature hierarchical medical system by itself. It should be combined with primary-care capacity building, clearer referral pathways, and payment-system reform.