Differential provider responses to insurance-specific point values under China’s diagnosis-intervention packet payment reform: an interrupted time-series analysis

Abstract Background China’s Diagnosis-Intervention Packet (DIP) payment reform assigns relative weights and insurance-specific point values within separate Urban Employee Basic Medical Insurance (UEBMI) and Urban-Rural Resident Basic Medical Insurance (URRBMI) pools. Persistent payment asymmetry may therefore be associated with differential provider responses. Methods We analyzed 1,746,605 inpatient admissions from all 209 healthcare institutions in City A between June 2021 and November 2023. We conducted a single-arm observational interrupted time-series analysis with budget-reconciliation breakpoints in May 2022 and May 2023. Four outcomes were analyzed: decomposed admissions, 7-day readmission, high-RW share, and low-RW share. Outcomes were aggregated to the hospital-month-insurance level and modeled with quasi-Poisson log-link models with an offset equal to log monthly admissions and hospital-clustered robust standard errors. High- and low-RW indicators used fixed pooled pre-period thresholds (P75 = 975.76; P25 = 321.00). Pooled models with insurance-by-policy interactions directly tested differential responses; analyses were stratified by primary, secondary, and tertiary hospital level. Results After the first reconciliation, the URRBMI-to-UEBMI rate ratio for decomposed admissions was 0.17 (95% CI 0.09–0.32; FDR-adjusted q < 0.001), and the corresponding ratio for 7-day readmission was 0.55 (95% CI 0.43–0.71; q < 0.001).The payment gap remained approximately 40% across phases. Residual-autocorrelation diagnostics were unremarkable (Durbin–Watson and Ljung–Box tests non-significant), per-scheme pre-reconciliation slopes did not differ from zero for decomposed admissions or 7-day readmission, although a modest differential (URRBMI relative to UEBMI) pre-trend was detected for 7-day readmission. Excluding October–December 2022 produced changes of less than 10% for most key estimates. The differential responses were concentrated in secondary and tertiary hospitals. Conclusions The DIP reform implements separate budgets and point values for the UEBMI and URRBMI pools, so that inpatients in the same DIP group receive different payments depending on their insurance type. After the reform, decomposed admissions and short-interval readmissions declined for both schemes, and markedly more for URRBMI inpatients, particularly in secondary and tertiary hospitals. This differential response has sparked concerns about hospitals potentially favoring higher-paying UEBMI inpatients. Encouragingly, the gaps between the two schemes narrowed over successive budget reconciliations as outcome-linked penalties and audit monitoring took effect, indicating positive effects in curbing payment-driven gaming and safeguarding equitable care.