Interrupted time series analysis for the impact of integrated medical insurance on direct hospitalization expense of catastrophic illness

In 2016, China initiated the merge of the urban resident basic medical insurance scheme and new rural cooperative medical scheme into one unified health insurance scheme: the urban and rural resident basic medical insurance. This study investigates the impact of integrated insurance on the direct hospitalization cost of inpatients with catastrophic illnesses. An interrupted time series analysis was conducted based on a sample of 6174 inpatients with catastrophic illness from January 2014 to December 2018. The factors surveyed included per capita total inpatient expense, out-of-pocket expense, and reimbursement ratio. Univariate analysis indicated that after the implementation of the unified urban and rural medical insurance, the reimbursed expense increased from 9398 to 13,842 Yuan (P < 0.001), average reimbursement ratio increased from 0.57 to 0.59 (P < 0.05). Expenses on both western and traditional medicines increased, although the proportion of medicine expense decreased after the integration. Interrupted time series analysis showed that per capita total inpatient expense and per capita out-of-pocket expense increased but showed a gradually decreasing trend after the integration. After the integration of urban and rural medical insurance, the average reimbursement ratio increased slightly, which had limited effect on the alleviation of patients’ financial burden. Furthermore, the integration effect on inpatient expense is offset by increased out-of-pocket medical expense due to suspected supplier-induced demand.